The intention of commit 96e74ebf8d59 ("sched/debug: Add task uclamp
values to SCHED_DEBUG procfs") was to print requested and effective
task uclamp values. The requested values printed are read from p->uclamp,
which holds the last effective values. Fix this by printing the values
from p->uclamp_req.
Fixes: 96e74ebf8d59 ("sched/debug: Add task uclamp values to SCHED_DEBUG procfs")
Signed-off-by: Pavankumar Kondeti <[email protected]>
---
kernel/sched/debug.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/kernel/sched/debug.c b/kernel/sched/debug.c
index a562df5..239970b 100644
--- a/kernel/sched/debug.c
+++ b/kernel/sched/debug.c
@@ -948,8 +948,8 @@ void proc_sched_show_task(struct task_struct *p, struct pid_namespace *ns,
P(se.avg.util_est.enqueued);
#endif
#ifdef CONFIG_UCLAMP_TASK
- __PS("uclamp.min", p->uclamp[UCLAMP_MIN].value);
- __PS("uclamp.max", p->uclamp[UCLAMP_MAX].value);
+ __PS("uclamp.min", p->uclamp_req[UCLAMP_MIN].value);
+ __PS("uclamp.max", p->uclamp_req[UCLAMP_MAX].value);
__PS("effective uclamp.min", uclamp_eff_value(p, UCLAMP_MIN));
__PS("effective uclamp.max", uclamp_eff_value(p, UCLAMP_MAX));
#endif
--
Qualcomm India Private Limited, on behalf of Qualcomm Innovation Center, Inc.
Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, a Linux Foundation Collaborative Project.
On 10/05/20 13:56, Pavankumar Kondeti wrote:
> The intention of commit 96e74ebf8d59 ("sched/debug: Add task uclamp
> values to SCHED_DEBUG procfs") was to print requested and effective
> task uclamp values. The requested values printed are read from p->uclamp,
> which holds the last effective values. Fix this by printing the values
> from p->uclamp_req.
>
> Fixes: 96e74ebf8d59 ("sched/debug: Add task uclamp values to SCHED_DEBUG procfs")
> Signed-off-by: Pavankumar Kondeti <[email protected]>
Argh, Qais pointed this out to me ~ a week ago, and I left this in my todo
stack. I goofed up, sorry!
As Pavan points out, p->uclamp[foo] is just a cache of uclamp_eff_value(p,
foo) from the last time p was enqueued and runnable - what we are
interested in is indeed comparing this with the *requested* value.
I wanted to send an example along with a patch, I guess that's the kick I
needed!
My setup is a busy loop, its per-task clamps are set to (256, 768) via
sched_setattr(), and it's shoved in a cpu cgroup with uclamp settings of
(50%, 50%)
On the current master (e99332e7b4cd ("gcc-10: mark more functions __init to
avoid section mismatch warnings")), this gives me:
$ uclamp-get $PID # via sched_getattr()
uclamp.min=256 uclamp.max=768
$ cat /proc/$PID/sched | grep uclamp
uclamp.min : 256
uclamp.max : 512
effective uclamp.min : 256
effective uclamp.max : 512
With Pavan's patch, I get:
$ uclamp-get $PID # via sched_getattr()
uclamp.min=256 uclamp.max=768
$ cat /proc/$PID/sched | grep uclamp
uclamp.min : 256
uclamp.max : 768
effective uclamp.min : 256
effective uclamp.max : 512
Minor print nit below, otherwise:
Tested-and-reviewed-by: Valentin Schneider <[email protected]>
Peter/Ingo, any chance this can go to sched/urgent? I know it's a debug
interface, but I'd rather have it land in a shape that makes sense. Again,
apologies for the goof.
> ---
> kernel/sched/debug.c | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/kernel/sched/debug.c b/kernel/sched/debug.c
> index a562df5..239970b 100644
> --- a/kernel/sched/debug.c
> +++ b/kernel/sched/debug.c
> @@ -948,8 +948,8 @@ void proc_sched_show_task(struct task_struct *p, struct pid_namespace *ns,
> P(se.avg.util_est.enqueued);
> #endif
> #ifdef CONFIG_UCLAMP_TASK
> - __PS("uclamp.min", p->uclamp[UCLAMP_MIN].value);
> - __PS("uclamp.max", p->uclamp[UCLAMP_MAX].value);
> + __PS("uclamp.min", p->uclamp_req[UCLAMP_MIN].value);
> + __PS("uclamp.max", p->uclamp_req[UCLAMP_MAX].value);
While we're at it, I'd prepend this with "requested".
> __PS("effective uclamp.min", uclamp_eff_value(p, UCLAMP_MIN));
> __PS("effective uclamp.max", uclamp_eff_value(p, UCLAMP_MAX));
> #endif
On Sun, May 10, 2020 at 05:16:28PM +0100, Valentin Schneider wrote:
>
> On 10/05/20 13:56, Pavankumar Kondeti wrote:
> > The intention of commit 96e74ebf8d59 ("sched/debug: Add task uclamp
> > values to SCHED_DEBUG procfs") was to print requested and effective
> > task uclamp values. The requested values printed are read from p->uclamp,
> > which holds the last effective values. Fix this by printing the values
> > from p->uclamp_req.
> >
> > Fixes: 96e74ebf8d59 ("sched/debug: Add task uclamp values to SCHED_DEBUG procfs")
> > Signed-off-by: Pavankumar Kondeti <[email protected]>
>
> Argh, Qais pointed this out to me ~ a week ago, and I left this in my todo
> stack. I goofed up, sorry!
>
> As Pavan points out, p->uclamp[foo] is just a cache of uclamp_eff_value(p,
> foo) from the last time p was enqueued and runnable - what we are
> interested in is indeed comparing this with the *requested* value.
>
> I wanted to send an example along with a patch, I guess that's the kick I
> needed!
>
>
> My setup is a busy loop, its per-task clamps are set to (256, 768) via
> sched_setattr(), and it's shoved in a cpu cgroup with uclamp settings of
> (50%, 50%)
>
> On the current master (e99332e7b4cd ("gcc-10: mark more functions __init to
> avoid section mismatch warnings")), this gives me:
>
> $ uclamp-get $PID # via sched_getattr()
> uclamp.min=256 uclamp.max=768
>
> $ cat /proc/$PID/sched | grep uclamp
> uclamp.min : 256
> uclamp.max : 512
> effective uclamp.min : 256
> effective uclamp.max : 512
>
> With Pavan's patch, I get:
>
> $ uclamp-get $PID # via sched_getattr()
> uclamp.min=256 uclamp.max=768
>
> $ cat /proc/$PID/sched | grep uclamp
> uclamp.min : 256
> uclamp.max : 768
> effective uclamp.min : 256
> effective uclamp.max : 512
>
>
> Minor print nit below, otherwise:
> Tested-and-reviewed-by: Valentin Schneider <[email protected]>
>
> Peter/Ingo, any chance this can go to sched/urgent? I know it's a debug
> interface, but I'd rather have it land in a shape that makes sense. Again,
> apologies for the goof.
>
> > ---
> > kernel/sched/debug.c | 4 ++--
> > 1 file changed, 2 insertions(+), 2 deletions(-)
> >
> > diff --git a/kernel/sched/debug.c b/kernel/sched/debug.c
> > index a562df5..239970b 100644
> > --- a/kernel/sched/debug.c
> > +++ b/kernel/sched/debug.c
> > @@ -948,8 +948,8 @@ void proc_sched_show_task(struct task_struct *p, struct pid_namespace *ns,
> > P(se.avg.util_est.enqueued);
> > #endif
> > #ifdef CONFIG_UCLAMP_TASK
> > - __PS("uclamp.min", p->uclamp[UCLAMP_MIN].value);
> > - __PS("uclamp.max", p->uclamp[UCLAMP_MAX].value);
> > + __PS("uclamp.min", p->uclamp_req[UCLAMP_MIN].value);
> > + __PS("uclamp.max", p->uclamp_req[UCLAMP_MAX].value);
>
> While we're at it, I'd prepend this with "requested".
>
> > __PS("effective uclamp.min", uclamp_eff_value(p, UCLAMP_MIN));
> > __PS("effective uclamp.max", uclamp_eff_value(p, UCLAMP_MAX));
> > #endif
Thanks Valentin for taking a look. I have added "requested" prefix and sent
the patch.
Thanks,
Pavan
--
Qualcomm India Private Limited, on behalf of Qualcomm Innovation Center, Inc.
Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, a Linux Foundation Collaborative Project.
The following commit has been merged into the sched/urgent branch of tip:
Commit-ID: ad32bb41fca67936c0c1d6d0bdd6d3e2e9c5432f
Gitweb: https://git.kernel.org/tip/ad32bb41fca67936c0c1d6d0bdd6d3e2e9c5432f
Author: Pavankumar Kondeti <[email protected]>
AuthorDate: Sun, 10 May 2020 18:26:41 +05:30
Committer: Peter Zijlstra <[email protected]>
CommitterDate: Tue, 19 May 2020 20:34:10 +02:00
sched/debug: Fix requested task uclamp values shown in procfs
The intention of commit 96e74ebf8d59 ("sched/debug: Add task uclamp
values to SCHED_DEBUG procfs") was to print requested and effective
task uclamp values. The requested values printed are read from p->uclamp,
which holds the last effective values. Fix this by printing the values
from p->uclamp_req.
Fixes: 96e74ebf8d59 ("sched/debug: Add task uclamp values to SCHED_DEBUG procfs")
Signed-off-by: Pavankumar Kondeti <[email protected]>
Signed-off-by: Peter Zijlstra (Intel) <[email protected]>
Reviewed-by: Valentin Schneider <[email protected]>
Tested-by: Valentin Schneider <[email protected]>
Link: https://lkml.kernel.org/r/[email protected]
---
kernel/sched/debug.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/kernel/sched/debug.c b/kernel/sched/debug.c
index a562df5..239970b 100644
--- a/kernel/sched/debug.c
+++ b/kernel/sched/debug.c
@@ -948,8 +948,8 @@ void proc_sched_show_task(struct task_struct *p, struct pid_namespace *ns,
P(se.avg.util_est.enqueued);
#endif
#ifdef CONFIG_UCLAMP_TASK
- __PS("uclamp.min", p->uclamp[UCLAMP_MIN].value);
- __PS("uclamp.max", p->uclamp[UCLAMP_MAX].value);
+ __PS("uclamp.min", p->uclamp_req[UCLAMP_MIN].value);
+ __PS("uclamp.max", p->uclamp_req[UCLAMP_MAX].value);
__PS("effective uclamp.min", uclamp_eff_value(p, UCLAMP_MIN));
__PS("effective uclamp.max", uclamp_eff_value(p, UCLAMP_MAX));
#endif