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From: David Ahern <dsahern@gmail.com>
To: Namhyung Kim <namhyung@gmail.com>
Cc: Arnaldo Carvalho de Melo <acme@ghostprotocols.net>,
	Peter Zijlstra <a.p.zijlstra@chello.nl>,
	Paul Mackerras <paulus@samba.org>, Ingo Molnar <mingo@elte.hu>,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH 2/5] perf record: Add error message for EMFILE
Date: Sun, 29 Jan 2012 08:28:07 -0700	[thread overview]
Message-ID: <4F256587.3090504@gmail.com> (raw)
In-Reply-To: <1327827356-8786-2-git-send-email-namhyung@gmail.com>



On 01/29/2012 01:55 AM, Namhyung Kim wrote:
> When a user tries to open so many events, perf_event_oen syscall
> may fail with EMFILE. Provide an advice for that case.
> 
> Signed-off-by: Namhyung Kim <namhyung@gmail.com>
> ---
>  tools/perf/builtin-record.c |    4 ++++
>  1 files changed, 4 insertions(+), 0 deletions(-)
> 
> diff --git a/tools/perf/builtin-record.c b/tools/perf/builtin-record.c
> index 32870eef952f..5d3b6794d93b 100644
> --- a/tools/perf/builtin-record.c
> +++ b/tools/perf/builtin-record.c
> @@ -249,6 +249,10 @@ try_again:
>  				ui__warning("The %s event is not supported.\n",
>  					    event_name(pos));
>  				exit(EXIT_FAILURE);
> +			} else if (err == EMFILE) {
> +				ui__warning("Too many events are opened.\n"
> +					    "Try again after reducing the number of events.\n");
> +				exit(EXIT_FAILURE);
>  			}
>  
>  			printf("\n");

It's not just the number of events: an fd is opened for each specified
event on each specified cpu and for each specified task. See
__perf_evsel__open(). e.g., the new --uid option on a 16 cpu server can
hit the limit pretty fast.

David

  reply	other threads:[~2012-01-29 15:28 UTC|newest]

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-01-29  8:55 [PATCH 1/5] perf top: Use active evsel for non-sample events on old kernel Namhyung Kim
2012-01-29  8:55 ` [PATCH 2/5] perf record: Add error message for EMFILE Namhyung Kim
2012-01-29 15:28   ` David Ahern [this message]
2012-01-30  1:09     ` Namhyung Kim
     [not found]       ` <CAKYOsXxxmG8xQfPcn9xW+Dzd_-Qo8jUv8071UHdC18RBatq=uw@mail.gmail.com>
2012-01-30 18:56         ` Arnaldo Carvalho de Melo
2012-01-29  8:55 ` [PATCH 3/5] perf stat: " Namhyung Kim
2012-01-29  8:55 ` [PATCH 4/5] perf tools: Remove unnecessary ctype.h inclusion Namhyung Kim
2012-01-31 13:22   ` [tip:perf/core] " tip-bot for Namhyung Kim
2012-01-29  8:55 ` [PATCH 5/5] perf lock: Document lock info subcommand Namhyung Kim
2012-01-31 13:21   ` [tip:perf/core] " tip-bot for Namhyung Kim
2012-01-30 18:55 ` [PATCH 1/5] perf top: Use active evsel for non-sample events on old kernel Arnaldo Carvalho de Melo
2012-01-31  0:31   ` Namhyung Kim
2012-01-31  0:34     ` Arnaldo Carvalho de Melo

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