Re: [PATCH 2/4] perf_counter: provide pagefault software events

From: Ingo Molnar
Date: Tue Mar 10 2009 - 10:59:46 EST



* Peter Zijlstra <a.p.zijlstra@xxxxxxxxx> wrote:

> Index: linux-2.6/arch/powerpc/mm/fault.c
> ===================================================================
> --- linux-2.6.orig/arch/powerpc/mm/fault.c
> +++ linux-2.6/arch/powerpc/mm/fault.c
> @@ -29,6 +29,7 @@
> #include <linux/module.h>
> #include <linux/kprobes.h>
> #include <linux/kdebug.h>
> +#include <linux/perf_counter.h>
>
> #include <asm/firmware.h>
> #include <asm/page.h>
> @@ -170,6 +171,8 @@ int __kprobes do_page_fault(struct pt_re
> die("Weird page fault", regs, SIGSEGV);
> }
>
> + perf_swcount_event(PERF_COUNT_PAGE_FAULTS, 1, regs);

Wow, that's really nice - this way we can display a profile of
pagefault events in KernelTop - as if it was a real cycles or
other hw event based profile. Have you tried it out?

Ingo
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