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

[Alexey Budankov]

Hi,

On 02.01.2019 0:39, Jiri Olsa wrote:
> 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@xxxxxxxxxxxxxxx>
>> ---
>>  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

Serial trace streaming also benefits from that.

Thanks,
Alexey

> 
> jirka
>