linux-kernel - Re: [PATCH 07/19] perf top: Use new idle

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Date:	Thu, 8 Aug 2013 12:06:47 -0300
From:	Arnaldo Carvalho de Melo <acme@...stprotocols.net>
To:	David Ahern <dsahern@...il.com>
Cc:	linux-kernel@...r.kernel.org, mingo@...nel.org,
	Jiri Olsa <jolsa@...hat.com>,
	Namhyung Kim <namhyung@...nel.org>,
	Frederic Weisbecker <fweisbec@...il.com>,
	Peter Zijlstra <peterz@...radead.org>,
	Stephane Eranian <eranian@...gle.com>
Subject: Re: [PATCH 07/19] perf top: Use new idle_sym check

Em Wed, Aug 07, 2013 at 10:50:49PM -0400, David Ahern escreveu:
> Avoids strcmp processing each sample.

How so? This is done just when loading a DSO, when then each symbol is
checked against this list.

Tangentially, Frédéric, wasn't there a patchset from you that marks the
context of idle samples, in perf_event_header->misc, additiotally to
PERF_RECORD_MISC_KERNEL, etc? I think there were some for IRQ context as
well, right?

- Arnaldo

> Signed-off-by: David Ahern <dsahern@...il.com>
> Cc: Ingo Molnar <mingo@...nel.org>
> Cc: Jiri Olsa <jolsa@...hat.com>
> Cc: Namhyung Kim <namhyung@...nel.org>
> Cc: Frederic Weisbecker <fweisbec@...il.com>
> Cc: Peter Zijlstra <peterz@...radead.org>
> Cc: Stephane Eranian <eranian@...gle.com>
> ---
>  tools/perf/builtin-top.c |   25 ++-----------------------
>  1 file changed, 2 insertions(+), 23 deletions(-)
> 
> diff --git a/tools/perf/builtin-top.c b/tools/perf/builtin-top.c
> index 440c3b3..8eb0e3a 100644
> --- a/tools/perf/builtin-top.c
> +++ b/tools/perf/builtin-top.c
> @@ -634,26 +634,9 @@ repeat:
>  	return NULL;
>  }
>  
> -/* Tag samples to be skipped. */
> -static const char *skip_symbols[] = {
> -	"intel_idle",
> -	"default_idle",
> -	"native_safe_halt",
> -	"cpu_idle",
> -	"enter_idle",
> -	"exit_idle",
> -	"mwait_idle",
> -	"mwait_idle_with_hints",
> -	"poll_idle",
> -	"ppc64_runlatch_off",
> -	"pseries_dedicated_idle_sleep",
> -	NULL
> -};
> -
>  static int symbol_filter(struct map *map __maybe_unused, struct symbol *sym)
>  {
>  	const char *name = sym->name;
> -	int i;
>  
>  	/*
>  	 * ppc64 uses function descriptors and appends a '.' to the
> @@ -671,12 +654,8 @@ static int symbol_filter(struct map *map __maybe_unused, struct symbol *sym)
>  	    strstr(name, "_text_end"))
>  		return 1;
>  
> -	for (i = 0; skip_symbols[i]; i++) {
> -		if (!strcmp(skip_symbols[i], name)) {
> -			sym->ignore = true;
> -			break;
> -		}
> -	}
> +	if (symbol__is_idle(sym))
> +		sym->ignore = true;
>  
>  	return 0;
>  }
> -- 
> 1.7.10.1
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