LinuxLists.cc - [PATCH v2 00/20] perf/core: Generalise event exclusion checking

2018-11-26 11:15:11

Subject: [PATCH v2 00/20] perf/core: Generalise event exclusion checking

Many PMU drivers do not have the capability to exclude counting events
that occur in specific contexts such as idle, kernel, guest, etc. These
drivers indicate this by returning an error in their event_init upon
testing the events attribute flags.

However this approach requires that each time a new event modifier is
added to perf, all the perf drivers need to be modified to indicate that
they don't support the attribute. This results in additional boiler-plate
code common to many drivers that needs to be maintained. Furthermore the
drivers are not consistent with regards to the error value they return
when reporting unsupported attributes.

This patchset allow PMU drivers to advertise their ability to exclude
based on context via a new capability: PERF_PMU_CAP_EXCLUDE. This allows
the perf core to reject requests for exclusion events where there is no
support in the PMU.

This is a functional change, in particular:

- Some drivers will now additionally (but correctly) report unsupported
exclusion flags. It's typical for existing userspace tools such as
perf to handle such errors by retrying the system call without the
unsupported flags.

- Drivers that do not support any exclusion that previously reported
-EPERM or -EOPNOTSUPP will now report -EINVAL - this is consistent
with the majority and results in userspace perf retrying without
exclusion.

All drivers touched by this patchset have been compile tested.

Changes from v1:

- Changed approach from explicitly rejecting events in unsupporting PMU
drivers to explicitly advertising a capability in PMU drivers that
do support exclusion events

- Added additional information to tools/perf/design.txt

- Rename event_has_exclude_flags to event_has_any_exclude_flag and
update commit log to reflect it's a function

Andrew Murray (20):
perf/doc: update design.txt for exclude_{host|guest} flags
perf/core: add function to test for event exclusion flags
perf/core: add PERF_PMU_CAP_EXCLUDE for exclusion capable PMUs
perf/hw_breakpoint: perf/core: advertise PMU exclusion capability
alpha: perf/core: remove unnecessary checks for exclusion
arc: perf/core: advertise PMU exclusion capability
arm: perf: conditionally advertise PMU exclusion capability
arm: perf/core: remove unnecessary checks for exclusion
drivers/perf: perf/core: remove unnecessary checks for exclusion
drivers/perf: perf/core: remove unnecessary checks for exclusion
drivers/perf: perf/core: advertise PMU exclusion capability
mips: perf/core: advertise PMU exclusion capability
powerpc: perf/core: advertise PMU exclusion capability
powerpc: perf/core: remove unnecessary checks for exclusion
s390: perf/events: advertise PMU exclusion capability
sparc: perf/core: advertise PMU exclusion capability
x86: perf/core: remove unnecessary checks for exclusion
x86: perf/core remove unnecessary checks for exclusion
x86: perf/core: advertise PMU exclusion capability
perf/core: remove unused perf_flags

arch/alpha/kernel/perf_event.c | 6 ------
arch/arc/kernel/perf_event.c | 1 +
arch/arm/mach-imx/mmdc.c | 8 +-------
arch/arm/mm/cache-l2x0-pmu.c | 8 --------
arch/mips/kernel/perf_event_mipsxx.c | 1 +
arch/powerpc/perf/core-book3s.c | 1 +
arch/powerpc/perf/core-fsl-emb.c | 1 +
arch/powerpc/perf/hv-24x7.c | 9 ---------
arch/powerpc/perf/hv-gpci.c | 9 ---------
arch/powerpc/perf/imc-pmu.c | 18 ------------------
arch/s390/kernel/perf_cpum_cf.c | 1 +
arch/s390/kernel/perf_cpum_sf.c | 2 ++
arch/sparc/kernel/perf_event.c | 1 +
arch/x86/events/amd/ibs.c | 12 ------------
arch/x86/events/amd/iommu.c | 5 -----
arch/x86/events/amd/power.c | 9 +--------
arch/x86/events/amd/uncore.c | 5 -----
arch/x86/events/core.c | 2 ++
arch/x86/events/intel/bts.c | 2 +-
arch/x86/events/intel/cstate.c | 8 +-------
arch/x86/events/intel/pt.c | 4 +++-
arch/x86/events/intel/rapl.c | 8 +-------
arch/x86/events/intel/uncore.c | 8 --------
arch/x86/events/intel/uncore_snb.c | 8 +-------
arch/x86/events/msr.c | 8 +-------
drivers/perf/arm-cci.c | 9 ---------
drivers/perf/arm-ccn.c | 5 +----
drivers/perf/arm_dsu_pmu.c | 8 +-------
drivers/perf/arm_pmu.c | 15 +++++----------
drivers/perf/arm_spe_pmu.c | 3 ++-
drivers/perf/hisilicon/hisi_uncore_pmu.c | 9 ---------
drivers/perf/qcom_l2_pmu.c | 8 --------
drivers/perf/qcom_l3_pmu.c | 7 -------
drivers/perf/xgene_pmu.c | 5 -----
include/linux/perf_event.h | 10 ++++++++++
include/uapi/linux/perf_event.h | 2 --
kernel/events/core.c | 9 +++++++++
kernel/events/hw_breakpoint.c | 2 ++
tools/include/uapi/linux/perf_event.h | 2 --
tools/perf/design.txt | 4 ++++
40 files changed, 54 insertions(+), 189 deletions(-)

--
2.7.4

2018-11-26 11:15:18

by Andrew Murray

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Subject: [PATCH v2 02/20] perf/core: add function to test for event exclusion flags

Add a function that tests if any of the perf event exclusion flags
are set on a given event.

Signed-off-by: Andrew Murray <[email protected]>
---
include/linux/perf_event.h | 9 +++++++++
1 file changed, 9 insertions(+)

diff --git a/include/linux/perf_event.h b/include/linux/perf_event.h
index 53c500f..b2e806f 100644
--- a/include/linux/perf_event.h
+++ b/include/linux/perf_event.h
@@ -1004,6 +1004,15 @@ perf_event__output_id_sample(struct perf_event *event,
extern void
perf_log_lost_samples(struct perf_event *event, u64 lost);

+static inline bool event_has_any_exclude_flag(struct perf_event *event)
+{
+ struct perf_event_attr *attr = &event->attr;
+
+ return attr->exclude_idle || attr->exclude_user ||
+ attr->exclude_kernel || attr->exclude_hv ||
+ attr->exclude_guest || attr->exclude_host;
+}
+
static inline bool is_sampling_event(struct perf_event *event)
{
return event->attr.sample_period != 0;
--
2.7.4

2018-11-26 11:15:20

by Andrew Murray

[permalink] [raw]

Subject: [PATCH v2 03/20] perf/core: add PERF_PMU_CAP_EXCLUDE for exclusion capable PMUs

2018-11-26 11:15:26

by Andrew Murray

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Subject: [PATCH v2 04/20] perf/hw_breakpoint: perf/core: advertise PMU exclusion capability

The breakpoint PMU has the capability to exclude kernel contexts,
let's advertise that we support the PERF_PMU_CAP_EXCLUDE
capability so that perf doesn't prevent us from handling events
with any exclusion flags set.

Signed-off-by: Andrew Murray <[email protected]>
---
kernel/events/hw_breakpoint.c | 2 ++
1 file changed, 2 insertions(+)

diff --git a/kernel/events/hw_breakpoint.c b/kernel/events/hw_breakpoint.c
index d6b5618..fefe3d5 100644
--- a/kernel/events/hw_breakpoint.c
+++ b/kernel/events/hw_breakpoint.c
@@ -669,6 +669,8 @@ static struct pmu perf_breakpoint = {
.start = hw_breakpoint_start,
.stop = hw_breakpoint_stop,
.read = hw_breakpoint_pmu_read,
+
+ .capabilities = PERF_PMU_CAP_EXCLUDE,
};

int __init init_hw_breakpoint(void)
--
2.7.4

2018-11-26 11:15:32

by Andrew Murray

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Subject: [PATCH v2 06/20] arc: perf/core: advertise PMU exclusion capability

The ARC PMU has the capability to exclude events based on
context. Let's advertise that we support the
PERF_PMU_CAP_EXCLUDE capability to ensure that perf doesn't
prevent us from handling events where any exclusion flags are
set.

Signed-off-by: Andrew Murray <[email protected]>
---
arch/arc/kernel/perf_event.c | 1 +
1 file changed, 1 insertion(+)

diff --git a/arch/arc/kernel/perf_event.c b/arch/arc/kernel/perf_event.c
index 8aec462..cf8ea6d 100644
--- a/arch/arc/kernel/perf_event.c
+++ b/arch/arc/kernel/perf_event.c
@@ -514,6 +514,7 @@ static int arc_pmu_device_probe(struct platform_device *pdev)
.start = arc_pmu_start,
.stop = arc_pmu_stop,
.read = arc_pmu_read,
+ .capabilities = PERF_PMU_CAP_EXCLUDE,
};

if (has_interrupts) {
--
2.7.4

2018-11-26 11:15:49

by Andrew Murray

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Subject: [PATCH v2 10/20] drivers/perf: perf/core: remove unnecessary checks for exclusion

2018-11-26 11:16:00

by Andrew Murray

[permalink] [raw]

Subject: [PATCH v2 11/20] drivers/perf: perf/core: advertise PMU exclusion capability

The arm_pse PMU has the capability to exclude events based on
context. Let's advertise that we support the PERF_PMU_CAP_EXCLUDE
capability to ensure that perf doesn't prevent us from handling
events where any exclusion flags are set.

Signed-off-by: Andrew Murray <[email protected]>
---
drivers/perf/arm_spe_pmu.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/perf/arm_spe_pmu.c b/drivers/perf/arm_spe_pmu.c
index 54ec278..a09c38a 100644
--- a/drivers/perf/arm_spe_pmu.c
+++ b/drivers/perf/arm_spe_pmu.c
@@ -902,7 +902,8 @@ static int arm_spe_pmu_perf_init(struct arm_spe_pmu *spe_pmu)

spe_pmu->pmu = (struct pmu) {
.module = THIS_MODULE,
- .capabilities = PERF_PMU_CAP_EXCLUSIVE | PERF_PMU_CAP_ITRACE,
+ .capabilities = PERF_PMU_CAP_EXCLUSIVE | PERF_PMU_CAP_ITRACE |
+ PERF_PMU_CAP_EXCLUDE,
.attr_groups = arm_spe_pmu_attr_groups,
/*
* We hitch a ride on the software context here, so that
--
2.7.4

2018-11-26 11:16:06

by Andrew Murray

[permalink] [raw]

Subject: [PATCH v2 12/20] mips: perf/core: advertise PMU exclusion capability

The MIPS PMU has the capability to exclude events based on
context. Let's advertise that we support the PERF_PMU_CAP_EXCLUDE
capability to ensure that perf doesn't prevent us from handling
events where any exclusion flags are set.

Signed-off-by: Andrew Murray <[email protected]>
---
arch/mips/kernel/perf_event_mipsxx.c | 1 +
1 file changed, 1 insertion(+)

diff --git a/arch/mips/kernel/perf_event_mipsxx.c b/arch/mips/kernel/perf_event_mipsxx.c
index 4138635..d7813d0 100644
--- a/arch/mips/kernel/perf_event_mipsxx.c
+++ b/arch/mips/kernel/perf_event_mipsxx.c
@@ -670,6 +670,7 @@ static struct pmu pmu = {
.start = mipspmu_start,
.stop = mipspmu_stop,
.read = mipspmu_read,
+ .capabilities = PERF_PMU_CAP_EXCLUDE,
};

static unsigned int mipspmu_perf_event_encode(const struct mips_perf_event *pev)
--
2.7.4

2018-11-26 11:16:09

by Andrew Murray

[permalink] [raw]

Subject: [PATCH v2 13/20] powerpc: perf/core: advertise PMU exclusion capability

For PowerPC PMUs that have the capability to exclude events
based on context. Let's advertise that we support the
PERF_PMU_CAP_EXCLUDE capability to ensure that perf doesn't
prevent us from handling events where any exclusion flags are
set.

Signed-off-by: Andrew Murray <[email protected]>
---
arch/powerpc/perf/core-book3s.c | 1 +
arch/powerpc/perf/core-fsl-emb.c | 1 +
2 files changed, 2 insertions(+)

diff --git a/arch/powerpc/perf/core-book3s.c b/arch/powerpc/perf/core-book3s.c
index 81f8a0c..2f44b09 100644
--- a/arch/powerpc/perf/core-book3s.c
+++ b/arch/powerpc/perf/core-book3s.c
@@ -2007,6 +2007,7 @@ static struct pmu power_pmu = {
.commit_txn = power_pmu_commit_txn,
.event_idx = power_pmu_event_idx,
.sched_task = power_pmu_sched_task,
+ .capabilities = PERF_PMU_CAP_EXCLUDE,
};

/*
diff --git a/arch/powerpc/perf/core-fsl-emb.c b/arch/powerpc/perf/core-fsl-emb.c
index ba48584..cea5bcb 100644
--- a/arch/powerpc/perf/core-fsl-emb.c
+++ b/arch/powerpc/perf/core-fsl-emb.c
@@ -596,6 +596,7 @@ static struct pmu fsl_emb_pmu = {
.start = fsl_emb_pmu_start,
.stop = fsl_emb_pmu_stop,
.read = fsl_emb_pmu_read,
+ .capabilities = PERF_PMU_CAP_EXCLUDE,
};

/*
--
2.7.4

2018-11-26 11:16:12

by Andrew Murray

[permalink] [raw]

Subject: [PATCH v2 14/20] powerpc: perf/core: remove unnecessary checks for exclusion

For PowerPC PMUs that do not support context exclusion we do not
advertise the PERF_PMU_CAP_EXCLUDE capability. This ensures that
perf will prevent us from handling events where any exclusion
flags are set. Let's remove the now unnecessary check for exclusion
flags.

Signed-off-by: Andrew Murray <[email protected]>
---
arch/powerpc/perf/hv-24x7.c | 9 ---------
arch/powerpc/perf/hv-gpci.c | 9 ---------
arch/powerpc/perf/imc-pmu.c | 18 ------------------
3 files changed, 36 deletions(-)

diff --git a/arch/powerpc/perf/hv-24x7.c b/arch/powerpc/perf/hv-24x7.c
index 72238ee..d13d8a9 100644
--- a/arch/powerpc/perf/hv-24x7.c
+++ b/arch/powerpc/perf/hv-24x7.c
@@ -1306,15 +1306,6 @@ static int h_24x7_event_init(struct perf_event *event)
return -EINVAL;
}

- /* unsupported modes and filters */
- if (event->attr.exclude_user ||
- event->attr.exclude_kernel ||
- event->attr.exclude_hv ||
- event->attr.exclude_idle ||
- event->attr.exclude_host ||
- event->attr.exclude_guest)
- return -EINVAL;
-
/* no branch sampling */
if (has_branch_stack(event))
return -EOPNOTSUPP;
diff --git a/arch/powerpc/perf/hv-gpci.c b/arch/powerpc/perf/hv-gpci.c
index 43fabb3..e0ce0e0 100644
--- a/arch/powerpc/perf/hv-gpci.c
+++ b/arch/powerpc/perf/hv-gpci.c
@@ -232,15 +232,6 @@ static int h_gpci_event_init(struct perf_event *event)
return -EINVAL;
}

- /* unsupported modes and filters */
- if (event->attr.exclude_user ||
- event->attr.exclude_kernel ||
- event->attr.exclude_hv ||
- event->attr.exclude_idle ||
- event->attr.exclude_host ||
- event->attr.exclude_guest)
- return -EINVAL;
-
/* no branch sampling */
if (has_branch_stack(event))
return -EOPNOTSUPP;
diff --git a/arch/powerpc/perf/imc-pmu.c b/arch/powerpc/perf/imc-pmu.c
index 1fafc32b..49c0b1c 100644
--- a/arch/powerpc/perf/imc-pmu.c
+++ b/arch/powerpc/perf/imc-pmu.c
@@ -473,15 +473,6 @@ static int nest_imc_event_init(struct perf_event *event)
if (event->hw.sample_period)
return -EINVAL;

- /* unsupported modes and filters */
- if (event->attr.exclude_user ||
- event->attr.exclude_kernel ||
- event->attr.exclude_hv ||
- event->attr.exclude_idle ||
- event->attr.exclude_host ||
- event->attr.exclude_guest)
- return -EINVAL;
-
if (event->cpu < 0)
return -EINVAL;

@@ -748,15 +739,6 @@ static int core_imc_event_init(struct perf_event *event)
if (event->hw.sample_period)
return -EINVAL;

- /* unsupported modes and filters */
- if (event->attr.exclude_user ||
- event->attr.exclude_kernel ||
- event->attr.exclude_hv ||
- event->attr.exclude_idle ||
- event->attr.exclude_host ||
- event->attr.exclude_guest)
- return -EINVAL;
-
if (event->cpu < 0)
return -EINVAL;

--
2.7.4

2018-11-26 11:16:29

by Andrew Murray

[permalink] [raw]

Subject: [PATCH v2 18/20] x86: perf/core remove unnecessary checks for exclusion

For x86 PMUs that do not support context exclusion we do not
advertise the PERF_PMU_CAP_EXCLUDE capability. This ensures
that perf will prevent us from handling events where any
exclusion flags are set. Let's remove the now unnecessary
check for exclusion flags.

This change means that amd/iommu and amd/uncore will now
also indicate that they do not support exclude_{hv|idle} and
intel/uncore that it does not support exclude_{guest|host}.

Signed-off-by: Andrew Murray <[email protected]>
---
arch/x86/events/amd/iommu.c | 5 -----
arch/x86/events/amd/uncore.c | 5 -----
arch/x86/events/intel/uncore.c | 8 --------
3 files changed, 18 deletions(-)

diff --git a/arch/x86/events/amd/iommu.c b/arch/x86/events/amd/iommu.c
index 3210fee..eb35fe4 100644
--- a/arch/x86/events/amd/iommu.c
+++ b/arch/x86/events/amd/iommu.c
@@ -223,11 +223,6 @@ static int perf_iommu_event_init(struct perf_event *event)
if (is_sampling_event(event) || event->attach_state & PERF_ATTACH_TASK)
return -EINVAL;

- /* IOMMU counters do not have usr/os/guest/host bits */
- if (event->attr.exclude_user || event->attr.exclude_kernel ||
- event->attr.exclude_host || event->attr.exclude_guest)
- return -EINVAL;
-
if (event->cpu < 0)
return -EINVAL;

diff --git a/arch/x86/events/amd/uncore.c b/arch/x86/events/amd/uncore.c
index 8671de1..d6ade30 100644
--- a/arch/x86/events/amd/uncore.c
+++ b/arch/x86/events/amd/uncore.c
@@ -201,11 +201,6 @@ static int amd_uncore_event_init(struct perf_event *event)
if (is_sampling_event(event) || event->attach_state & PERF_ATTACH_TASK)
return -EINVAL;

- /* NB and Last level cache counters do not have usr/os/guest/host bits */
- if (event->attr.exclude_user || event->attr.exclude_kernel ||
- event->attr.exclude_host || event->attr.exclude_guest)
- return -EINVAL;
-
/* and we do not enable counter overflow interrupts */
hwc->config = event->attr.config & AMD64_RAW_EVENT_MASK_NB;
hwc->idx = -1;
diff --git a/arch/x86/events/intel/uncore.c b/arch/x86/events/intel/uncore.c
index 27a4614..f1d78d9 100644
--- a/arch/x86/events/intel/uncore.c
+++ b/arch/x86/events/intel/uncore.c
@@ -695,14 +695,6 @@ static int uncore_pmu_event_init(struct perf_event *event)
if (pmu->func_id < 0)
return -ENOENT;

- /*
- * Uncore PMU does measure at all privilege level all the time.
- * So it doesn't make sense to specify any exclude bits.
- */
- if (event->attr.exclude_user || event->attr.exclude_kernel ||
- event->attr.exclude_hv || event->attr.exclude_idle)
- return -EINVAL;
-
/* Sampling not supported yet */
if (hwc->sample_period)
return -EINVAL;
--
2.7.4

2018-11-26 11:16:34

by Andrew Murray

[permalink] [raw]

Subject: [PATCH v2 19/20] x86: perf/core: advertise PMU exclusion capability

For PMUs that have the capability to exclude events based
on context. Let's advertise that we support the
PERF_PMU_CAP_EXCLUDE capability to ensure that perf doesn't
prevent us from handling events where any exclusion flags
are set.

Signed-off-by: Andrew Murray <[email protected]>
---
arch/x86/events/core.c | 2 ++
arch/x86/events/intel/bts.c | 2 +-
arch/x86/events/intel/pt.c | 4 +++-
3 files changed, 6 insertions(+), 2 deletions(-)

diff --git a/arch/x86/events/core.c b/arch/x86/events/core.c
index dfb2f7c..3f51916 100644
--- a/arch/x86/events/core.c
+++ b/arch/x86/events/core.c
@@ -2297,6 +2297,8 @@ static struct pmu pmu = {
.event_idx = x86_pmu_event_idx,
.sched_task = x86_pmu_sched_task,
.task_ctx_size = sizeof(struct x86_perf_task_context),
+
+ .capabilities = PERF_PMU_CAP_EXCLUDE,
};

void arch_perf_update_userpage(struct perf_event *event,
diff --git a/arch/x86/events/intel/bts.c b/arch/x86/events/intel/bts.c
index 24ffa1e..4976695 100644
--- a/arch/x86/events/intel/bts.c
+++ b/arch/x86/events/intel/bts.c
@@ -601,7 +601,7 @@ static __init int bts_init(void)
}

bts_pmu.capabilities = PERF_PMU_CAP_AUX_NO_SG | PERF_PMU_CAP_ITRACE |
- PERF_PMU_CAP_EXCLUSIVE;
+ PERF_PMU_CAP_EXCLUSIVE | PERF_PMU_CAP_EXCLUDE;
bts_pmu.task_ctx_nr = perf_sw_context;
bts_pmu.event_init = bts_event_init;
bts_pmu.add = bts_event_add;
diff --git a/arch/x86/events/intel/pt.c b/arch/x86/events/intel/pt.c
index 8d016ce..2d811f8 100644
--- a/arch/x86/events/intel/pt.c
+++ b/arch/x86/events/intel/pt.c
@@ -1516,7 +1516,9 @@ static __init int pt_init(void)
pt_pmu.pmu.capabilities =
PERF_PMU_CAP_AUX_NO_SG | PERF_PMU_CAP_AUX_SW_DOUBLEBUF;

- pt_pmu.pmu.capabilities |= PERF_PMU_CAP_EXCLUSIVE | PERF_PMU_CAP_ITRACE;
+ pt_pmu.pmu.capabilities = PERF_PMU_CAP_EXCLUSIVE |
+ PERF_PMU_CAP_ITRACE |
+ PERF_PMU_CAP_EXCLUDE;
pt_pmu.pmu.attr_groups = pt_attr_groups;
pt_pmu.pmu.task_ctx_nr = perf_sw_context;
pt_pmu.pmu.event_init = pt_event_init;
--
2.7.4

2018-11-26 11:16:36

by Andrew Murray

[permalink] [raw]

Subject: [PATCH v2 20/20] perf/core: remove unused perf_flags

Now that perf_flags is not used we remove it.

Signed-off-by: Andrew Murray <[email protected]>
---
include/uapi/linux/perf_event.h | 2 --
tools/include/uapi/linux/perf_event.h | 2 --
2 files changed, 4 deletions(-)

diff --git a/include/uapi/linux/perf_event.h b/include/uapi/linux/perf_event.h
index f35eb72..ba89bd3 100644
--- a/include/uapi/linux/perf_event.h
+++ b/include/uapi/linux/perf_event.h
@@ -445,8 +445,6 @@ struct perf_event_query_bpf {
__u32 ids[0];
};

-#define perf_flags(attr) (*(&(attr)->read_format + 1))
-
/*
* Ioctls that can be done on a perf event fd:
*/
diff --git a/tools/include/uapi/linux/perf_event.h b/tools/include/uapi/linux/perf_event.h
index f35eb72..ba89bd3 100644
--- a/tools/include/uapi/linux/perf_event.h
+++ b/tools/include/uapi/linux/perf_event.h
@@ -445,8 +445,6 @@ struct perf_event_query_bpf {
__u32 ids[0];
};

-#define perf_flags(attr) (*(&(attr)->read_format + 1))
-
/*
* Ioctls that can be done on a perf event fd:
*/
--
2.7.4

2018-11-26 11:16:40

by Andrew Murray

[permalink] [raw]

Subject: [PATCH v2 05/20] alpha: perf/core: remove unnecessary checks for exclusion

As the Alpha PMU doesn't support context exclusion we do not
advertise the PERF_PMU_CAP_EXCLUDE capability. This ensures that
perf will prevent us from handling events where any exclusion
flags are set. Let's remove the now unnecessary check for
exclusion flags.

This change means that __hw_perf_event_init will now also
indicate that it doesn't support exclude_host and exclude_guest and
will now implicitly return -EINVAL instead of -EPERM. This is likely
more desirable as -EPERM will result in a kernel.perf_event_paranoid
related warning from the perf userspace utility.

Signed-off-by: Andrew Murray <[email protected]>
---
arch/alpha/kernel/perf_event.c | 6 ------
1 file changed, 6 deletions(-)

diff --git a/arch/alpha/kernel/perf_event.c b/arch/alpha/kernel/perf_event.c
index 5613aa37..5c17077 100644
--- a/arch/alpha/kernel/perf_event.c
+++ b/arch/alpha/kernel/perf_event.c
@@ -630,12 +630,6 @@ static int __hw_perf_event_init(struct perf_event *event)
return ev;
}

- /* The EV67 does not support mode exclusion */
- if (attr->exclude_kernel || attr->exclude_user
- || attr->exclude_hv || attr->exclude_idle) {
- return -EPERM;
- }
-
/*
* We place the event type in event_base here and leave calculation
* of the codes to programme the PMU for alpha_pmu_enable() because
--
2.7.4

2018-11-26 11:16:51

by Andrew Murray

[permalink] [raw]

Subject: [PATCH v2 07/20] arm: perf: conditionally advertise PMU exclusion capability

The ARM PMU driver can be used to represent a variety of ARM based
PMUs. Some of these PMUs provide support for context exclusion, where
this is the case we advertise this via the PERF_PMU_CAP_EXCLUDE
capability to ensure that perf doesn't prevent us from handling events
where any exclusion flags are set.

Signed-off-by: Andrew Murray <[email protected]>
---
drivers/perf/arm_pmu.c | 15 +++++----------
1 file changed, 5 insertions(+), 10 deletions(-)

diff --git a/drivers/perf/arm_pmu.c b/drivers/perf/arm_pmu.c
index 7f01f6f..4409035 100644
--- a/drivers/perf/arm_pmu.c
+++ b/drivers/perf/arm_pmu.c
@@ -357,13 +357,6 @@ static irqreturn_t armpmu_dispatch_irq(int irq, void *dev)
}

static int
-event_requires_mode_exclusion(struct perf_event_attr *attr)
-{
- return attr->exclude_idle || attr->exclude_user ||
- attr->exclude_kernel || attr->exclude_hv;
-}
-
-static int
__hw_perf_event_init(struct perf_event *event)
{
struct arm_pmu *armpmu = to_arm_pmu(event->pmu);
@@ -393,9 +386,8 @@ __hw_perf_event_init(struct perf_event *event)
/*
* Check whether we need to exclude the counter from certain modes.
*/
- if ((!armpmu->set_event_filter ||
- armpmu->set_event_filter(hwc, &event->attr)) &&
- event_requires_mode_exclusion(&event->attr)) {
+ if (armpmu->set_event_filter &&
+ armpmu->set_event_filter(hwc, &event->attr)) {
pr_debug("ARM performance counters do not support "
"mode exclusion\n");
return -EOPNOTSUPP;
@@ -861,6 +853,9 @@ int armpmu_register(struct arm_pmu *pmu)
if (ret)
return ret;

+ if (pmu->set_event_filter)
+ pmu->pmu.capabilities |= PERF_PMU_CAP_EXCLUDE;
+
ret = perf_pmu_register(&pmu->pmu, pmu->name, -1);
if (ret)
goto out_destroy;
--
2.7.4

2018-11-26 11:16:53

by Andrew Murray

[permalink] [raw]

Subject: [PATCH v2 08/20] arm: perf/core: remove unnecessary checks for exclusion

2018-11-26 11:16:56

by Andrew Murray

[permalink] [raw]

Subject: [PATCH v2 09/20] drivers/perf: perf/core: remove unnecessary checks for exclusion

2018-11-26 11:17:30

by Andrew Murray

[permalink] [raw]

Subject: [PATCH v2 16/20] sparc: perf/core: advertise PMU exclusion capability

The SPARC PMU has the capability to exclude events based on context
- let's advertise that we support the PERF_PMU_CAP_EXCLUDE
capability to ensure that perf doesn't prevent us from handling
events where any exclusion flags are set.

Signed-off-by: Andrew Murray <[email protected]>
---
arch/sparc/kernel/perf_event.c | 1 +
1 file changed, 1 insertion(+)

diff --git a/arch/sparc/kernel/perf_event.c b/arch/sparc/kernel/perf_event.c
index d3149ba..38fac17 100644
--- a/arch/sparc/kernel/perf_event.c
+++ b/arch/sparc/kernel/perf_event.c
@@ -1571,6 +1571,7 @@ static struct pmu pmu = {
.start_txn = sparc_pmu_start_txn,
.cancel_txn = sparc_pmu_cancel_txn,
.commit_txn = sparc_pmu_commit_txn,
+ .capabilities = PERF_PMU_CAP_EXCLUDE,
};

void perf_event_print_debug(void)
--
2.7.4

2018-11-26 11:17:30

by Andrew Murray

[permalink] [raw]

Subject: [PATCH v2 15/20] s390: perf/events: advertise PMU exclusion capability

The s390 cpum_cf and cpum_sf PMUs have the capability to exclude
events based on context. Let's advertise that we support the
PERF_PMU_CAP_EXCLUDE capability to ensure that perf doesn't
prevent us from handling events where any exclusion flags are set.

Signed-off-by: Andrew Murray <[email protected]>
---
arch/s390/kernel/perf_cpum_cf.c | 1 +
arch/s390/kernel/perf_cpum_sf.c | 2 ++
2 files changed, 3 insertions(+)

diff --git a/arch/s390/kernel/perf_cpum_cf.c b/arch/s390/kernel/perf_cpum_cf.c
index cc085e2..7b583ed 100644
--- a/arch/s390/kernel/perf_cpum_cf.c
+++ b/arch/s390/kernel/perf_cpum_cf.c
@@ -667,6 +667,7 @@ static struct pmu cpumf_pmu = {
.start_txn = cpumf_pmu_start_txn,
.commit_txn = cpumf_pmu_commit_txn,
.cancel_txn = cpumf_pmu_cancel_txn,
+ .capabilities = PERF_PMU_CAP_EXCLUDE,
};

static int cpumf_pmf_setup(unsigned int cpu, int flags)
diff --git a/arch/s390/kernel/perf_cpum_sf.c b/arch/s390/kernel/perf_cpum_sf.c
index 5c53e97..25a64aa 100644
--- a/arch/s390/kernel/perf_cpum_sf.c
+++ b/arch/s390/kernel/perf_cpum_sf.c
@@ -1885,6 +1885,8 @@ static struct pmu cpumf_sampling = {

.setup_aux = aux_buffer_setup,
.free_aux = aux_buffer_free,
+
+ .capabilities = PERF_PMU_CAP_EXCLUDE,
};

static void cpumf_measurement_alert(struct ext_code ext_code,
--
2.7.4

2018-11-26 11:17:33

by Andrew Murray

[permalink] [raw]

Subject: [PATCH v2 17/20] x86: perf/core: remove unnecessary checks for exclusion

For drivers that do not support context exclusion we do not
advertise the PERF_PMU_CAP_EXCLUDE capability. This ensures
that perf will prevent us from handling events where any exclusion
flags are set. Let's remove the now unnecessary check for
exclusion flags.

Signed-off-by: Andrew Murray <[email protected]>
---
arch/x86/events/amd/ibs.c | 12 ------------
arch/x86/events/amd/power.c | 9 +--------
arch/x86/events/intel/cstate.c | 8 +-------
arch/x86/events/intel/rapl.c | 8 +-------
arch/x86/events/intel/uncore_snb.c | 8 +-------
arch/x86/events/msr.c | 8 +-------
6 files changed, 5 insertions(+), 48 deletions(-)

diff --git a/arch/x86/events/amd/ibs.c b/arch/x86/events/amd/ibs.c
index d50bb4d..9e43ef6 100644
--- a/arch/x86/events/amd/ibs.c
+++ b/arch/x86/events/amd/ibs.c
@@ -253,15 +253,6 @@ static int perf_ibs_precise_event(struct perf_event *event, u64 *config)
return -EOPNOTSUPP;
}

-static const struct perf_event_attr ibs_notsupp = {
- .exclude_user = 1,
- .exclude_kernel = 1,
- .exclude_hv = 1,
- .exclude_idle = 1,
- .exclude_host = 1,
- .exclude_guest = 1,
-};
-
static int perf_ibs_init(struct perf_event *event)
{
struct hw_perf_event *hwc = &event->hw;
@@ -282,9 +273,6 @@ static int perf_ibs_init(struct perf_event *event)
if (event->pmu != &perf_ibs->pmu)
return -ENOENT;

- if (perf_flags(&event->attr) & perf_flags(&ibs_notsupp))
- return -EINVAL;
-
if (config & ~perf_ibs->config_mask)
return -EINVAL;

diff --git a/arch/x86/events/amd/power.c b/arch/x86/events/amd/power.c
index 2aefacf..ef80c60 100644
--- a/arch/x86/events/amd/power.c
+++ b/arch/x86/events/amd/power.c
@@ -136,14 +136,7 @@ static int pmu_event_init(struct perf_event *event)
return -ENOENT;

/* Unsupported modes and filters. */
- if (event->attr.exclude_user ||
- event->attr.exclude_kernel ||
- event->attr.exclude_hv ||
- event->attr.exclude_idle ||
- event->attr.exclude_host ||
- event->attr.exclude_guest ||
- /* no sampling */
- event->attr.sample_period)
+ if (event->attr.sample_period)
return -EINVAL;

if (cfg != AMD_POWER_EVENTSEL_PKG)
diff --git a/arch/x86/events/intel/cstate.c b/arch/x86/events/intel/cstate.c
index 9f8084f..af919c4 100644
--- a/arch/x86/events/intel/cstate.c
+++ b/arch/x86/events/intel/cstate.c
@@ -280,13 +280,7 @@ static int cstate_pmu_event_init(struct perf_event *event)
return -ENOENT;

/* unsupported modes and filters */
- if (event->attr.exclude_user ||
- event->attr.exclude_kernel ||
- event->attr.exclude_hv ||
- event->attr.exclude_idle ||
- event->attr.exclude_host ||
- event->attr.exclude_guest ||
- event->attr.sample_period) /* no sampling */
+ if (event->attr.sample_period) /* no sampling */
return -EINVAL;

if (event->cpu < 0)
diff --git a/arch/x86/events/intel/rapl.c b/arch/x86/events/intel/rapl.c
index 32f3e94..9cb94e6 100644
--- a/arch/x86/events/intel/rapl.c
+++ b/arch/x86/events/intel/rapl.c
@@ -397,13 +397,7 @@ static int rapl_pmu_event_init(struct perf_event *event)
return -EINVAL;

/* unsupported modes and filters */
- if (event->attr.exclude_user ||
- event->attr.exclude_kernel ||
- event->attr.exclude_hv ||
- event->attr.exclude_idle ||
- event->attr.exclude_host ||
- event->attr.exclude_guest ||
- event->attr.sample_period) /* no sampling */
+ if (event->attr.sample_period) /* no sampling */
return -EINVAL;

/* must be done before validate_group */
diff --git a/arch/x86/events/intel/uncore_snb.c b/arch/x86/events/intel/uncore_snb.c
index 8527c3e..26441eb 100644
--- a/arch/x86/events/intel/uncore_snb.c
+++ b/arch/x86/events/intel/uncore_snb.c
@@ -374,13 +374,7 @@ static int snb_uncore_imc_event_init(struct perf_event *event)
return -EINVAL;

/* unsupported modes and filters */
- if (event->attr.exclude_user ||
- event->attr.exclude_kernel ||
- event->attr.exclude_hv ||
- event->attr.exclude_idle ||
- event->attr.exclude_host ||
- event->attr.exclude_guest ||
- event->attr.sample_period) /* no sampling */
+ if (event->attr.sample_period) /* no sampling */
return -EINVAL;

/*
diff --git a/arch/x86/events/msr.c b/arch/x86/events/msr.c
index b4771a6..c4fa5d4 100644
--- a/arch/x86/events/msr.c
+++ b/arch/x86/events/msr.c
@@ -160,13 +160,7 @@ static int msr_event_init(struct perf_event *event)
return -ENOENT;

/* unsupported modes and filters */
- if (event->attr.exclude_user ||
- event->attr.exclude_kernel ||
- event->attr.exclude_hv ||
- event->attr.exclude_idle ||
- event->attr.exclude_host ||
- event->attr.exclude_guest ||
- event->attr.sample_period) /* no sampling */
+ if (event->attr.sample_period) /* no sampling */
return -EINVAL;

if (cfg >= PERF_MSR_EVENT_MAX)
--
2.7.4

2018-11-26 11:49:30

by Andrew Murray

[permalink] [raw]

Subject: [PATCH v2 01/20] perf/doc: update design.txt for exclude_{host|guest} flags

Update design.txt to reflect the presence of the exclude_host
and exclude_guest perf flags.

Signed-off-by: Andrew Murray <[email protected]>
---
tools/perf/design.txt | 4 ++++
1 file changed, 4 insertions(+)

diff --git a/tools/perf/design.txt b/tools/perf/design.txt
index a28dca2..5b2b23b 100644
--- a/tools/perf/design.txt
+++ b/tools/perf/design.txt
@@ -222,6 +222,10 @@ The 'exclude_user', 'exclude_kernel' and 'exclude_hv' bits provide a
way to request that counting of events be restricted to times when the
CPU is in user, kernel and/or hypervisor mode.

+Furthermore the 'exclude_host' and 'exclude_guest' bits provide a way
+to request counting of events restricted to guest and host contexts when
+using KVM virtualisation.
+
The 'mmap' and 'munmap' bits allow recording of PROT_EXEC mmap/munmap
operations, these can be used to relate userspace IP addresses to actual
code, even after the mapping (or even the whole process) is gone,
--
2.7.4

2018-11-26 14:14:20

by Robin Murphy

[permalink] [raw]

Subject: Re: [PATCH v2 03/20] perf/core: add PERF_PMU_CAP_EXCLUDE for exclusion capable PMUs

Hi Andrew,

On 26/11/2018 11:12, Andrew Murray wrote:
> Many PMU drivers do not have the capability to exclude counting events
> that occur in specific contexts such as idle, kernel, guest, etc. These
> drivers indicate this by returning an error in their event_init upon
> testing the events attribute flags. This approach is error prone and
> often inconsistent.
>
> Let's instead allow PMU drivers to advertise their ability to exclude
> based on context via a new capability: PERF_PMU_CAP_EXCLUDE. This
> allows the perf core to reject requests for exclusion events where
> there is no support in the PMU.
>
> Signed-off-by: Andrew Murray <[email protected]>
> ---
> include/linux/perf_event.h | 1 +
> kernel/events/core.c | 9 +++++++++
> 2 files changed, 10 insertions(+)
>
> diff --git a/include/linux/perf_event.h b/include/linux/perf_event.h
> index b2e806f..69b3d65 100644
> --- a/include/linux/perf_event.h
> +++ b/include/linux/perf_event.h
> @@ -244,6 +244,7 @@ struct perf_event;
> #define PERF_PMU_CAP_EXCLUSIVE 0x10
> #define PERF_PMU_CAP_ITRACE 0x20
> #define PERF_PMU_CAP_HETEROGENEOUS_CPUS 0x40
> +#define PERF_PMU_CAP_EXCLUDE 0x80
>
> /**
> * struct pmu - generic performance monitoring unit
> diff --git a/kernel/events/core.c b/kernel/events/core.c
> index 5a97f34..9afb33c 100644
> --- a/kernel/events/core.c
> +++ b/kernel/events/core.c
> @@ -9743,6 +9743,15 @@ static int perf_try_init_event(struct pmu *pmu, struct perf_event *event)
> if (ctx)
> perf_event_ctx_unlock(event->group_leader, ctx);
>
> + if (!ret) {
> + if (!(pmu->capabilities & PERF_PMU_CAP_EXCLUDE) &&
> + event_has_any_exclude_flag(event)) {

Technically this is a bisection-breaker, since no driver has this
capability yet - ideally, this patch should come after all the ones
introducing it to the relevant drivers (with the removal of the
now-redundant code from the other drivers at the end).

Alternatively, since we already have several other negative
capabilities, unless there's a strong feeling against adding any more
then it might work out simpler to flip it to PERF_PMU_CAP_NO_EXCLUDE,
such that we only need to introduce the core check then directly replace
the open-coded event checks with the capability in the appropriate
drivers, and need not touch the exclusion-supporting ones at all.

Robin.

> + if (event->destroy)
> + event->destroy(event);
> + ret = -EINVAL;
> + }
> + }
> +
> if (ret)
> module_put(pmu->module);
>
>

2018-11-26 14:56:48

by Andrew Murray

[permalink] [raw]

Subject: Re: [PATCH v2 03/20] perf/core: add PERF_PMU_CAP_EXCLUDE for exclusion capable PMUs

On Mon, Nov 26, 2018 at 02:10:24PM +0000, Robin Murphy wrote:
> Hi Andrew,
>
> On 26/11/2018 11:12, Andrew Murray wrote:
> > Many PMU drivers do not have the capability to exclude counting events
> > that occur in specific contexts such as idle, kernel, guest, etc. These
> > drivers indicate this by returning an error in their event_init upon
> > testing the events attribute flags. This approach is error prone and
> > often inconsistent.
> >
> > Let's instead allow PMU drivers to advertise their ability to exclude
> > based on context via a new capability: PERF_PMU_CAP_EXCLUDE. This
> > allows the perf core to reject requests for exclusion events where
> > there is no support in the PMU.
> >
> > Signed-off-by: Andrew Murray <[email protected]>
> > ---
> > include/linux/perf_event.h | 1 +
> > kernel/events/core.c | 9 +++++++++
> > 2 files changed, 10 insertions(+)
> >
> > diff --git a/include/linux/perf_event.h b/include/linux/perf_event.h
> > index b2e806f..69b3d65 100644
> > --- a/include/linux/perf_event.h
> > +++ b/include/linux/perf_event.h
> > @@ -244,6 +244,7 @@ struct perf_event;
> > #define PERF_PMU_CAP_EXCLUSIVE 0x10
> > #define PERF_PMU_CAP_ITRACE 0x20
> > #define PERF_PMU_CAP_HETEROGENEOUS_CPUS 0x40
> > +#define PERF_PMU_CAP_EXCLUDE 0x80
> > /**
> > * struct pmu - generic performance monitoring unit
> > diff --git a/kernel/events/core.c b/kernel/events/core.c
> > index 5a97f34..9afb33c 100644
> > --- a/kernel/events/core.c
> > +++ b/kernel/events/core.c
> > @@ -9743,6 +9743,15 @@ static int perf_try_init_event(struct pmu *pmu, struct perf_event *event)
> > if (ctx)
> > perf_event_ctx_unlock(event->group_leader, ctx);
> > + if (!ret) {
> > + if (!(pmu->capabilities & PERF_PMU_CAP_EXCLUDE) &&
> > + event_has_any_exclude_flag(event)) {
>
> Technically this is a bisection-breaker, since no driver has this capability
> yet - ideally, this patch should come after all the ones introducing it to
> the relevant drivers (with the removal of the now-redundant code from the
> other drivers at the end).

Indeed. Thought it is possible to first introduce the capability, update the
relevant drivers to advertise it, then add the change to core.c and finally
remove the unnecessary error checks as a result of using the new capability.
This approach could be bisection-proof.

>
> Alternatively, since we already have several other negative capabilities,
> unless there's a strong feeling against adding any more then it might work
> out simpler to flip it to PERF_PMU_CAP_NO_EXCLUDE, such that we only need to
> introduce the core check then directly replace the open-coded event checks
> with the capability in the appropriate drivers, and need not touch the
> exclusion-supporting ones at all.

This would certaintly be less risky and invasive (e.g. compare the number of
files touched between this v2 and the previous v1).

I'm happy with either approach.

Thanks,

Andrew Murray

>
> Robin.
>
> > + if (event->destroy)
> > + event->destroy(event);
> > + ret = -EINVAL;
> > + }
> > + }
> > +
> > if (ret)
> > module_put(pmu->module);
> >

2018-11-26 18:12:41

by David Miller

[permalink] [raw]

Subject: Re: [PATCH v2 16/20] sparc: perf/core: advertise PMU exclusion capability

From: Andrew Murray <[email protected]>
Date: Mon, 26 Nov 2018 11:12:32 +0000

> The SPARC PMU has the capability to exclude events based on context
> - let's advertise that we support the PERF_PMU_CAP_EXCLUDE
> capability to ensure that perf doesn't prevent us from handling
> events where any exclusion flags are set.
>
> Signed-off-by: Andrew Murray <[email protected]>

Acked-by: David S. Miller <[email protected]>

2018-11-26 18:25:44

by Suzuki K Poulose

[permalink] [raw]

Subject: Re: [PATCH v2 01/20] perf/doc: update design.txt for exclude_{host|guest} flags

Hi Andrew,

On 26/11/2018 11:12, Andrew Murray wrote:
> Update design.txt to reflect the presence of the exclude_host
> and exclude_guest perf flags.
>
> Signed-off-by: Andrew Murray <[email protected]>

Thanks a lot for adding this !

> ---
> tools/perf/design.txt | 4 ++++
> 1 file changed, 4 insertions(+)
>
> diff --git a/tools/perf/design.txt b/tools/perf/design.txt
> index a28dca2..5b2b23b 100644
> --- a/tools/perf/design.txt
> +++ b/tools/perf/design.txt
> @@ -222,6 +222,10 @@ The 'exclude_user', 'exclude_kernel' and 'exclude_hv' bits provide a
> way to request that counting of events be restricted to times when the
> CPU is in user, kernel and/or hypervisor mode.
>
> +Furthermore the 'exclude_host' and 'exclude_guest' bits provide a way
> +to request counting of events restricted to guest and host contexts when
> +using KVM virtualisation.

minor nit: could we generalise this to :

"using Linux as the hypervisor".

Otherwise, looks good to me.

Cheers
Suzuki

2018-11-27 08:25:12

by Hendrik Brueckner

[permalink] [raw]

Subject: Re: [PATCH v2 15/20] s390: perf/events: advertise PMU exclusion capability

On Mon, Nov 26, 2018 at 11:12:31AM +0000, Andrew Murray wrote:
> The s390 cpum_cf and cpum_sf PMUs have the capability to exclude
> events based on context. Let's advertise that we support the
> PERF_PMU_CAP_EXCLUDE capability to ensure that perf doesn't
> prevent us from handling events where any exclusion flags are set.
>
> Signed-off-by: Andrew Murray <[email protected]>
> ---
> arch/s390/kernel/perf_cpum_cf.c | 1 +
> arch/s390/kernel/perf_cpum_sf.c | 2 ++
> 2 files changed, 3 insertions(+)

Reviewed-by: Hendrik Brueckner <[email protected]>