linux-kernel - [PATCH] Powerpc/perf: Wire up PMI throttling

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Date:   Wed, 14 Nov 2018 19:44:25 +0530
From:   Ravi Bangoria <ravi.bangoria@...ux.ibm.com>
To:     mpe@...erman.id.au, linuxppc-dev@...ts.ozlabs.org
Cc:     benh@...nel.crashing.org, paulus@...ba.org, ebiederm@...ssion.com,
        muriloo@...ux.ibm.com, christophe.leroy@....fr, npiggin@...il.com,
        leitao@...ian.org, aneesh.kumar@...ux.vnet.ibm.com,
        linux-kernel@...r.kernel.org, naveen.n.rao@...ux.vnet.ibm.com,
        Ravi Bangoria <ravi.bangoria@...ux.ibm.com>
Subject: [PATCH] Powerpc/perf: Wire up PMI throttling

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.

Signed-off-by: Ravi Bangoria <ravi.bangoria@...ux.ibm.com>
---
 arch/powerpc/kernel/traps.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/arch/powerpc/kernel/traps.c b/arch/powerpc/kernel/traps.c
index 9a86572db1ef..44f85fa22356 100644
--- a/arch/powerpc/kernel/traps.c
+++ b/arch/powerpc/kernel/traps.c
@@ -18,6 +18,7 @@
 #include <linux/errno.h>
 #include <linux/sched.h>
 #include <linux/sched/debug.h>
+#include <linux/sched/clock.h>
 #include <linux/kernel.h>
 #include <linux/mm.h>
 #include <linux/pkeys.h>
@@ -1803,9 +1804,12 @@ void vsx_unavailable_tm(struct pt_regs *regs)
 
 void performance_monitor_exception(struct pt_regs *regs)
 {
+	u64 start_clock;
 	__this_cpu_inc(irq_stat.pmu_irqs);
 
+	start_clock = sched_clock();
 	perf_irq(regs);
+	perf_sample_event_took(sched_clock() - start_clock);
 }
 
 #ifdef CONFIG_PPC_ADV_DEBUG_REGS
-- 
2.19.1