linux-kernel - Re: [PATCH v2 4/4] perf record: implement --affinity=node|cpu option

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Date:   Tue, 1 Jan 2019 22:39:18 +0100
From:   Jiri Olsa <jolsa@...hat.com>
To:     Alexey Budankov <alexey.budankov@...ux.intel.com>
Cc:     Arnaldo Carvalho de Melo <acme@...nel.org>,
        Ingo Molnar <mingo@...hat.com>,
        Peter Zijlstra <peterz@...radead.org>,
        Namhyung Kim <namhyung@...nel.org>,
        Alexander Shishkin <alexander.shishkin@...ux.intel.com>,
        Andi Kleen <ak@...ux.intel.com>,
        linux-kernel <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v2 4/4] perf record: implement --affinity=node|cpu option

On Mon, Dec 24, 2018 at 03:28:33PM +0300, Alexey Budankov wrote:
> 
> Implement --affinity=node|cpu option for the record mode defaulting
> to system affinity mask bouncing.
> 
> Signed-off-by: Alexey Budankov <alexey.budankov@...ux.intel.com>
> ---
>  tools/perf/Documentation/perf-record.txt |  5 +++++
>  tools/perf/builtin-record.c              | 18 ++++++++++++++++++
>  2 files changed, 23 insertions(+)
> 
> diff --git a/tools/perf/Documentation/perf-record.txt b/tools/perf/Documentation/perf-record.txt
> index d232b13ea713..efb839784f32 100644
> --- a/tools/perf/Documentation/perf-record.txt
> +++ b/tools/perf/Documentation/perf-record.txt
> @@ -440,6 +440,11 @@ Use <n> control blocks in asynchronous (Posix AIO) trace writing mode (default:
>  Asynchronous mode is supported only when linking Perf tool with libc library
>  providing implementation for Posix AIO API.
>  
> +--affinity=mode::
> +Set affinity mask of trace reading thread according to the policy defined by 'mode' value:
> +  node - thread affinity mask is set to NUMA node cpu mask of the processed mmap buffer
> +  cpu  - thread affinity mask is set to cpu of the processed mmap buffer
> +
>  --all-kernel::
>  Configure all used events to run in kernel space.
>  
> diff --git a/tools/perf/builtin-record.c b/tools/perf/builtin-record.c
> index eea96794ee45..57dc3a45d16f 100644
> --- a/tools/perf/builtin-record.c
> +++ b/tools/perf/builtin-record.c
> @@ -1653,6 +1653,21 @@ static int parse_clockid(const struct option *opt, const char *str, int unset)
>  	ui__warning("unknown clockid %s, check man page\n", ostr);
>  	return -1;
>  }
> +static int record__parse_affinity(const struct option *opt, const char *str, int unset)
> +{
> +	struct record_opts *opts = (struct record_opts *)opt->value;
> +
> +	if (!unset) {
> +		if (str) {
> +			if (!strcasecmp(str, "node"))
> +				opts->affinity = PERF_AFFINITY_NODE;
> +			else if (!strcasecmp(str, "cpu"))
> +				opts->affinity = PERF_AFFINITY_CPU;
> +		}
> +	}
> +
> +	return 0;
> +}
>  
>  static int record__parse_mmap_pages(const struct option *opt,
>  				    const char *str,
> @@ -1961,6 +1976,9 @@ static struct option __record_options[] = {
>  		     &nr_cblocks_default, "n", "Use <n> control blocks in asynchronous trace writing mode (default: 1, max: 4)",
>  		     record__aio_parse),
>  #endif
> +	OPT_CALLBACK(0, "affinity", &record.opts, "node|cpu",
> +		     "Set affinity mask of trace reading thread to NUMA node cpu mask or cpu of processed mmap buffer",
> +		     record__parse_affinity),

so this makes sense only when there's --aio and LIBNUMA
in place.. we should check for those and allow this only
for these

jirka