Thread (3 messages) flat view 3 messages, 2 authors, 2021-02-03

Re: [PATCH] powerpc/time: enable sched clock for irqtime

From: Pingfan Liu <hidden>
Date: 2020-10-22 07:11:35

I encounter a irq flood on Power9 machine, and tries a way to work
around it by https://www.spinics.net/lists/kernel/msg3705028.html

As irq time accounting is the foundation for the method, it needs to
make irq accounting take effect on powerpc platform.

On Thu, Oct 22, 2020 at 2:51 PM Pingfan Liu [off-list ref] wrote:
quoted hunk ↗ jump to hunk
When CONFIG_IRQ_TIME_ACCOUNTING and CONFIG_VIRT_CPU_ACCOUNTING_GEN, powerpc
does not enable "sched_clock_irqtime" and can not utilize irq time
accounting.

Like x86, powerpc does not use the sched_clock_register() interface. So it
needs an dedicated call to enable_sched_clock_irqtime() to enable irq time
accounting.

Signed-off-by: Pingfan Liu <redacted>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Christophe Leroy <redacted>
Cc: Nicholas Piggin <npiggin@gmail.com>
To: linuxppc-dev@lists.ozlabs.org
---
 arch/powerpc/kernel/time.c | 2 ++
 1 file changed, 2 insertions(+)
diff --git a/arch/powerpc/kernel/time.c b/arch/powerpc/kernel/time.c
index f85539e..4083b59e 100644
--- a/arch/powerpc/kernel/time.c
+++ b/arch/powerpc/kernel/time.c
@@ -53,6 +53,7 @@
 #include <linux/of_clk.h>
 #include <linux/suspend.h>
 #include <linux/sched/cputime.h>
+#include <linux/sched/clock.h>
 #include <linux/processor.h>
 #include <asm/trace.h>
@@ -1134,6 +1135,7 @@ void __init time_init(void)
        tick_setup_hrtimer_broadcast();

        of_clk_init(NULL);
+       enable_sched_clock_irqtime();
 }

 /*
--
2.7.5
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