linux-kernel - Re: [PATCH v10 09/12] perf record: implement -z,--compression

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Date:   Tue, 14 May 2019 17:20:41 -0300
From:   Arnaldo Carvalho de Melo <arnaldo.melo@...il.com>
To:     Alexey Budankov <alexey.budankov@...ux.intel.com>
Cc:     Jiri Olsa <jolsa@...hat.com>, Namhyung Kim <namhyung@...nel.org>,
        Alexander Shishkin <alexander.shishkin@...ux.intel.com>,
        Peter Zijlstra <peterz@...radead.org>,
        Ingo Molnar <mingo@...hat.com>,
        Andi Kleen <ak@...ux.intel.com>,
        linux-kernel <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v10 09/12] perf record: implement
 -z,--compression_level[=<n>] option

Em Mon, Mar 18, 2019 at 08:44:42PM +0300, Alexey Budankov escreveu:
> 
> Implemented -z,--compression_level[=<n>] option that enables compression
> of mmaped kernel data buffers content in runtime during perf record
> mode collection. Default option value is 1 (fastest compression).
> 
> Compression overhead has been measured for serial and AIO streaming
> when profiling matrix multiplication workload:
> 
>     -------------------------------------------------------------
>     | SERIAL			  | AIO-1                       |
> ----------------------------------------------------------------|
> |-z | OVH(x) | ratio(x) size(MiB) | OVH(x) | ratio(x) size(MiB) |
> |---------------------------------------------------------------|
> | 0 | 1,00   | 1,000    179,424   | 1,00   | 1,000    187,527   |
> | 1 | 1,04   | 8,427    181,148   | 1,01   | 8,474    188,562   |
> | 2 | 1,07   | 8,055    186,953   | 1,03   | 7,912    191,773   |
> | 3 | 1,04   | 8,283    181,908   | 1,03   | 8,220    191,078   |
> | 5 | 1,09   | 8,101    187,705   | 1,05   | 7,780    190,065   |
> | 8 | 1,05   | 9,217    179,191   | 1,12   | 6,111    193,024   |
> -----------------------------------------------------------------
> 
> OVH = (Execution time with -z N) / (Execution time with -z 0)
> 
> ratio - compression ratio
> size  - number of bytes that was compressed
> 
> 	size ~= trace size x ratio

[root@...co ~]# perf record -z2
^C[ perf record: Woken up 1 times to write data ]
0x1746e0 [0x76]: failed to process type: 81 [Invalid argument]
[ perf record: Captured and wrote 1.568 MB perf.data, compressed (original 0.452 MB, ratio is 3.995) ]

[root@...co ~]#

I've pushed what I have to the tmp.perf/core branch, please try to see
if I made any mistake in fixing up conflicts with BPF_PROG_INFO and
BPF_BTF header features. I'll continue tomorrow with 10-12/12.

- Arnaldo
 
> Signed-off-by: Alexey Budankov <alexey.budankov@...ux.intel.com>
> ---
>  tools/perf/Documentation/perf-record.txt |  5 +++++
>  tools/perf/builtin-record.c              | 25 ++++++++++++++++++++++++
>  2 files changed, 30 insertions(+)
> 
> diff --git a/tools/perf/Documentation/perf-record.txt b/tools/perf/Documentation/perf-record.txt
> index 18fceb49434e..0567bacc2ae6 100644
> --- a/tools/perf/Documentation/perf-record.txt
> +++ b/tools/perf/Documentation/perf-record.txt
> @@ -471,6 +471,11 @@ Also at some cases executing less trace write syscalls with bigger data size can
>  shorter than executing more trace write syscalls with smaller data size thus lowering
>  runtime profiling overhead.
>  
> +-z::
> +--compression-level[=n]::
> +Produce compressed trace using specified level n (default: 1 - fastest compression,
> +22 - smallest trace)
> +
>  --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 2e083891affa..7258f2964a3b 100644
> --- a/tools/perf/builtin-record.c
> +++ b/tools/perf/builtin-record.c
> @@ -440,6 +440,26 @@ static int record__mmap_flush_parse(const struct option *opt,
>  	return 0;
>  }
>  
> +#ifdef HAVE_ZSTD_SUPPORT
> +static unsigned int comp_level_default = 1;
> +static int record__parse_comp_level(const struct option *opt,
> +				    const char *str,
> +				    int unset)
> +{
> +	struct record_opts *opts = (struct record_opts *)opt->value;
> +
> +	if (unset) {
> +		opts->comp_level = 0;
> +	} else {
> +		if (str)
> +			opts->comp_level = strtol(str, NULL, 0);
> +		if (!opts->comp_level)
> +			opts->comp_level = comp_level_default;
> +	}
> +
> +	return 0;
> +}
> +#endif
>  static unsigned int comp_level_max = 22;
>  
>  static int record__comp_enabled(struct record *rec)
> @@ -2169,6 +2189,11 @@ static struct option __record_options[] = {
>  	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),
> +#ifdef HAVE_ZSTD_SUPPORT
> +	OPT_CALLBACK_OPTARG('z', "compression-level", &record.opts, &comp_level_default,
> +		     "n", "Produce compressed trace using specified level (default: 1 - fastest compression, 22 - smallest trace)",
> +		     record__parse_comp_level),
> +#endif
>  	OPT_END()
>  };
>  
> -- 
> 2.20.1

-- 

- Arnaldo