Debugfs isn't always available in production builds that try to squeeze
every single byte out of the kernel image, but we still need a way to
toggle the timestamp and cycle counter registers so that jobs can be
profiled for fdinfo's drm engine and cycle calculations.
Drop the debugfs knob and replace it with a sysfs file that accomplishes
the same functionality, and document its ABI in a separate file.
Signed-off-by: Adrián Larumbe <[email protected]>
---
.../testing/sysfs-driver-panfrost-profiling | 10 +++
Documentation/gpu/panfrost.rst | 9 +++
drivers/gpu/drm/panfrost/Makefile | 5 +-
drivers/gpu/drm/panfrost/panfrost_debugfs.c | 21 ------
drivers/gpu/drm/panfrost/panfrost_debugfs.h | 14 ----
drivers/gpu/drm/panfrost/panfrost_device.h | 5 +-
drivers/gpu/drm/panfrost/panfrost_drv.c | 14 ++--
drivers/gpu/drm/panfrost/panfrost_job.c | 2 +-
drivers/gpu/drm/panfrost/panfrost_sysfs.c | 74 +++++++++++++++++++
drivers/gpu/drm/panfrost/panfrost_sysfs.h | 15 ++++
10 files changed, 124 insertions(+), 45 deletions(-)
create mode 100644 Documentation/ABI/testing/sysfs-driver-panfrost-profiling
delete mode 100644 drivers/gpu/drm/panfrost/panfrost_debugfs.c
delete mode 100644 drivers/gpu/drm/panfrost/panfrost_debugfs.h
create mode 100644 drivers/gpu/drm/panfrost/panfrost_sysfs.c
create mode 100644 drivers/gpu/drm/panfrost/panfrost_sysfs.h
diff --git a/Documentation/ABI/testing/sysfs-driver-panfrost-profiling b/Documentation/ABI/testing/sysfs-driver-panfrost-profiling
new file mode 100644
index 000000000000..ce54069714f3
--- /dev/null
+++ b/Documentation/ABI/testing/sysfs-driver-panfrost-profiling
@@ -0,0 +1,10 @@
+What: /sys/bus/.../drivers/panfrost/.../drm/../profiling/status
+Date: February 2024
+KernelVersion: 6.8.0
+Contact: Adrian Larumbe <[email protected]>
+Description:
+ Get/set drm fdinfo's engine and cycles profiling status.
+ Valid values are:
+ 0: Disable fdinfo job profiling sources. This disables both the GPU's
+ timestamp and cycle counter registers.
+ 1: Enable the above.
diff --git a/Documentation/gpu/panfrost.rst b/Documentation/gpu/panfrost.rst
index b80e41f4b2c5..be4ac282ef63 100644
--- a/Documentation/gpu/panfrost.rst
+++ b/Documentation/gpu/panfrost.rst
@@ -38,3 +38,12 @@ the currently possible format options:
Possible `drm-engine-` key names are: `fragment`, and `vertex-tiler`.
`drm-curfreq-` values convey the current operating frequency for that engine.
+
+Users must bear in mind that engine and cycle sampling are disabled by default,
+because of power saving concerns. `fdinfo` users and benchmark applications which
+query the fdinfo file must make sure to toggle the job profiling status of the
+driver by writing into the appropriate sysfs node::
+
+ echo <N> > /sys/bus/platform/drivers/panfrost/[a-f0-9]*.gpu/drm/card1/profiling
+
+Where `N` is either `0` or `1`, depending on the desired enablement status.
diff --git a/drivers/gpu/drm/panfrost/Makefile b/drivers/gpu/drm/panfrost/Makefile
index 2c01c1e7523e..6e718595d8a6 100644
--- a/drivers/gpu/drm/panfrost/Makefile
+++ b/drivers/gpu/drm/panfrost/Makefile
@@ -10,8 +10,7 @@ panfrost-y := \
panfrost_job.o \
panfrost_mmu.o \
panfrost_perfcnt.o \
- panfrost_dump.o
-
-panfrost-$(CONFIG_DEBUG_FS) += panfrost_debugfs.o
+ panfrost_dump.o \
+ panfrost_sysfs.o
obj-$(CONFIG_DRM_PANFROST) += panfrost.o
diff --git a/drivers/gpu/drm/panfrost/panfrost_debugfs.c b/drivers/gpu/drm/panfrost/panfrost_debugfs.c
deleted file mode 100644
index 72d4286a6bf7..000000000000
--- a/drivers/gpu/drm/panfrost/panfrost_debugfs.c
+++ /dev/null
@@ -1,21 +0,0 @@
-// SPDX-License-Identifier: GPL-2.0
-/* Copyright 2023 Collabora ltd. */
-/* Copyright 2023 Amazon.com, Inc. or its affiliates. */
-
-#include <linux/debugfs.h>
-#include <linux/platform_device.h>
-#include <drm/drm_debugfs.h>
-#include <drm/drm_file.h>
-#include <drm/panfrost_drm.h>
-
-#include "panfrost_device.h"
-#include "panfrost_gpu.h"
-#include "panfrost_debugfs.h"
-
-void panfrost_debugfs_init(struct drm_minor *minor)
-{
- struct drm_device *dev = minor->dev;
- struct panfrost_device *pfdev = platform_get_drvdata(to_platform_device(dev->dev));
-
- debugfs_create_atomic_t("profile", 0600, minor->debugfs_root, &pfdev->profile_mode);
-}
diff --git a/drivers/gpu/drm/panfrost/panfrost_debugfs.h b/drivers/gpu/drm/panfrost/panfrost_debugfs.h
deleted file mode 100644
index c5af5f35877f..000000000000
--- a/drivers/gpu/drm/panfrost/panfrost_debugfs.h
+++ /dev/null
@@ -1,14 +0,0 @@
-/* SPDX-License-Identifier: GPL-2.0 */
-/*
- * Copyright 2023 Collabora ltd.
- * Copyright 2023 Amazon.com, Inc. or its affiliates.
- */
-
-#ifndef PANFROST_DEBUGFS_H
-#define PANFROST_DEBUGFS_H
-
-#ifdef CONFIG_DEBUG_FS
-void panfrost_debugfs_init(struct drm_minor *minor);
-#endif
-
-#endif /* PANFROST_DEBUGFS_H */
diff --git a/drivers/gpu/drm/panfrost/panfrost_device.h b/drivers/gpu/drm/panfrost/panfrost_device.h
index 62f7e3527385..56c8e5551335 100644
--- a/drivers/gpu/drm/panfrost/panfrost_device.h
+++ b/drivers/gpu/drm/panfrost/panfrost_device.h
@@ -130,7 +130,10 @@ struct panfrost_device {
struct list_head scheduled_jobs;
struct panfrost_perfcnt *perfcnt;
- atomic_t profile_mode;
+ struct kobj_profiling {
+ struct kobject base;
+ atomic_t profile_mode;
+ } profiling;
struct mutex sched_lock;
diff --git a/drivers/gpu/drm/panfrost/panfrost_drv.c b/drivers/gpu/drm/panfrost/panfrost_drv.c
index a926d71e8131..6db1ea453514 100644
--- a/drivers/gpu/drm/panfrost/panfrost_drv.c
+++ b/drivers/gpu/drm/panfrost/panfrost_drv.c
@@ -20,7 +20,7 @@
#include "panfrost_job.h"
#include "panfrost_gpu.h"
#include "panfrost_perfcnt.h"
-#include "panfrost_debugfs.h"
+#include "panfrost_sysfs.h"
static bool unstable_ioctls;
module_param_unsafe(unstable_ioctls, bool, 0600);
@@ -600,10 +600,6 @@ static const struct drm_driver panfrost_drm_driver = {
.gem_create_object = panfrost_gem_create_object,
.gem_prime_import_sg_table = panfrost_gem_prime_import_sg_table,
-
-#ifdef CONFIG_DEBUG_FS
- .debugfs_init = panfrost_debugfs_init,
-#endif
};
static int panfrost_probe(struct platform_device *pdev)
@@ -663,8 +659,14 @@ static int panfrost_probe(struct platform_device *pdev)
if (err)
goto err_out2;
+ err = panfrost_sysfs_init(pfdev);
+ if (err)
+ goto err_out3;
+
return 0;
+err_out3:
+ panfrost_gem_shrinker_cleanup(ddev);
err_out2:
drm_dev_unregister(ddev);
err_out1:
@@ -681,6 +683,8 @@ static void panfrost_remove(struct platform_device *pdev)
struct panfrost_device *pfdev = platform_get_drvdata(pdev);
struct drm_device *ddev = pfdev->ddev;
+ panfrost_sysfs_cleanup(pfdev);
+
drm_dev_unregister(ddev);
panfrost_gem_shrinker_cleanup(ddev);
diff --git a/drivers/gpu/drm/panfrost/panfrost_job.c b/drivers/gpu/drm/panfrost/panfrost_job.c
index 0c2dbf6ef2a5..49413dfda2ea 100644
--- a/drivers/gpu/drm/panfrost/panfrost_job.c
+++ b/drivers/gpu/drm/panfrost/panfrost_job.c
@@ -243,7 +243,7 @@ static void panfrost_job_hw_submit(struct panfrost_job *job, int js)
subslot = panfrost_enqueue_job(pfdev, js, job);
/* Don't queue the job if a reset is in progress */
if (!atomic_read(&pfdev->reset.pending)) {
- if (atomic_read(&pfdev->profile_mode)) {
+ if (atomic_read(&pfdev->profiling.profile_mode)) {
panfrost_cycle_counter_get(pfdev);
job->is_profiled = true;
job->start_time = ktime_get();
diff --git a/drivers/gpu/drm/panfrost/panfrost_sysfs.c b/drivers/gpu/drm/panfrost/panfrost_sysfs.c
new file mode 100644
index 000000000000..072d3bf349d2
--- /dev/null
+++ b/drivers/gpu/drm/panfrost/panfrost_sysfs.c
@@ -0,0 +1,74 @@
+// SPDX-License-Identifier: GPL-2.0
+/* Copyright 2023 Collabora ltd. */
+/* Copyright 2023 Amazon.com, Inc. or its affiliates. */
+
+#include <linux/platform_device.h>
+#include <drm/drm_file.h>
+#include <drm/panfrost_drm.h>
+
+#include "panfrost_device.h"
+#include "panfrost_gpu.h"
+#include "panfrost_sysfs.h"
+
+static ssize_t
+profiling_show(struct kobject *kobj, struct kobj_attribute *attr, char *buf)
+{
+ atomic_t *profile_mode =
+ &container_of(kobj, struct {
+ struct kobject base;
+ atomic_t profile_mode; },
+ base)->profile_mode;
+
+ return sysfs_emit(buf, "%d\n", atomic_read(profile_mode));
+}
+
+static ssize_t
+profiling_store(struct kobject *kobj, struct kobj_attribute *attr,
+ const char *buf, size_t count)
+{
+ atomic_t *profile_mode =
+ &container_of(kobj, struct {
+ struct kobject base;
+ atomic_t profile_mode; },
+ base)->profile_mode;
+ int err, value;
+
+ err = kstrtoint(buf, 0, &value);
+ if (err)
+ return err;
+
+ atomic_set(profile_mode, !!value);
+
+ return count;
+}
+
+static const struct kobj_attribute profiling_status =
+__ATTR(status, 0644, profiling_show, profiling_store);
+
+static const struct kobj_type kobj_profile_type = {
+ .sysfs_ops = &kobj_sysfs_ops,
+};
+
+int panfrost_sysfs_init(struct panfrost_device *pfdev)
+{
+ struct device *kdev = pfdev->ddev->primary->kdev;
+ int err;
+
+ kobject_init(&pfdev->profiling.base, &kobj_profile_type);
+
+ err = kobject_add(&pfdev->profiling.base, &kdev->kobj, "%s", "profiling");
+ if (err)
+ return err;
+
+ err = sysfs_create_file(&pfdev->profiling.base, &profiling_status.attr);
+ if (err)
+ kobject_del(&pfdev->profiling.base);
+
+ return err;
+}
+
+void panfrost_sysfs_cleanup(struct panfrost_device *pfdev)
+{
+ sysfs_remove_file(&pfdev->profiling.base, &profiling_status.attr);
+ kobject_del(&pfdev->profiling.base);
+}
diff --git a/drivers/gpu/drm/panfrost/panfrost_sysfs.h b/drivers/gpu/drm/panfrost/panfrost_sysfs.h
new file mode 100644
index 000000000000..5fc9c8c1091a
--- /dev/null
+++ b/drivers/gpu/drm/panfrost/panfrost_sysfs.h
@@ -0,0 +1,15 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright 2023 Collabora ltd.
+ * Copyright 2023 Amazon.com, Inc. or its affiliates.
+ */
+
+#ifndef PANFROST_SYSFS_H
+#define PANFROST_SYSFS_H
+
+struct panfrost_device;
+
+int panfrost_sysfs_init(struct panfrost_device *pfdev);
+void panfrost_sysfs_cleanup(struct panfrost_device *pfdev);
+
+#endif /* PANFROST_SYSFS_H */
--
2.43.0
On 21/02/2024 16:12, Adrián Larumbe wrote:
> Debugfs isn't always available in production builds that try to squeeze
> every single byte out of the kernel image, but we still need a way to
> toggle the timestamp and cycle counter registers so that jobs can be
> profiled for fdinfo's drm engine and cycle calculations.
>
> Drop the debugfs knob and replace it with a sysfs file that accomplishes
> the same functionality, and document its ABI in a separate file.
>
> Signed-off-by: Adrián Larumbe <[email protected]>
> ---
> .../testing/sysfs-driver-panfrost-profiling | 10 +++
> Documentation/gpu/panfrost.rst | 9 +++
> drivers/gpu/drm/panfrost/Makefile | 5 +-
> drivers/gpu/drm/panfrost/panfrost_debugfs.c | 21 ------
> drivers/gpu/drm/panfrost/panfrost_debugfs.h | 14 ----
> drivers/gpu/drm/panfrost/panfrost_device.h | 5 +-
> drivers/gpu/drm/panfrost/panfrost_drv.c | 14 ++--
> drivers/gpu/drm/panfrost/panfrost_job.c | 2 +-
> drivers/gpu/drm/panfrost/panfrost_sysfs.c | 74 +++++++++++++++++++
> drivers/gpu/drm/panfrost/panfrost_sysfs.h | 15 ++++
> 10 files changed, 124 insertions(+), 45 deletions(-)
> create mode 100644 Documentation/ABI/testing/sysfs-driver-panfrost-profiling
> delete mode 100644 drivers/gpu/drm/panfrost/panfrost_debugfs.c
> delete mode 100644 drivers/gpu/drm/panfrost/panfrost_debugfs.h
> create mode 100644 drivers/gpu/drm/panfrost/panfrost_sysfs.c
> create mode 100644 drivers/gpu/drm/panfrost/panfrost_sysfs.h
>
> diff --git a/Documentation/ABI/testing/sysfs-driver-panfrost-profiling b/Documentation/ABI/testing/sysfs-driver-panfrost-profiling
> new file mode 100644
> index 000000000000..ce54069714f3
> --- /dev/null
> +++ b/Documentation/ABI/testing/sysfs-driver-panfrost-profiling
> @@ -0,0 +1,10 @@
> +What: /sys/bus/.../drivers/panfrost/.../drm/../profiling/status
> +Date: February 2024
> +KernelVersion: 6.8.0
> +Contact: Adrian Larumbe <[email protected]>
> +Description:
> + Get/set drm fdinfo's engine and cycles profiling status.
> + Valid values are:
> + 0: Disable fdinfo job profiling sources. This disables both the GPU's
> + timestamp and cycle counter registers.
> + 1: Enable the above.
Minor point, but if we're going to eventually come up with a generic way
of doing this, then we're going to have to think about backwards
compatibility for this sysfs file. I would expect in this new world '0'
would mean "default behaviour; off unless the new-fangled thing enables
profiling" and '1' means "force on".
In which case perhaps wording like the below would be clearer:
0: Don't enable fdinfo job profiling sources.
1: Enable fdinfo job profiling sources, this enables both the GPU's
timestamp and cycle counter registers.
Or am I being too picky over the wording ;)
One other small issue below...
> diff --git a/Documentation/gpu/panfrost.rst b/Documentation/gpu/panfrost.rst
> index b80e41f4b2c5..be4ac282ef63 100644
> --- a/Documentation/gpu/panfrost.rst
> +++ b/Documentation/gpu/panfrost.rst
> @@ -38,3 +38,12 @@ the currently possible format options:
>
> Possible `drm-engine-` key names are: `fragment`, and `vertex-tiler`.
> `drm-curfreq-` values convey the current operating frequency for that engine.
> +
> +Users must bear in mind that engine and cycle sampling are disabled by default,
> +because of power saving concerns. `fdinfo` users and benchmark applications which
> +query the fdinfo file must make sure to toggle the job profiling status of the
> +driver by writing into the appropriate sysfs node::
> +
> + echo <N> > /sys/bus/platform/drivers/panfrost/[a-f0-9]*.gpu/drm/card1/profiling
> +
> +Where `N` is either `0` or `1`, depending on the desired enablement status.
> diff --git a/drivers/gpu/drm/panfrost/Makefile b/drivers/gpu/drm/panfrost/Makefile
> index 2c01c1e7523e..6e718595d8a6 100644
> --- a/drivers/gpu/drm/panfrost/Makefile
> +++ b/drivers/gpu/drm/panfrost/Makefile
> @@ -10,8 +10,7 @@ panfrost-y := \
> panfrost_job.o \
> panfrost_mmu.o \
> panfrost_perfcnt.o \
> - panfrost_dump.o
> -
> -panfrost-$(CONFIG_DEBUG_FS) += panfrost_debugfs.o
> + panfrost_dump.o \
> + panfrost_sysfs.o
>
> obj-$(CONFIG_DRM_PANFROST) += panfrost.o
> diff --git a/drivers/gpu/drm/panfrost/panfrost_debugfs.c b/drivers/gpu/drm/panfrost/panfrost_debugfs.c
> deleted file mode 100644
> index 72d4286a6bf7..000000000000
> --- a/drivers/gpu/drm/panfrost/panfrost_debugfs.c
> +++ /dev/null
> @@ -1,21 +0,0 @@
> -// SPDX-License-Identifier: GPL-2.0
> -/* Copyright 2023 Collabora ltd. */
> -/* Copyright 2023 Amazon.com, Inc. or its affiliates. */
> -
> -#include <linux/debugfs.h>
> -#include <linux/platform_device.h>
> -#include <drm/drm_debugfs.h>
> -#include <drm/drm_file.h>
> -#include <drm/panfrost_drm.h>
> -
> -#include "panfrost_device.h"
> -#include "panfrost_gpu.h"
> -#include "panfrost_debugfs.h"
> -
> -void panfrost_debugfs_init(struct drm_minor *minor)
> -{
> - struct drm_device *dev = minor->dev;
> - struct panfrost_device *pfdev = platform_get_drvdata(to_platform_device(dev->dev));
> -
> - debugfs_create_atomic_t("profile", 0600, minor->debugfs_root, &pfdev->profile_mode);
> -}
> diff --git a/drivers/gpu/drm/panfrost/panfrost_debugfs.h b/drivers/gpu/drm/panfrost/panfrost_debugfs.h
> deleted file mode 100644
> index c5af5f35877f..000000000000
> --- a/drivers/gpu/drm/panfrost/panfrost_debugfs.h
> +++ /dev/null
> @@ -1,14 +0,0 @@
> -/* SPDX-License-Identifier: GPL-2.0 */
> -/*
> - * Copyright 2023 Collabora ltd.
> - * Copyright 2023 Amazon.com, Inc. or its affiliates.
> - */
> -
> -#ifndef PANFROST_DEBUGFS_H
> -#define PANFROST_DEBUGFS_H
> -
> -#ifdef CONFIG_DEBUG_FS
> -void panfrost_debugfs_init(struct drm_minor *minor);
> -#endif
> -
> -#endif /* PANFROST_DEBUGFS_H */
> diff --git a/drivers/gpu/drm/panfrost/panfrost_device.h b/drivers/gpu/drm/panfrost/panfrost_device.h
> index 62f7e3527385..56c8e5551335 100644
> --- a/drivers/gpu/drm/panfrost/panfrost_device.h
> +++ b/drivers/gpu/drm/panfrost/panfrost_device.h
> @@ -130,7 +130,10 @@ struct panfrost_device {
> struct list_head scheduled_jobs;
>
> struct panfrost_perfcnt *perfcnt;
> - atomic_t profile_mode;
> + struct kobj_profiling {
> + struct kobject base;
> + atomic_t profile_mode;
> + } profiling;
>
> struct mutex sched_lock;
>
> diff --git a/drivers/gpu/drm/panfrost/panfrost_drv.c b/drivers/gpu/drm/panfrost/panfrost_drv.c
> index a926d71e8131..6db1ea453514 100644
> --- a/drivers/gpu/drm/panfrost/panfrost_drv.c
> +++ b/drivers/gpu/drm/panfrost/panfrost_drv.c
> @@ -20,7 +20,7 @@
> #include "panfrost_job.h"
> #include "panfrost_gpu.h"
> #include "panfrost_perfcnt.h"
> -#include "panfrost_debugfs.h"
> +#include "panfrost_sysfs.h"
>
> static bool unstable_ioctls;
> module_param_unsafe(unstable_ioctls, bool, 0600);
> @@ -600,10 +600,6 @@ static const struct drm_driver panfrost_drm_driver = {
>
> .gem_create_object = panfrost_gem_create_object,
> .gem_prime_import_sg_table = panfrost_gem_prime_import_sg_table,
> -
> -#ifdef CONFIG_DEBUG_FS
> - .debugfs_init = panfrost_debugfs_init,
> -#endif
> };
>
> static int panfrost_probe(struct platform_device *pdev)
> @@ -663,8 +659,14 @@ static int panfrost_probe(struct platform_device *pdev)
> if (err)
> goto err_out2;
>
> + err = panfrost_sysfs_init(pfdev);
> + if (err)
> + goto err_out3;
> +
> return 0;
>
> +err_out3:
> + panfrost_gem_shrinker_cleanup(ddev);
> err_out2:
> drm_dev_unregister(ddev);
> err_out1:
> @@ -681,6 +683,8 @@ static void panfrost_remove(struct platform_device *pdev)
> struct panfrost_device *pfdev = platform_get_drvdata(pdev);
> struct drm_device *ddev = pfdev->ddev;
>
> + panfrost_sysfs_cleanup(pfdev);
> +
> drm_dev_unregister(ddev);
> panfrost_gem_shrinker_cleanup(ddev);
>
> diff --git a/drivers/gpu/drm/panfrost/panfrost_job.c b/drivers/gpu/drm/panfrost/panfrost_job.c
> index 0c2dbf6ef2a5..49413dfda2ea 100644
> --- a/drivers/gpu/drm/panfrost/panfrost_job.c
> +++ b/drivers/gpu/drm/panfrost/panfrost_job.c
> @@ -243,7 +243,7 @@ static void panfrost_job_hw_submit(struct panfrost_job *job, int js)
> subslot = panfrost_enqueue_job(pfdev, js, job);
> /* Don't queue the job if a reset is in progress */
> if (!atomic_read(&pfdev->reset.pending)) {
> - if (atomic_read(&pfdev->profile_mode)) {
> + if (atomic_read(&pfdev->profiling.profile_mode)) {
> panfrost_cycle_counter_get(pfdev);
> job->is_profiled = true;
> job->start_time = ktime_get();
> diff --git a/drivers/gpu/drm/panfrost/panfrost_sysfs.c b/drivers/gpu/drm/panfrost/panfrost_sysfs.c
> new file mode 100644
> index 000000000000..072d3bf349d2
> --- /dev/null
> +++ b/drivers/gpu/drm/panfrost/panfrost_sysfs.c
> @@ -0,0 +1,74 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/* Copyright 2023 Collabora ltd. */
> +/* Copyright 2023 Amazon.com, Inc. or its affiliates. */
> +
> +#include <linux/platform_device.h>
> +#include <drm/drm_file.h>
> +#include <drm/panfrost_drm.h>
> +
> +#include "panfrost_device.h"
> +#include "panfrost_gpu.h"
> +#include "panfrost_sysfs.h"
> +
> +static ssize_t
> +profiling_show(struct kobject *kobj, struct kobj_attribute *attr, char *buf)
> +{
> + atomic_t *profile_mode =
> + &container_of(kobj, struct {
> + struct kobject base;
> + atomic_t profile_mode; },
> + base)->profile_mode;
Yuck! ;) That's likely to catch people out if they modify the struct in
the header file.
Why not "struct kobj_profiling" rather than that inline struct. I'd also
argue that kobj_profiling isn't a great name and I'd suggest something
with 'panfrost' in the name. Or you could just use the parent struct
panfrost_device and not bother naming this sub-struct, e.g.
&container_of(kobj, struct panfrost_device,
profiling.base)->profiling.profile_mode;
Thanks,
Steve
> +
> + return sysfs_emit(buf, "%d\n", atomic_read(profile_mode));
> +}
> +
> +static ssize_t
> +profiling_store(struct kobject *kobj, struct kobj_attribute *attr,
> + const char *buf, size_t count)
> +{
> + atomic_t *profile_mode =
> + &container_of(kobj, struct {
> + struct kobject base;
> + atomic_t profile_mode; },
> + base)->profile_mode;
> + int err, value;
> +
> + err = kstrtoint(buf, 0, &value);
> + if (err)
> + return err;
> +
> + atomic_set(profile_mode, !!value);
> +
> + return count;
> +}
> +
> +static const struct kobj_attribute profiling_status =
> +__ATTR(status, 0644, profiling_show, profiling_store);
> +
> +static const struct kobj_type kobj_profile_type = {
> + .sysfs_ops = &kobj_sysfs_ops,
> +};
> +
> +int panfrost_sysfs_init(struct panfrost_device *pfdev)
> +{
> + struct device *kdev = pfdev->ddev->primary->kdev;
> + int err;
> +
> + kobject_init(&pfdev->profiling.base, &kobj_profile_type);
> +
> + err = kobject_add(&pfdev->profiling.base, &kdev->kobj, "%s", "profiling");
> + if (err)
> + return err;
> +
> + err = sysfs_create_file(&pfdev->profiling.base, &profiling_status.attr);
> + if (err)
> + kobject_del(&pfdev->profiling.base);
> +
> + return err;
> +}
> +
> +void panfrost_sysfs_cleanup(struct panfrost_device *pfdev)
> +{
> + sysfs_remove_file(&pfdev->profiling.base, &profiling_status.attr);
> + kobject_del(&pfdev->profiling.base);
> +}
> diff --git a/drivers/gpu/drm/panfrost/panfrost_sysfs.h b/drivers/gpu/drm/panfrost/panfrost_sysfs.h
> new file mode 100644
> index 000000000000..5fc9c8c1091a
> --- /dev/null
> +++ b/drivers/gpu/drm/panfrost/panfrost_sysfs.h
> @@ -0,0 +1,15 @@
> +/* SPDX-License-Identifier: GPL-2.0 */
> +/*
> + * Copyright 2023 Collabora ltd.
> + * Copyright 2023 Amazon.com, Inc. or its affiliates.
> + */
> +
> +#ifndef PANFROST_SYSFS_H
> +#define PANFROST_SYSFS_H
> +
> +struct panfrost_device;
> +
> +int panfrost_sysfs_init(struct panfrost_device *pfdev);
> +void panfrost_sysfs_cleanup(struct panfrost_device *pfdev);
> +
> +#endif /* PANFROST_SYSFS_H */
On Wed, 21 Feb 2024 16:12:32 +0000
Adrián Larumbe <[email protected]> wrote:
> Debugfs isn't always available in production builds that try to squeeze
> every single byte out of the kernel image, but we still need a way to
> toggle the timestamp and cycle counter registers so that jobs can be
> profiled for fdinfo's drm engine and cycle calculations.
>
> Drop the debugfs knob and replace it with a sysfs file that accomplishes
> the same functionality, and document its ABI in a separate file.
>
> Signed-off-by: Adrián Larumbe <[email protected]>
> ---
> .../testing/sysfs-driver-panfrost-profiling | 10 +++
> Documentation/gpu/panfrost.rst | 9 +++
> drivers/gpu/drm/panfrost/Makefile | 5 +-
> drivers/gpu/drm/panfrost/panfrost_debugfs.c | 21 ------
> drivers/gpu/drm/panfrost/panfrost_debugfs.h | 14 ----
> drivers/gpu/drm/panfrost/panfrost_device.h | 5 +-
> drivers/gpu/drm/panfrost/panfrost_drv.c | 14 ++--
> drivers/gpu/drm/panfrost/panfrost_job.c | 2 +-
> drivers/gpu/drm/panfrost/panfrost_sysfs.c | 74 +++++++++++++++++++
> drivers/gpu/drm/panfrost/panfrost_sysfs.h | 15 ++++
> 10 files changed, 124 insertions(+), 45 deletions(-)
> create mode 100644 Documentation/ABI/testing/sysfs-driver-panfrost-profiling
> delete mode 100644 drivers/gpu/drm/panfrost/panfrost_debugfs.c
> delete mode 100644 drivers/gpu/drm/panfrost/panfrost_debugfs.h
> create mode 100644 drivers/gpu/drm/panfrost/panfrost_sysfs.c
> create mode 100644 drivers/gpu/drm/panfrost/panfrost_sysfs.h
>
> diff --git a/Documentation/ABI/testing/sysfs-driver-panfrost-profiling b/Documentation/ABI/testing/sysfs-driver-panfrost-profiling
> new file mode 100644
> index 000000000000..ce54069714f3
> --- /dev/null
> +++ b/Documentation/ABI/testing/sysfs-driver-panfrost-profiling
> @@ -0,0 +1,10 @@
> +What: /sys/bus/.../drivers/panfrost/.../drm/../profiling/status
> +Date: February 2024
> +KernelVersion: 6.8.0
> +Contact: Adrian Larumbe <[email protected]>
> +Description:
> + Get/set drm fdinfo's engine and cycles profiling status.
> + Valid values are:
> + 0: Disable fdinfo job profiling sources. This disables both the GPU's
> + timestamp and cycle counter registers.
> + 1: Enable the above.
> diff --git a/Documentation/gpu/panfrost.rst b/Documentation/gpu/panfrost.rst
> index b80e41f4b2c5..be4ac282ef63 100644
> --- a/Documentation/gpu/panfrost.rst
> +++ b/Documentation/gpu/panfrost.rst
> @@ -38,3 +38,12 @@ the currently possible format options:
>
> Possible `drm-engine-` key names are: `fragment`, and `vertex-tiler`.
> `drm-curfreq-` values convey the current operating frequency for that engine.
> +
> +Users must bear in mind that engine and cycle sampling are disabled by default,
> +because of power saving concerns. `fdinfo` users and benchmark applications which
> +query the fdinfo file must make sure to toggle the job profiling status of the
> +driver by writing into the appropriate sysfs node::
> +
> + echo <N> > /sys/bus/platform/drivers/panfrost/[a-f0-9]*.gpu/drm/card1/profiling
> +
> +Where `N` is either `0` or `1`, depending on the desired enablement status.
> diff --git a/drivers/gpu/drm/panfrost/Makefile b/drivers/gpu/drm/panfrost/Makefile
> index 2c01c1e7523e..6e718595d8a6 100644
> --- a/drivers/gpu/drm/panfrost/Makefile
> +++ b/drivers/gpu/drm/panfrost/Makefile
> @@ -10,8 +10,7 @@ panfrost-y := \
> panfrost_job.o \
> panfrost_mmu.o \
> panfrost_perfcnt.o \
> - panfrost_dump.o
> -
> -panfrost-$(CONFIG_DEBUG_FS) += panfrost_debugfs.o
> + panfrost_dump.o \
> + panfrost_sysfs.o
>
> obj-$(CONFIG_DRM_PANFROST) += panfrost.o
> diff --git a/drivers/gpu/drm/panfrost/panfrost_debugfs.c b/drivers/gpu/drm/panfrost/panfrost_debugfs.c
> deleted file mode 100644
> index 72d4286a6bf7..000000000000
> --- a/drivers/gpu/drm/panfrost/panfrost_debugfs.c
> +++ /dev/null
> @@ -1,21 +0,0 @@
> -// SPDX-License-Identifier: GPL-2.0
> -/* Copyright 2023 Collabora ltd. */
> -/* Copyright 2023 Amazon.com, Inc. or its affiliates. */
> -
> -#include <linux/debugfs.h>
> -#include <linux/platform_device.h>
> -#include <drm/drm_debugfs.h>
> -#include <drm/drm_file.h>
> -#include <drm/panfrost_drm.h>
> -
> -#include "panfrost_device.h"
> -#include "panfrost_gpu.h"
> -#include "panfrost_debugfs.h"
> -
> -void panfrost_debugfs_init(struct drm_minor *minor)
> -{
> - struct drm_device *dev = minor->dev;
> - struct panfrost_device *pfdev = platform_get_drvdata(to_platform_device(dev->dev));
> -
> - debugfs_create_atomic_t("profile", 0600, minor->debugfs_root, &pfdev->profile_mode);
> -}
> diff --git a/drivers/gpu/drm/panfrost/panfrost_debugfs.h b/drivers/gpu/drm/panfrost/panfrost_debugfs.h
> deleted file mode 100644
> index c5af5f35877f..000000000000
> --- a/drivers/gpu/drm/panfrost/panfrost_debugfs.h
> +++ /dev/null
> @@ -1,14 +0,0 @@
> -/* SPDX-License-Identifier: GPL-2.0 */
> -/*
> - * Copyright 2023 Collabora ltd.
> - * Copyright 2023 Amazon.com, Inc. or its affiliates.
> - */
> -
> -#ifndef PANFROST_DEBUGFS_H
> -#define PANFROST_DEBUGFS_H
> -
> -#ifdef CONFIG_DEBUG_FS
> -void panfrost_debugfs_init(struct drm_minor *minor);
> -#endif
> -
> -#endif /* PANFROST_DEBUGFS_H */
> diff --git a/drivers/gpu/drm/panfrost/panfrost_device.h b/drivers/gpu/drm/panfrost/panfrost_device.h
> index 62f7e3527385..56c8e5551335 100644
> --- a/drivers/gpu/drm/panfrost/panfrost_device.h
> +++ b/drivers/gpu/drm/panfrost/panfrost_device.h
> @@ -130,7 +130,10 @@ struct panfrost_device {
> struct list_head scheduled_jobs;
>
> struct panfrost_perfcnt *perfcnt;
> - atomic_t profile_mode;
> + struct kobj_profiling {
> + struct kobject base;
> + atomic_t profile_mode;
> + } profiling;
>
> struct mutex sched_lock;
>
> diff --git a/drivers/gpu/drm/panfrost/panfrost_drv.c b/drivers/gpu/drm/panfrost/panfrost_drv.c
> index a926d71e8131..6db1ea453514 100644
> --- a/drivers/gpu/drm/panfrost/panfrost_drv.c
> +++ b/drivers/gpu/drm/panfrost/panfrost_drv.c
> @@ -20,7 +20,7 @@
> #include "panfrost_job.h"
> #include "panfrost_gpu.h"
> #include "panfrost_perfcnt.h"
> -#include "panfrost_debugfs.h"
> +#include "panfrost_sysfs.h"
>
> static bool unstable_ioctls;
> module_param_unsafe(unstable_ioctls, bool, 0600);
> @@ -600,10 +600,6 @@ static const struct drm_driver panfrost_drm_driver = {
>
> .gem_create_object = panfrost_gem_create_object,
> .gem_prime_import_sg_table = panfrost_gem_prime_import_sg_table,
> -
> -#ifdef CONFIG_DEBUG_FS
> - .debugfs_init = panfrost_debugfs_init,
> -#endif
> };
>
> static int panfrost_probe(struct platform_device *pdev)
> @@ -663,8 +659,14 @@ static int panfrost_probe(struct platform_device *pdev)
> if (err)
> goto err_out2;
>
> + err = panfrost_sysfs_init(pfdev);
> + if (err)
> + goto err_out3;
> +
> return 0;
>
> +err_out3:
> + panfrost_gem_shrinker_cleanup(ddev);
> err_out2:
> drm_dev_unregister(ddev);
> err_out1:
> @@ -681,6 +683,8 @@ static void panfrost_remove(struct platform_device *pdev)
> struct panfrost_device *pfdev = platform_get_drvdata(pdev);
> struct drm_device *ddev = pfdev->ddev;
>
> + panfrost_sysfs_cleanup(pfdev);
> +
> drm_dev_unregister(ddev);
> panfrost_gem_shrinker_cleanup(ddev);
>
> diff --git a/drivers/gpu/drm/panfrost/panfrost_job.c b/drivers/gpu/drm/panfrost/panfrost_job.c
> index 0c2dbf6ef2a5..49413dfda2ea 100644
> --- a/drivers/gpu/drm/panfrost/panfrost_job.c
> +++ b/drivers/gpu/drm/panfrost/panfrost_job.c
> @@ -243,7 +243,7 @@ static void panfrost_job_hw_submit(struct panfrost_job *job, int js)
> subslot = panfrost_enqueue_job(pfdev, js, job);
> /* Don't queue the job if a reset is in progress */
> if (!atomic_read(&pfdev->reset.pending)) {
> - if (atomic_read(&pfdev->profile_mode)) {
> + if (atomic_read(&pfdev->profiling.profile_mode)) {
> panfrost_cycle_counter_get(pfdev);
> job->is_profiled = true;
> job->start_time = ktime_get();
> diff --git a/drivers/gpu/drm/panfrost/panfrost_sysfs.c b/drivers/gpu/drm/panfrost/panfrost_sysfs.c
> new file mode 100644
> index 000000000000..072d3bf349d2
> --- /dev/null
> +++ b/drivers/gpu/drm/panfrost/panfrost_sysfs.c
> @@ -0,0 +1,74 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/* Copyright 2023 Collabora ltd. */
> +/* Copyright 2023 Amazon.com, Inc. or its affiliates. */
> +
> +#include <linux/platform_device.h>
> +#include <drm/drm_file.h>
> +#include <drm/panfrost_drm.h>
> +
> +#include "panfrost_device.h"
> +#include "panfrost_gpu.h"
> +#include "panfrost_sysfs.h"
> +
> +static ssize_t
> +profiling_show(struct kobject *kobj, struct kobj_attribute *attr, char *buf)
> +{
> + atomic_t *profile_mode =
> + &container_of(kobj, struct {
> + struct kobject base;
> + atomic_t profile_mode; },
> + base)->profile_mode;
> +
> + return sysfs_emit(buf, "%d\n", atomic_read(profile_mode));
> +}
> +
> +static ssize_t
> +profiling_store(struct kobject *kobj, struct kobj_attribute *attr,
> + const char *buf, size_t count)
> +{
> + atomic_t *profile_mode =
> + &container_of(kobj, struct {
> + struct kobject base;
> + atomic_t profile_mode; },
> + base)->profile_mode;
> + int err, value;
Can't we just make this a RW module_param to simplify things? I fail to
see why we need an atomic here since active cycle-count users are
already tracked with an atomic_t that's incremented/decremented
everytime a job is submitted/considered done.
> +
> + err = kstrtoint(buf, 0, &value);
> + if (err)
> + return err;
> +
> + atomic_set(profile_mode, !!value);
> +
> + return count;
> +}
> +
> +static const struct kobj_attribute profiling_status =
> +__ATTR(status, 0644, profiling_show, profiling_store);
> +
> +static const struct kobj_type kobj_profile_type = {
> + .sysfs_ops = &kobj_sysfs_ops,
> +};
> +
> +int panfrost_sysfs_init(struct panfrost_device *pfdev)
> +{
> + struct device *kdev = pfdev->ddev->primary->kdev;
> + int err;
> +
> + kobject_init(&pfdev->profiling.base, &kobj_profile_type);
> +
> + err = kobject_add(&pfdev->profiling.base, &kdev->kobj, "%s", "profiling");
> + if (err)
> + return err;
> +
> + err = sysfs_create_file(&pfdev->profiling.base, &profiling_status.attr);
> + if (err)
> + kobject_del(&pfdev->profiling.base);
> +
> + return err;
> +}
> +
> +void panfrost_sysfs_cleanup(struct panfrost_device *pfdev)
> +{
> + sysfs_remove_file(&pfdev->profiling.base, &profiling_status.attr);
> + kobject_del(&pfdev->profiling.base);
> +}
> diff --git a/drivers/gpu/drm/panfrost/panfrost_sysfs.h b/drivers/gpu/drm/panfrost/panfrost_sysfs.h
> new file mode 100644
> index 000000000000..5fc9c8c1091a
> --- /dev/null
> +++ b/drivers/gpu/drm/panfrost/panfrost_sysfs.h
> @@ -0,0 +1,15 @@
> +/* SPDX-License-Identifier: GPL-2.0 */
> +/*
> + * Copyright 2023 Collabora ltd.
> + * Copyright 2023 Amazon.com, Inc. or its affiliates.
> + */
> +
> +#ifndef PANFROST_SYSFS_H
> +#define PANFROST_SYSFS_H
> +
> +struct panfrost_device;
> +
> +int panfrost_sysfs_init(struct panfrost_device *pfdev);
> +void panfrost_sysfs_cleanup(struct panfrost_device *pfdev);
> +
> +#endif /* PANFROST_SYSFS_H */
Hi Steve,
On 21.02.2024 16:52, Steven Price wrote:
> On 21/02/2024 16:12, Adrián Larumbe wrote:
> > Debugfs isn't always available in production builds that try to squeeze
> > every single byte out of the kernel image, but we still need a way to
> > toggle the timestamp and cycle counter registers so that jobs can be
> > profiled for fdinfo's drm engine and cycle calculations.
> >
> > Drop the debugfs knob and replace it with a sysfs file that accomplishes
> > the same functionality, and document its ABI in a separate file.
> >
> > Signed-off-by: Adrián Larumbe <[email protected]>
> > ---
> > .../testing/sysfs-driver-panfrost-profiling | 10 +++
> > Documentation/gpu/panfrost.rst | 9 +++
> > drivers/gpu/drm/panfrost/Makefile | 5 +-
> > drivers/gpu/drm/panfrost/panfrost_debugfs.c | 21 ------
> > drivers/gpu/drm/panfrost/panfrost_debugfs.h | 14 ----
> > drivers/gpu/drm/panfrost/panfrost_device.h | 5 +-
> > drivers/gpu/drm/panfrost/panfrost_drv.c | 14 ++--
> > drivers/gpu/drm/panfrost/panfrost_job.c | 2 +-
> > drivers/gpu/drm/panfrost/panfrost_sysfs.c | 74 +++++++++++++++++++
> > drivers/gpu/drm/panfrost/panfrost_sysfs.h | 15 ++++
> > 10 files changed, 124 insertions(+), 45 deletions(-)
> > create mode 100644 Documentation/ABI/testing/sysfs-driver-panfrost-profiling
> > delete mode 100644 drivers/gpu/drm/panfrost/panfrost_debugfs.c
> > delete mode 100644 drivers/gpu/drm/panfrost/panfrost_debugfs.h
> > create mode 100644 drivers/gpu/drm/panfrost/panfrost_sysfs.c
> > create mode 100644 drivers/gpu/drm/panfrost/panfrost_sysfs.h
> >
> > diff --git a/Documentation/ABI/testing/sysfs-driver-panfrost-profiling b/Documentation/ABI/testing/sysfs-driver-panfrost-profiling
> > new file mode 100644
> > index 000000000000..ce54069714f3
> > --- /dev/null
> > +++ b/Documentation/ABI/testing/sysfs-driver-panfrost-profiling
> > @@ -0,0 +1,10 @@
> > +What: /sys/bus/.../drivers/panfrost/.../drm/../profiling/status
> > +Date: February 2024
> > +KernelVersion: 6.8.0
> > +Contact: Adrian Larumbe <[email protected]>
> > +Description:
> > + Get/set drm fdinfo's engine and cycles profiling status.
> > + Valid values are:
> > + 0: Disable fdinfo job profiling sources. This disables both the GPU's
> > + timestamp and cycle counter registers.
> > + 1: Enable the above.
>
> Minor point, but if we're going to eventually come up with a generic way
> of doing this, then we're going to have to think about backwards
> compatibility for this sysfs file. I would expect in this new world '0'
> would mean "default behaviour; off unless the new-fangled thing enables
> profiling" and '1' means "force on".
>
> In which case perhaps wording like the below would be clearer:
>
> 0: Don't enable fdinfo job profiling sources.
> 1: Enable fdinfo job profiling sources, this enables both the GPU's
> timestamp and cycle counter registers.
>
> Or am I being too picky over the wording ;)
I'm alright with this kind of wording, to keep things as generic as
possible. Initially I thought just mentioning 0 and 1 as potential toggle values
would be enough, and then every driver could describe their own profiling/status
sysfs knob in similar terms, depending on what profiling resouces they act upon.
> One other small issue below...
>
> > diff --git a/Documentation/gpu/panfrost.rst b/Documentation/gpu/panfrost.rst
> > index b80e41f4b2c5..be4ac282ef63 100644
> > --- a/Documentation/gpu/panfrost.rst
> > +++ b/Documentation/gpu/panfrost.rst
> > @@ -38,3 +38,12 @@ the currently possible format options:
> >
> > Possible `drm-engine-` key names are: `fragment`, and `vertex-tiler`.
> > `drm-curfreq-` values convey the current operating frequency for that engine.
> > +
> > +Users must bear in mind that engine and cycle sampling are disabled by default,
> > +because of power saving concerns. `fdinfo` users and benchmark applications which
> > +query the fdinfo file must make sure to toggle the job profiling status of the
> > +driver by writing into the appropriate sysfs node::
> > +
> > + echo <N> > /sys/bus/platform/drivers/panfrost/[a-f0-9]*.gpu/drm/card1/profiling
> > +
> > +Where `N` is either `0` or `1`, depending on the desired enablement status.
> > diff --git a/drivers/gpu/drm/panfrost/Makefile b/drivers/gpu/drm/panfrost/Makefile
> > index 2c01c1e7523e..6e718595d8a6 100644
> > --- a/drivers/gpu/drm/panfrost/Makefile
> > +++ b/drivers/gpu/drm/panfrost/Makefile
> > @@ -10,8 +10,7 @@ panfrost-y := \
> > panfrost_job.o \
> > panfrost_mmu.o \
> > panfrost_perfcnt.o \
> > - panfrost_dump.o
> > -
> > -panfrost-$(CONFIG_DEBUG_FS) += panfrost_debugfs.o
> > + panfrost_dump.o \
> > + panfrost_sysfs.o
> >
> > obj-$(CONFIG_DRM_PANFROST) += panfrost.o
> > diff --git a/drivers/gpu/drm/panfrost/panfrost_debugfs.c b/drivers/gpu/drm/panfrost/panfrost_debugfs.c
> > deleted file mode 100644
> > index 72d4286a6bf7..000000000000
> > --- a/drivers/gpu/drm/panfrost/panfrost_debugfs.c
> > +++ /dev/null
> > @@ -1,21 +0,0 @@
> > -// SPDX-License-Identifier: GPL-2.0
> > -/* Copyright 2023 Collabora ltd. */
> > -/* Copyright 2023 Amazon.com, Inc. or its affiliates. */
> > -
> > -#include <linux/debugfs.h>
> > -#include <linux/platform_device.h>
> > -#include <drm/drm_debugfs.h>
> > -#include <drm/drm_file.h>
> > -#include <drm/panfrost_drm.h>
> > -
> > -#include "panfrost_device.h"
> > -#include "panfrost_gpu.h"
> > -#include "panfrost_debugfs.h"
> > -
> > -void panfrost_debugfs_init(struct drm_minor *minor)
> > -{
> > - struct drm_device *dev = minor->dev;
> > - struct panfrost_device *pfdev = platform_get_drvdata(to_platform_device(dev->dev));
> > -
> > - debugfs_create_atomic_t("profile", 0600, minor->debugfs_root, &pfdev->profile_mode);
> > -}
> > diff --git a/drivers/gpu/drm/panfrost/panfrost_debugfs.h b/drivers/gpu/drm/panfrost/panfrost_debugfs.h
> > deleted file mode 100644
> > index c5af5f35877f..000000000000
> > --- a/drivers/gpu/drm/panfrost/panfrost_debugfs.h
> > +++ /dev/null
> > @@ -1,14 +0,0 @@
> > -/* SPDX-License-Identifier: GPL-2.0 */
> > -/*
> > - * Copyright 2023 Collabora ltd.
> > - * Copyright 2023 Amazon.com, Inc. or its affiliates.
> > - */
> > -
> > -#ifndef PANFROST_DEBUGFS_H
> > -#define PANFROST_DEBUGFS_H
> > -
> > -#ifdef CONFIG_DEBUG_FS
> > -void panfrost_debugfs_init(struct drm_minor *minor);
> > -#endif
> > -
> > -#endif /* PANFROST_DEBUGFS_H */
> > diff --git a/drivers/gpu/drm/panfrost/panfrost_device.h b/drivers/gpu/drm/panfrost/panfrost_device.h
> > index 62f7e3527385..56c8e5551335 100644
> > --- a/drivers/gpu/drm/panfrost/panfrost_device.h
> > +++ b/drivers/gpu/drm/panfrost/panfrost_device.h
> > @@ -130,7 +130,10 @@ struct panfrost_device {
> > struct list_head scheduled_jobs;
> >
> > struct panfrost_perfcnt *perfcnt;
> > - atomic_t profile_mode;
> > + struct kobj_profiling {
> > + struct kobject base;
> > + atomic_t profile_mode;
> > + } profiling;
> >
> > struct mutex sched_lock;
> >
> > diff --git a/drivers/gpu/drm/panfrost/panfrost_drv.c b/drivers/gpu/drm/panfrost/panfrost_drv.c
> > index a926d71e8131..6db1ea453514 100644
> > --- a/drivers/gpu/drm/panfrost/panfrost_drv.c
> > +++ b/drivers/gpu/drm/panfrost/panfrost_drv.c
> > @@ -20,7 +20,7 @@
> > #include "panfrost_job.h"
> > #include "panfrost_gpu.h"
> > #include "panfrost_perfcnt.h"
> > -#include "panfrost_debugfs.h"
> > +#include "panfrost_sysfs.h"
> >
> > static bool unstable_ioctls;
> > module_param_unsafe(unstable_ioctls, bool, 0600);
> > @@ -600,10 +600,6 @@ static const struct drm_driver panfrost_drm_driver = {
> >
> > .gem_create_object = panfrost_gem_create_object,
> > .gem_prime_import_sg_table = panfrost_gem_prime_import_sg_table,
> > -
> > -#ifdef CONFIG_DEBUG_FS
> > - .debugfs_init = panfrost_debugfs_init,
> > -#endif
> > };
> >
> > static int panfrost_probe(struct platform_device *pdev)
> > @@ -663,8 +659,14 @@ static int panfrost_probe(struct platform_device *pdev)
> > if (err)
> > goto err_out2;
> >
> > + err = panfrost_sysfs_init(pfdev);
> > + if (err)
> > + goto err_out3;
> > +
> > return 0;
> >
> > +err_out3:
> > + panfrost_gem_shrinker_cleanup(ddev);
> > err_out2:
> > drm_dev_unregister(ddev);
> > err_out1:
> > @@ -681,6 +683,8 @@ static void panfrost_remove(struct platform_device *pdev)
> > struct panfrost_device *pfdev = platform_get_drvdata(pdev);
> > struct drm_device *ddev = pfdev->ddev;
> >
> > + panfrost_sysfs_cleanup(pfdev);
> > +
> > drm_dev_unregister(ddev);
> > panfrost_gem_shrinker_cleanup(ddev);
> >
> > diff --git a/drivers/gpu/drm/panfrost/panfrost_job.c b/drivers/gpu/drm/panfrost/panfrost_job.c
> > index 0c2dbf6ef2a5..49413dfda2ea 100644
> > --- a/drivers/gpu/drm/panfrost/panfrost_job.c
> > +++ b/drivers/gpu/drm/panfrost/panfrost_job.c
> > @@ -243,7 +243,7 @@ static void panfrost_job_hw_submit(struct panfrost_job *job, int js)
> > subslot = panfrost_enqueue_job(pfdev, js, job);
> > /* Don't queue the job if a reset is in progress */
> > if (!atomic_read(&pfdev->reset.pending)) {
> > - if (atomic_read(&pfdev->profile_mode)) {
> > + if (atomic_read(&pfdev->profiling.profile_mode)) {
> > panfrost_cycle_counter_get(pfdev);
> > job->is_profiled = true;
> > job->start_time = ktime_get();
> > diff --git a/drivers/gpu/drm/panfrost/panfrost_sysfs.c b/drivers/gpu/drm/panfrost/panfrost_sysfs.c
> > new file mode 100644
> > index 000000000000..072d3bf349d2
> > --- /dev/null
> > +++ b/drivers/gpu/drm/panfrost/panfrost_sysfs.c
> > @@ -0,0 +1,74 @@
> > +// SPDX-License-Identifier: GPL-2.0
> > +/* Copyright 2023 Collabora ltd. */
> > +/* Copyright 2023 Amazon.com, Inc. or its affiliates. */
> > +
> > +#include <linux/platform_device.h>
> > +#include <drm/drm_file.h>
> > +#include <drm/panfrost_drm.h>
> > +
> > +#include "panfrost_device.h"
> > +#include "panfrost_gpu.h"
> > +#include "panfrost_sysfs.h"
> > +
> > +static ssize_t
> > +profiling_show(struct kobject *kobj, struct kobj_attribute *attr, char *buf)
> > +{
> > + atomic_t *profile_mode =
> > + &container_of(kobj, struct {
> > + struct kobject base;
> > + atomic_t profile_mode; },
> > + base)->profile_mode;
>
> Yuck! ;) That's likely to catch people out if they modify the struct in
> the header file.
Sorry about this abomination. I think it slipped through the cracks after a
first patch draft in which I didn't want to make the kobject-holding structure a
global declaration.
> Why not "struct kobj_profiling" rather than that inline struct. I'd also
> argue that kobj_profiling isn't a great name and I'd suggest something
> with 'panfrost' in the name. Or you could just use the parent struct
> panfrost_device and not bother naming this sub-struct, e.g.
>
> &container_of(kobj, struct panfrost_device,
> profiling.base)->profiling.profile_mode;
This is a much better way of doing things than mine. Thanks!
> Thanks,
> Steve
>
> > +
> > + return sysfs_emit(buf, "%d\n", atomic_read(profile_mode));
> > +}
> > +
> > +static ssize_t
> > +profiling_store(struct kobject *kobj, struct kobj_attribute *attr,
> > + const char *buf, size_t count)
> > +{
> > + atomic_t *profile_mode =
> > + &container_of(kobj, struct {
> > + struct kobject base;
> > + atomic_t profile_mode; },
> > + base)->profile_mode;
> > + int err, value;
> > +
> > + err = kstrtoint(buf, 0, &value);
> > + if (err)
> > + return err;
> > +
> > + atomic_set(profile_mode, !!value);
> > +
> > + return count;
> > +}
> > +
> > +static const struct kobj_attribute profiling_status =
> > +__ATTR(status, 0644, profiling_show, profiling_store);
> > +
> > +static const struct kobj_type kobj_profile_type = {
> > + .sysfs_ops = &kobj_sysfs_ops,
> > +};
> > +
> > +int panfrost_sysfs_init(struct panfrost_device *pfdev)
> > +{
> > + struct device *kdev = pfdev->ddev->primary->kdev;
> > + int err;
> > +
> > + kobject_init(&pfdev->profiling.base, &kobj_profile_type);
> > +
> > + err = kobject_add(&pfdev->profiling.base, &kdev->kobj, "%s", "profiling");
> > + if (err)
> > + return err;
> > +
> > + err = sysfs_create_file(&pfdev->profiling.base, &profiling_status.attr);
> > + if (err)
> > + kobject_del(&pfdev->profiling.base);
> > +
> > + return err;
> > +}
> > +
> > +void panfrost_sysfs_cleanup(struct panfrost_device *pfdev)
> > +{
> > + sysfs_remove_file(&pfdev->profiling.base, &profiling_status.attr);
> > + kobject_del(&pfdev->profiling.base);
> > +}
> > diff --git a/drivers/gpu/drm/panfrost/panfrost_sysfs.h b/drivers/gpu/drm/panfrost/panfrost_sysfs.h
> > new file mode 100644
> > index 000000000000..5fc9c8c1091a
> > --- /dev/null
> > +++ b/drivers/gpu/drm/panfrost/panfrost_sysfs.h
> > @@ -0,0 +1,15 @@
> > +/* SPDX-License-Identifier: GPL-2.0 */
> > +/*
> > + * Copyright 2023 Collabora ltd.
> > + * Copyright 2023 Amazon.com, Inc. or its affiliates.
> > + */
> > +
> > +#ifndef PANFROST_SYSFS_H
> > +#define PANFROST_SYSFS_H
> > +
> > +struct panfrost_device;
> > +
> > +int panfrost_sysfs_init(struct panfrost_device *pfdev);
> > +void panfrost_sysfs_cleanup(struct panfrost_device *pfdev);
> > +
> > +#endif /* PANFROST_SYSFS_H */
Hi Boris,
On 26.02.2024 09:51, Boris Brezillon wrote:
> On Wed, 21 Feb 2024 16:12:32 +0000
> Adrián Larumbe <[email protected]> wrote:
>
> > Debugfs isn't always available in production builds that try to squeeze
> > every single byte out of the kernel image, but we still need a way to
> > toggle the timestamp and cycle counter registers so that jobs can be
> > profiled for fdinfo's drm engine and cycle calculations.
> >
> > Drop the debugfs knob and replace it with a sysfs file that accomplishes
> > the same functionality, and document its ABI in a separate file.
> >
> > Signed-off-by: Adrián Larumbe <[email protected]>
> > ---
> > .../testing/sysfs-driver-panfrost-profiling | 10 +++
> > Documentation/gpu/panfrost.rst | 9 +++
> > drivers/gpu/drm/panfrost/Makefile | 5 +-
> > drivers/gpu/drm/panfrost/panfrost_debugfs.c | 21 ------
> > drivers/gpu/drm/panfrost/panfrost_debugfs.h | 14 ----
> > drivers/gpu/drm/panfrost/panfrost_device.h | 5 +-
> > drivers/gpu/drm/panfrost/panfrost_drv.c | 14 ++--
> > drivers/gpu/drm/panfrost/panfrost_job.c | 2 +-
> > drivers/gpu/drm/panfrost/panfrost_sysfs.c | 74 +++++++++++++++++++
> > drivers/gpu/drm/panfrost/panfrost_sysfs.h | 15 ++++
> > 10 files changed, 124 insertions(+), 45 deletions(-)
> > create mode 100644 Documentation/ABI/testing/sysfs-driver-panfrost-profiling
> > delete mode 100644 drivers/gpu/drm/panfrost/panfrost_debugfs.c
> > delete mode 100644 drivers/gpu/drm/panfrost/panfrost_debugfs.h
> > create mode 100644 drivers/gpu/drm/panfrost/panfrost_sysfs.c
> > create mode 100644 drivers/gpu/drm/panfrost/panfrost_sysfs.h
> >
> > diff --git a/Documentation/ABI/testing/sysfs-driver-panfrost-profiling b/Documentation/ABI/testing/sysfs-driver-panfrost-profiling
> > new file mode 100644
> > index 000000000000..ce54069714f3
> > --- /dev/null
> > +++ b/Documentation/ABI/testing/sysfs-driver-panfrost-profiling
> > @@ -0,0 +1,10 @@
> > +What: /sys/bus/.../drivers/panfrost/.../drm/../profiling/status
> > +Date: February 2024
> > +KernelVersion: 6.8.0
> > +Contact: Adrian Larumbe <[email protected]>
> > +Description:
> > + Get/set drm fdinfo's engine and cycles profiling status.
> > + Valid values are:
> > + 0: Disable fdinfo job profiling sources. This disables both the GPU's
> > + timestamp and cycle counter registers.
> > + 1: Enable the above.
> > diff --git a/Documentation/gpu/panfrost.rst b/Documentation/gpu/panfrost.rst
> > index b80e41f4b2c5..be4ac282ef63 100644
> > --- a/Documentation/gpu/panfrost.rst
> > +++ b/Documentation/gpu/panfrost.rst
> > @@ -38,3 +38,12 @@ the currently possible format options:
> >
> > Possible `drm-engine-` key names are: `fragment`, and `vertex-tiler`.
> > `drm-curfreq-` values convey the current operating frequency for that engine.
> > +
> > +Users must bear in mind that engine and cycle sampling are disabled by default,
> > +because of power saving concerns. `fdinfo` users and benchmark applications which
> > +query the fdinfo file must make sure to toggle the job profiling status of the
> > +driver by writing into the appropriate sysfs node::
> > +
> > + echo <N> > /sys/bus/platform/drivers/panfrost/[a-f0-9]*.gpu/drm/card1/profiling
> > +
> > +Where `N` is either `0` or `1`, depending on the desired enablement status.
> > diff --git a/drivers/gpu/drm/panfrost/Makefile b/drivers/gpu/drm/panfrost/Makefile
> > index 2c01c1e7523e..6e718595d8a6 100644
> > --- a/drivers/gpu/drm/panfrost/Makefile
> > +++ b/drivers/gpu/drm/panfrost/Makefile
> > @@ -10,8 +10,7 @@ panfrost-y := \
> > panfrost_job.o \
> > panfrost_mmu.o \
> > panfrost_perfcnt.o \
> > - panfrost_dump.o
> > -
> > -panfrost-$(CONFIG_DEBUG_FS) += panfrost_debugfs.o
> > + panfrost_dump.o \
> > + panfrost_sysfs.o
> >
> > obj-$(CONFIG_DRM_PANFROST) += panfrost.o
> > diff --git a/drivers/gpu/drm/panfrost/panfrost_debugfs.c b/drivers/gpu/drm/panfrost/panfrost_debugfs.c
> > deleted file mode 100644
> > index 72d4286a6bf7..000000000000
> > --- a/drivers/gpu/drm/panfrost/panfrost_debugfs.c
> > +++ /dev/null
> > @@ -1,21 +0,0 @@
> > -// SPDX-License-Identifier: GPL-2.0
> > -/* Copyright 2023 Collabora ltd. */
> > -/* Copyright 2023 Amazon.com, Inc. or its affiliates. */
> > -
> > -#include <linux/debugfs.h>
> > -#include <linux/platform_device.h>
> > -#include <drm/drm_debugfs.h>
> > -#include <drm/drm_file.h>
> > -#include <drm/panfrost_drm.h>
> > -
> > -#include "panfrost_device.h"
> > -#include "panfrost_gpu.h"
> > -#include "panfrost_debugfs.h"
> > -
> > -void panfrost_debugfs_init(struct drm_minor *minor)
> > -{
> > - struct drm_device *dev = minor->dev;
> > - struct panfrost_device *pfdev = platform_get_drvdata(to_platform_device(dev->dev));
> > -
> > - debugfs_create_atomic_t("profile", 0600, minor->debugfs_root, &pfdev->profile_mode);
> > -}
> > diff --git a/drivers/gpu/drm/panfrost/panfrost_debugfs.h b/drivers/gpu/drm/panfrost/panfrost_debugfs.h
> > deleted file mode 100644
> > index c5af5f35877f..000000000000
> > --- a/drivers/gpu/drm/panfrost/panfrost_debugfs.h
> > +++ /dev/null
> > @@ -1,14 +0,0 @@
> > -/* SPDX-License-Identifier: GPL-2.0 */
> > -/*
> > - * Copyright 2023 Collabora ltd.
> > - * Copyright 2023 Amazon.com, Inc. or its affiliates.
> > - */
> > -
> > -#ifndef PANFROST_DEBUGFS_H
> > -#define PANFROST_DEBUGFS_H
> > -
> > -#ifdef CONFIG_DEBUG_FS
> > -void panfrost_debugfs_init(struct drm_minor *minor);
> > -#endif
> > -
> > -#endif /* PANFROST_DEBUGFS_H */
> > diff --git a/drivers/gpu/drm/panfrost/panfrost_device.h b/drivers/gpu/drm/panfrost/panfrost_device.h
> > index 62f7e3527385..56c8e5551335 100644
> > --- a/drivers/gpu/drm/panfrost/panfrost_device.h
> > +++ b/drivers/gpu/drm/panfrost/panfrost_device.h
> > @@ -130,7 +130,10 @@ struct panfrost_device {
> > struct list_head scheduled_jobs;
> >
> > struct panfrost_perfcnt *perfcnt;
> > - atomic_t profile_mode;
> > + struct kobj_profiling {
> > + struct kobject base;
> > + atomic_t profile_mode;
> > + } profiling;
> >
> > struct mutex sched_lock;
> >
> > diff --git a/drivers/gpu/drm/panfrost/panfrost_drv.c b/drivers/gpu/drm/panfrost/panfrost_drv.c
> > index a926d71e8131..6db1ea453514 100644
> > --- a/drivers/gpu/drm/panfrost/panfrost_drv.c
> > +++ b/drivers/gpu/drm/panfrost/panfrost_drv.c
> > @@ -20,7 +20,7 @@
> > #include "panfrost_job.h"
> > #include "panfrost_gpu.h"
> > #include "panfrost_perfcnt.h"
> > -#include "panfrost_debugfs.h"
> > +#include "panfrost_sysfs.h"
> >
> > static bool unstable_ioctls;
> > module_param_unsafe(unstable_ioctls, bool, 0600);
> > @@ -600,10 +600,6 @@ static const struct drm_driver panfrost_drm_driver = {
> >
> > .gem_create_object = panfrost_gem_create_object,
> > .gem_prime_import_sg_table = panfrost_gem_prime_import_sg_table,
> > -
> > -#ifdef CONFIG_DEBUG_FS
> > - .debugfs_init = panfrost_debugfs_init,
> > -#endif
> > };
> >
> > static int panfrost_probe(struct platform_device *pdev)
> > @@ -663,8 +659,14 @@ static int panfrost_probe(struct platform_device *pdev)
> > if (err)
> > goto err_out2;
> >
> > + err = panfrost_sysfs_init(pfdev);
> > + if (err)
> > + goto err_out3;
> > +
> > return 0;
> >
> > +err_out3:
> > + panfrost_gem_shrinker_cleanup(ddev);
> > err_out2:
> > drm_dev_unregister(ddev);
> > err_out1:
> > @@ -681,6 +683,8 @@ static void panfrost_remove(struct platform_device *pdev)
> > struct panfrost_device *pfdev = platform_get_drvdata(pdev);
> > struct drm_device *ddev = pfdev->ddev;
> >
> > + panfrost_sysfs_cleanup(pfdev);
> > +
> > drm_dev_unregister(ddev);
> > panfrost_gem_shrinker_cleanup(ddev);
> >
> > diff --git a/drivers/gpu/drm/panfrost/panfrost_job.c b/drivers/gpu/drm/panfrost/panfrost_job.c
> > index 0c2dbf6ef2a5..49413dfda2ea 100644
> > --- a/drivers/gpu/drm/panfrost/panfrost_job.c
> > +++ b/drivers/gpu/drm/panfrost/panfrost_job.c
> > @@ -243,7 +243,7 @@ static void panfrost_job_hw_submit(struct panfrost_job *job, int js)
> > subslot = panfrost_enqueue_job(pfdev, js, job);
> > /* Don't queue the job if a reset is in progress */
> > if (!atomic_read(&pfdev->reset.pending)) {
> > - if (atomic_read(&pfdev->profile_mode)) {
> > + if (atomic_read(&pfdev->profiling.profile_mode)) {
> > panfrost_cycle_counter_get(pfdev);
> > job->is_profiled = true;
> > job->start_time = ktime_get();
> > diff --git a/drivers/gpu/drm/panfrost/panfrost_sysfs.c b/drivers/gpu/drm/panfrost/panfrost_sysfs.c
> > new file mode 100644
> > index 000000000000..072d3bf349d2
> > --- /dev/null
> > +++ b/drivers/gpu/drm/panfrost/panfrost_sysfs.c
> > @@ -0,0 +1,74 @@
> > +// SPDX-License-Identifier: GPL-2.0
> > +/* Copyright 2023 Collabora ltd. */
> > +/* Copyright 2023 Amazon.com, Inc. or its affiliates. */
> > +
> > +#include <linux/platform_device.h>
> > +#include <drm/drm_file.h>
> > +#include <drm/panfrost_drm.h>
> > +
> > +#include "panfrost_device.h"
> > +#include "panfrost_gpu.h"
> > +#include "panfrost_sysfs.h"
> > +
> > +static ssize_t
> > +profiling_show(struct kobject *kobj, struct kobj_attribute *attr, char *buf)
> > +{
> > + atomic_t *profile_mode =
> > + &container_of(kobj, struct {
> > + struct kobject base;
> > + atomic_t profile_mode; },
> > + base)->profile_mode;
> > +
> > + return sysfs_emit(buf, "%d\n", atomic_read(profile_mode));
> > +}
> > +
> > +static ssize_t
> > +profiling_store(struct kobject *kobj, struct kobj_attribute *attr,
> > + const char *buf, size_t count)
> > +{
> > + atomic_t *profile_mode =
> > + &container_of(kobj, struct {
> > + struct kobject base;
> > + atomic_t profile_mode; },
> > + base)->profile_mode;
> > + int err, value;
>
> Can't we just make this a RW module_param to simplify things? I fail to
> see why we need an atomic here since active cycle-count users are
> already tracked with an atomic_t that's incremented/decremented
> everytime a job is submitted/considered done.
I thought about this, and it would greatly simplify this patch to the point that
I could get rid of all the sysfs cruft, but then I remembered about someone at
Collabora once told me of a very specific customer SoC configuration with two
Mali GPU devices. I know this might be very unusual, but I guess they could be
interested in profiling a single GPU at a time, as unplausible as it sounds.
Regarding the atomic variable for keeping track of the profiling status, your'e
right, it's an overkill. I'll just get rid of it altogether in v2.
> > +
> > + err = kstrtoint(buf, 0, &value);
> > + if (err)
> > + return err;
> > +
> > + atomic_set(profile_mode, !!value);
> > +
> > + return count;
> > +}
> > +
> > +static const struct kobj_attribute profiling_status =
> > +__ATTR(status, 0644, profiling_show, profiling_store);
> > +
> > +static const struct kobj_type kobj_profile_type = {
> > + .sysfs_ops = &kobj_sysfs_ops,
> > +};
> > +
> > +int panfrost_sysfs_init(struct panfrost_device *pfdev)
> > +{
> > + struct device *kdev = pfdev->ddev->primary->kdev;
> > + int err;
> > +
> > + kobject_init(&pfdev->profiling.base, &kobj_profile_type);
> > +
> > + err = kobject_add(&pfdev->profiling.base, &kdev->kobj, "%s", "profiling");
> > + if (err)
> > + return err;
> > +
> > + err = sysfs_create_file(&pfdev->profiling.base, &profiling_status.attr);
> > + if (err)
> > + kobject_del(&pfdev->profiling.base);
> > +
> > + return err;
> > +}
> > +
> > +void panfrost_sysfs_cleanup(struct panfrost_device *pfdev)
> > +{
> > + sysfs_remove_file(&pfdev->profiling.base, &profiling_status.attr);
> > + kobject_del(&pfdev->profiling.base);
> > +}
> > diff --git a/drivers/gpu/drm/panfrost/panfrost_sysfs.h b/drivers/gpu/drm/panfrost/panfrost_sysfs.h
> > new file mode 100644
> > index 000000000000..5fc9c8c1091a
> > --- /dev/null
> > +++ b/drivers/gpu/drm/panfrost/panfrost_sysfs.h
> > @@ -0,0 +1,15 @@
> > +/* SPDX-License-Identifier: GPL-2.0 */
> > +/*
> > + * Copyright 2023 Collabora ltd.
> > + * Copyright 2023 Amazon.com, Inc. or its affiliates.
> > + */
> > +
> > +#ifndef PANFROST_SYSFS_H
> > +#define PANFROST_SYSFS_H
> > +
> > +struct panfrost_device;
> > +
> > +int panfrost_sysfs_init(struct panfrost_device *pfdev);
> > +void panfrost_sysfs_cleanup(struct panfrost_device *pfdev);
> > +
> > +#endif /* PANFROST_SYSFS_H */