linux-kernel - Re: [PATCH v7 08/12] perf record: implement compression for AIO trace streaming

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Message-ID: <20190313143714.GE6676@krava>
Date:   Wed, 13 Mar 2019 15:37:14 +0100
From:   Jiri Olsa <jolsa@...hat.com>
To:     Alexey Budankov <alexey.budankov@...ux.intel.com>
Cc:     Arnaldo Carvalho de Melo <acme@...nel.org>,
        Namhyung Kim <namhyung@...nel.org>,
        Alexander Shishkin <alexander.shishkin@...ux.intel.com>,
        Ingo Molnar <mingo@...hat.com>,
        Peter Zijlstra <peterz@...radead.org>,
        Andi Kleen <ak@...ux.intel.com>,
        linux-kernel <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v7 08/12] perf record: implement compression for AIO
 trace streaming

On Tue, Mar 12, 2019 at 08:30:13AM +0300, Alexey Budankov wrote:
> 
> Compression is implemented using the functions from zstd.c. As the memory
> to operate on the compression uses mmap->aio.data[] buffers. If Zstd
> streaming compression API fails for some reason the data to be compressed
> are just copied into the memory buffers using plain memcpy().
> 
> Compressed trace frame consists of an array of PERF_RECORD_COMPRESSED
> records. Each element of the array is not longer that PERF_SAMPLE_MAX_SIZE
> and consists of perf_event_header followed by the compressed chunk
> that is decompressed on the loading stage.
> 
> perf_mmap__aio_push() is replaced by perf_mmap__push() which is now used
> in the both serial and AIO streaming cases. perf_mmap__push() is extended 
> with positive return values to signify absence of data ready for processing.
> 
> Signed-off-by: Alexey Budankov <alexey.budankov@...ux.intel.com>
> ---
>  tools/perf/builtin-record.c | 110 ++++++++++++++++++++++++++++--------
>  tools/perf/util/mmap.c      |  76 +------------------------
>  tools/perf/util/mmap.h      |  12 ----
>  3 files changed, 87 insertions(+), 111 deletions(-)

nice stats for adding new feature ;-)

jirka