linux-kernel - Re: [PATCH v2 3/4] perf record: enable runtime trace compression

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Date:   Wed, 20 Feb 2019 18:06:05 +0300
From:   Alexey Budankov <alexey.budankov@...ux.intel.com>
To:     Jiri Olsa <jolsa@...hat.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 3/4] perf record: enable runtime trace compression


On 12.02.2019 16:09, Jiri Olsa wrote:
> On Mon, Feb 11, 2019 at 11:23:40PM +0300, Alexey Budankov wrote:
>>
>> Compression is implemented using simple Zstd API and employs AIO data
>> buffer as the memory to operate on. If the API call fails for some
>> reason compression falls back to memcpy().
>>
>> Data chunks are split and packed into PERF_RECORD_COMPRESSED records
>> by 64KB at max. mmap-flush option value can be used to avoid compression
>> of every single byte of data and increase compression ratio.
>>
>> Signed-off-by: Alexey Budankov <alexey.budankov@...ux.intel.com>
>> ---
>> Changes in v2:
>> - enabled trace compression for serial trace streaming
>> - moved compression/decompression code to session layer
>>
>> ---
>>  tools/perf/builtin-record.c |  67 +++++++++-----
>>  tools/perf/util/mmap.c      | 173 +++++++++++++++++++++---------------
>>  tools/perf/util/mmap.h      |  24 +++--
>>  tools/perf/util/session.c   | 106 ++++++++++++++++++++++
>>  tools/perf/util/session.h   |  13 +++
>>  5 files changed, 280 insertions(+), 103 deletions(-)
>>
>> diff --git a/tools/perf/builtin-record.c b/tools/perf/builtin-record.c
>> index 227dbbd47d3f..435ff88dfc5e 100644
>> --- a/tools/perf/builtin-record.c
>> +++ b/tools/perf/builtin-record.c
>> @@ -112,8 +112,7 @@ static bool switch_output_time(struct record *rec)
>>  	       trigger_is_ready(&switch_output_trigger);
>>  }
>>  
>> -static int record__write(struct record *rec, struct perf_mmap *map __maybe_unused,
>> -			 void *bf, size_t size)
>> +static int record__write(struct record *rec, void *bf, size_t size)
> 
> please keep the 'struct perf_mmap *map' in, I'm using it in
> the multiple file storage, where each map holds pointer to
> its data file

Yes, it will be reverted.

Thanks,
Alexey

> 
> thanks,
> jirka
>