* [PATCH v2] Powerpc/perf: Wire up PMI throttling
@ 2018-11-21 3:56 Ravi Bangoria
2018-12-23 13:27 ` [v2] " Michael Ellerman
0 siblings, 1 reply; 2+ messages in thread
From: Ravi Bangoria @ 2018-11-21 3:56 UTC (permalink / raw)
To: mpe, linuxppc-dev
Cc: benh, paulus, ebiederm, muriloo, christophe.leroy, npiggin,
leitao, aneesh.kumar, linux-kernel, naveen.n.rao, maddy,
Ravi Bangoria
Commit 14c63f17b1fde ("perf: Drop sample rate when sampling is too
slow") introduced a way to throttle PMU interrupts if we're spending
too much time just processing those. Wire up powerpc PMI handler to
use this infrastructure.
We have throttling of the *rate* of interrupts, but this adds
throttling based on the *time taken* to process the interrupts.
Signed-off-by: Ravi Bangoria <ravi.bangoria@linux.ibm.com>
---
v1: https://lkml.org/lkml/2018/11/14/627
arch/powerpc/perf/core-book3s.c | 11 ++++++++++-
1 file changed, 10 insertions(+), 1 deletion(-)
diff --git a/arch/powerpc/perf/core-book3s.c b/arch/powerpc/perf/core-book3s.c
index 81f8a0c838ae..3cd2ec9c9732 100644
--- a/arch/powerpc/perf/core-book3s.c
+++ b/arch/powerpc/perf/core-book3s.c
@@ -10,6 +10,7 @@
*/
#include <linux/kernel.h>
#include <linux/sched.h>
+#include <linux/sched/clock.h>
#include <linux/perf_event.h>
#include <linux/percpu.h>
#include <linux/hardirq.h>
@@ -2148,7 +2149,7 @@ static bool pmc_overflow(unsigned long val)
/*
* Performance monitor interrupt stuff
*/
-static void perf_event_interrupt(struct pt_regs *regs)
+static void __perf_event_interrupt(struct pt_regs *regs)
{
int i, j;
struct cpu_hw_events *cpuhw = this_cpu_ptr(&cpu_hw_events);
@@ -2232,6 +2233,14 @@ static void perf_event_interrupt(struct pt_regs *regs)
irq_exit();
}
+static void perf_event_interrupt(struct pt_regs *regs)
+{
+ u64 start_clock = sched_clock();
+
+ __perf_event_interrupt(regs);
+ perf_sample_event_took(sched_clock() - start_clock);
+}
+
static int power_pmu_prepare_cpu(unsigned int cpu)
{
struct cpu_hw_events *cpuhw = &per_cpu(cpu_hw_events, cpu);
--
2.17.1
^ permalink raw reply related [flat|nested] 2+ messages in thread
* Re: [v2] Powerpc/perf: Wire up PMI throttling
2018-11-21 3:56 [PATCH v2] Powerpc/perf: Wire up PMI throttling Ravi Bangoria
@ 2018-12-23 13:27 ` Michael Ellerman
0 siblings, 0 replies; 2+ messages in thread
From: Michael Ellerman @ 2018-12-23 13:27 UTC (permalink / raw)
To: Ravi Bangoria, linuxppc-dev
Cc: Ravi Bangoria, maddy, linux-kernel, npiggin, paulus, ebiederm,
muriloo, leitao, naveen.n.rao, aneesh.kumar
On Wed, 2018-11-21 at 03:56:37 UTC, Ravi Bangoria wrote:
> Commit 14c63f17b1fde ("perf: Drop sample rate when sampling is too
> slow") introduced a way to throttle PMU interrupts if we're spending
> too much time just processing those. Wire up powerpc PMI handler to
> use this infrastructure.
>
> We have throttling of the *rate* of interrupts, but this adds
> throttling based on the *time taken* to process the interrupts.
>
> Signed-off-by: Ravi Bangoria <ravi.bangoria@linux.ibm.com>
Applied to powerpc next, thanks.
https://git.kernel.org/powerpc/c/0c9108b083706330cd5484d121fbb0
cheers
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