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

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Date:   Tue, 12 Feb 2019 14:08:44 +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 3/4] perf record: enable runtime trace compression

On Mon, Feb 11, 2019 at 11:23:40PM +0300, Alexey Budankov wrote:

SNIP

> diff --git a/tools/perf/util/session.c b/tools/perf/util/session.c
> index 18fb9c8cbf9c..5d406eebd058 100644
> --- a/tools/perf/util/session.c
> +++ b/tools/perf/util/session.c
> @@ -29,6 +29,112 @@
>  #include "stat.h"
>  #include "arch/common.h"
>  

I think this should not be in session.c but separated in new object

> +#ifdef HAVE_ZSTD_SUPPORT
> +int perf_session__zstd_init(struct perf_session *session, int level)
> +{
> +	size_t ret;
> +
> +	session->header.env.comp_type  = PERF_COMP_NONE;
> +	session->header.env.comp_level = 0;
> +
> +	session->zstd_cstream = ZSTD_createCStream();
> +	if (session->zstd_cstream == NULL) {
> +		pr_err("Couldn't create compression stream.\n");
> +		return -1;
> +	}
> +
> +	ret = ZSTD_initCStream(session->zstd_cstream, level);
> +	if (ZSTD_isError(ret)) {
> +		pr_err("Failed to initialize compression stream: %s\n", ZSTD_getErrorName(ret));
> +		return -1;
> +	}
> +
> +	session->header.env.comp_type  = PERF_COMP_ZSTD;
> +	session->header.env.comp_level = level;
> +
> +	return 0;
> +}
> +
> +int perf_session__zstd_fini(struct perf_session *session)
> +{
> +	if (session->zstd_cstream) {
> +		ZSTD_freeCStream(session->zstd_cstream);
> +		session->zstd_cstream = NULL;
> +	}
> +
> +	return 0;
> +}
> +
> +size_t perf_session__zstd_compress(void *to,  void *dst, size_t dst_size,
> +				   void *src, size_t src_size)
> +{
> +	struct perf_session *session = to;
> +	size_t ret, size, compressed = 0;
> +	struct compressed_event *event = NULL;
> +	/* maximum size of record data size (2^16 - 1 - header) */
> +	const size_t max_data_size = (1 << 8 * sizeof(event->header.size)) -
> +				      1 - sizeof(struct compressed_event);
> +	ZSTD_inBuffer input = { src, src_size, 0 };
> +	ZSTD_outBuffer output;
> +
> +	while (input.pos < input.size) {
> +		event = dst;
> +
> +		event->header.type = PERF_RECORD_COMPRESSED;
> +		event->header.size = size = sizeof(struct compressed_event);
> +		compressed += size;
> +		dst += size;
> +		dst_size -= size;
> +
> +		output = (ZSTD_outBuffer){ dst, (dst_size > max_data_size) ?
> +						max_data_size : dst_size, 0 };
> +		ret = ZSTD_compressStream(session->zstd_cstream, &output, &input);
> +		ZSTD_flushStream(session->zstd_cstream, &output);
> +		if (ZSTD_isError(ret)) {
> +			pr_err("failed to compress %ld bytes: %s\n",
> +				(long)src_size, ZSTD_getErrorName(ret));
> +			return perf_session__zstd_copy(session, dst, dst_size, src, src_size);
> +		}
> +		size = output.pos;
> +
> +		event->header.size += size;
> +		compressed += size;
> +		dst += size;
> +		dst_size -= size;
> +	}
> +
> +	session->bytes_transferred += src_size;
> +	session->bytes_compressed  += compressed;
> +
> +	return compressed;
> +}
> +#else /* !HAVE_ZSTD_SUPPORT */
> +int perf_session__zstd_init(struct perf_session *session __maybe_unused, int level __maybe_unused)
> +{
> +	return 0;
> +}
> +
> +int perf_session__zstd_fini(struct perf_session *session __maybe_unused)
> +{
> +	return 0;
> +}
> +
> +size_t perf_session__zstd_compress(void *to __maybe_unused,
> +				void *dst __maybe_unused, size_t dst_size __maybe_unused,
> +				void *src __maybe_unused, size_t src_size __maybe_unused)
> +{
> +	return 0;
> +}
> +#endif
> +
> +size_t perf_session__zstd_copy(void *to __maybe_unused,
> +			void *dst, size_t dst_size __maybe_unused,
> +			void *src, size_t src_size)
> +{
> +	memcpy(dst, src, src_size);
> +	return src_size;
> +}
> +

SNIP