Re: [PATCH v5 06/10] perf util: introduce Zstd based streaming compression API

[Jiri Olsa]

On Fri, Mar 01, 2019 at 06:52:10PM +0300, Alexey Budankov wrote:
> 
> Implemented functions are based on Zstd streaming compression API. 
> The functions are used in runtime to compress data that come from 
> mmaped kernel buffer data and then stored into a trace.

please describe the usage of the api in the changelog

thanks,
jirka

> 
> Signed-off-by: Alexey Budankov <alexey.budankov@xxxxxxxxxxxxxxx>
> ---
>  tools/perf/util/Build      |  2 +
>  tools/perf/util/compress.h | 18 ++++++++
>  tools/perf/util/zstd.c     | 95 ++++++++++++++++++++++++++++++++++++++
>  3 files changed, 115 insertions(+)
>  create mode 100644 tools/perf/util/zstd.c
> 
> diff --git a/tools/perf/util/Build b/tools/perf/util/Build
> index 8dd3102301ea..920ee8bebd83 100644
> --- a/tools/perf/util/Build
> +++ b/tools/perf/util/Build
> @@ -145,6 +145,8 @@ perf-y += scripting-engines/
>  
>  perf-$(CONFIG_ZLIB) += zlib.o
>  perf-$(CONFIG_LZMA) += lzma.o
> +perf-y += zstd.o
> +
>  perf-y += demangle-java.o
>  perf-y += demangle-rust.o
>  
> diff --git a/tools/perf/util/compress.h b/tools/perf/util/compress.h
> index 892e92e7e7fc..e0987616db94 100644
> --- a/tools/perf/util/compress.h
> +++ b/tools/perf/util/compress.h
> @@ -2,6 +2,11 @@
>  #ifndef PERF_COMPRESS_H
>  #define PERF_COMPRESS_H
>  
> +#include <stdbool.h>
> +#ifdef HAVE_ZSTD_SUPPORT
> +#include <zstd.h>
> +#endif
> +
>  #ifdef HAVE_ZLIB_SUPPORT
>  int gzip_decompress_to_file(const char *input, int output_fd);
>  bool gzip_is_compressed(const char *input);
> @@ -12,4 +17,17 @@ int lzma_decompress_to_file(const char *input, int output_fd);
>  bool lzma_is_compressed(const char *input);
>  #endif
>  
> +struct zstd_data {
> +#ifdef HAVE_ZSTD_SUPPORT
> +	ZSTD_CStream	*cstream;
> +#endif
> +};
> +
> +int zstd_init(struct zstd_data *data, int level);
> +int zstd_fini(struct zstd_data *data);
> +
> +size_t zstd_compress_stream_to_records(struct zstd_data *data,
> +	void *dst, size_t dst_size, void *src, size_t src_size,	size_t max_record_size,
> +	size_t process_header(void *record, size_t increment));
> +
>  #endif /* PERF_COMPRESS_H */
> diff --git a/tools/perf/util/zstd.c b/tools/perf/util/zstd.c
> new file mode 100644
> index 000000000000..e5d44d0f6b5d
> --- /dev/null
> +++ b/tools/perf/util/zstd.c
> @@ -0,0 +1,95 @@
> +// SPDX-License-Identifier: GPL-2.0
> +
> +#include <string.h>
> +
> +#include "util/compress.h"
> +#include "util/debug.h"
> +
> +#ifdef HAVE_ZSTD_SUPPORT
> +
> +int zstd_init(struct zstd_data *data, int level)
> +{
> +	size_t ret;
> +
> +	data->cstream = ZSTD_createCStream();
> +	if (data->cstream == NULL) {
> +		pr_err("Couldn't create compression stream.\n");
> +		return -1;
> +	}
> +
> +	ret = ZSTD_initCStream(data->cstream, level);
> +	if (ZSTD_isError(ret)) {
> +		pr_err("Failed to initialize compression stream: %s\n", ZSTD_getErrorName(ret));
> +		return -1;
> +	}
> +
> +	return 0;
> +}
> +
> +int zstd_fini(struct zstd_data *data)
> +{
> +	if (data->cstream) {
> +		ZSTD_freeCStream(data->cstream);
> +		data->cstream = NULL;
> +	}
> +
> +	return 0;
> +}
> +
> +size_t zstd_compress_stream_to_records(struct zstd_data *data,
> +	void *dst, size_t dst_size, void *src, size_t src_size,	size_t max_record_size,
> +	size_t process_header(void *record, size_t increment))
> +{
> +	size_t ret, size, compressed = 0;
> +	ZSTD_inBuffer input = { src, src_size, 0 };
> +	ZSTD_outBuffer output;
> +	void *record;
> +
> +	while (input.pos < input.size) {
> +		record = dst;
> +		size = process_header(record, 0);
> +		compressed += size;
> +		dst += size;
> +		dst_size -= size;
> +		output = (ZSTD_outBuffer){ dst, (dst_size > max_record_size) ?
> +						max_record_size : dst_size, 0 };
> +		ret = ZSTD_compressStream(data->cstream, &output, &input);
> +		ZSTD_flushStream(data->cstream, &output);
> +		if (ZSTD_isError(ret)) {
> +			pr_err("failed to compress %ld bytes: %s\n",
> +				(long)src_size, ZSTD_getErrorName(ret));
> +			memcpy(dst, src, src_size);
> +			return src_size;
> +		}
> +		size = output.pos;
> +		size = process_header(record, size);
> +		compressed += size;
> +		dst += size;
> +		dst_size -= size;
> +	}
> +
> +	return compressed;
> +}
> +
> +#else /* !HAVE_ZSTD_SUPPORT */
> +
> +int zstd_init(struct zstd_data *data __maybe_unused, int level __maybe_unused)
> +{
> +	return 0;
> +}
> +
> +int zstd_fini(struct zstd_data *data __maybe_unused)
> +{
> +	return 0;
> +}
> +
> +size_t zstd_compress_stream_to_records(struct zstd_data *data __maybe_unused,
> +		void *dst __maybe_unused, size_t dst_size __maybe_unused,
> +		void *src __maybe_unused, size_t src_size __maybe_unused,
> +		size_t max_record_size __maybe_unused,
> +		size_t process_header(void *record, size_t increment) __maybe_unused)
> +{
> +	return 0;
> +}
> +
> +#endif
> -- 
> 2.20.1
>