diff mbox series

[v19,03/11] perf: arm_pmuv3: Don't disable counter in armv8pmu_enable_event()

Message ID 20250202-arm-brbe-v19-v19-3-1c1300802385@kernel.org (mailing list archive)
State New
Headers show
Series arm64/perf: Enable branch stack sampling | expand

Commit Message

Rob Herring Feb. 3, 2025, 12:42 a.m. UTC
From: Mark Rutland <mark.rutland@arm.com>

Currently armv8pmu_enable_event() starts by disabling the event counter
it has been asked to enable. This should not be necessary as the counter
(and the PMU as a whole) should not be active when
armv8pmu_enable_event() is called.

Remove the redundant call to armv8pmu_disable_event_counter(). At the
same time, remove the comment immeditately above as everything it says
is obvious from the function names below.

Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Rob Herring (Arm) <robh@kernel.org>
---
 drivers/perf/arm_pmuv3.c | 5 -----
 1 file changed, 5 deletions(-)

Comments

Anshuman Khandual Feb. 3, 2025, 6:38 a.m. UTC | #1
On 2/3/25 06:12, Rob Herring (Arm) wrote:
> From: Mark Rutland <mark.rutland@arm.com>
> 
> Currently armv8pmu_enable_event() starts by disabling the event counter
> it has been asked to enable. This should not be necessary as the counter
> (and the PMU as a whole) should not be active when
> armv8pmu_enable_event() is called.
Makes sense.

> 
> Remove the redundant call to armv8pmu_disable_event_counter(). At the
> same time, remove the comment immeditately above as everything it says

s/immeditately/immediately

> is obvious from the function names below.

But should this comment drop change be folded into the next patch which
exclusively drops all obviously redundant disable/enable comments.

> 
> Signed-off-by: Mark Rutland <mark.rutland@arm.com>
> Signed-off-by: Rob Herring (Arm) <robh@kernel.org>
> ---
>  drivers/perf/arm_pmuv3.c | 5 -----
>  1 file changed, 5 deletions(-)
> 
> diff --git a/drivers/perf/arm_pmuv3.c b/drivers/perf/arm_pmuv3.c
> index 9ebc950559c0..5406b9ca591a 100644
> --- a/drivers/perf/arm_pmuv3.c
> +++ b/drivers/perf/arm_pmuv3.c
> @@ -795,11 +795,6 @@ static void armv8pmu_enable_user_access(struct arm_pmu *cpu_pmu)
>  
>  static void armv8pmu_enable_event(struct perf_event *event)
>  {
> -	/*
> -	 * Enable counter and interrupt, and set the counter to count
> -	 * the event that we're interested in.
> -	 */
> -	armv8pmu_disable_event_counter(event);
>  	armv8pmu_write_event_type(event);
>  	armv8pmu_enable_event_irq(event);
>  	armv8pmu_enable_event_counter(event);
> 

Otherwise LGTM.

Reviewed-by: Anshuman Khandual <anshuman.khandual@arm.com>
diff mbox series

Patch

diff --git a/drivers/perf/arm_pmuv3.c b/drivers/perf/arm_pmuv3.c
index 9ebc950559c0..5406b9ca591a 100644
--- a/drivers/perf/arm_pmuv3.c
+++ b/drivers/perf/arm_pmuv3.c
@@ -795,11 +795,6 @@  static void armv8pmu_enable_user_access(struct arm_pmu *cpu_pmu)
 
 static void armv8pmu_enable_event(struct perf_event *event)
 {
-	/*
-	 * Enable counter and interrupt, and set the counter to count
-	 * the event that we're interested in.
-	 */
-	armv8pmu_disable_event_counter(event);
 	armv8pmu_write_event_type(event);
 	armv8pmu_enable_event_irq(event);
 	armv8pmu_enable_event_counter(event);