perf report: Implement perf.data record decompression

zstd_init(, comp_level = 0) initializes decompression part of API only
hat now consists of zstd_decompress_stream() function.

The perf.data PERF_RECORD_COMPRESSED records are decompressed using
zstd_decompress_stream() function into a linked list of mmaped memory
regions of mmap_comp_len size (struct decomp).

After decompression of one COMPRESSED record its content is iterated and
fetched for usual processing. The mmaped memory regions with
decompressed events are kept in the linked list till the tool process
termination.

When dumping raw records (e.g., perf report -D --header) file offsets of
events from compressed records are printed as zero.

Committer notes:

Since now we have support for processing PERF_RECORD_COMPRESSED, we see
none, in raw form, like we saw in the previous patch commiter notes,
they were decompressed into the usual PERF_RECORD_{FORK,MMAP,COMM,etc}
records, we only see the stats for those PERF_RECORD_COMPRESSED events,
and since I used the file generated in the commiter notes for the
previous patch, there they are, 2 compressed records:

  $ perf report --header-only | grep cmdline
  # cmdline : /home/acme/bin/perf record -z2 sleep 1
  $ perf report -D | grep COMPRESS
        COMPRESSED events:          2
        COMPRESSED events:          0
  $ perf report --stdio
  # To display the perf.data header info, please use --header/--header-only options.
  #
  #
  # Total Lost Samples: 0
  #
  # Samples: 15  of event 'cycles:u'
  # Event count (approx.): 962227
  #
  # Overhead  Command  Shared Object     Symbol
  # ........  .......  ................  ...........................
  #
      46.99%  sleep    libc-2.28.so      [.] _dl_addr
      29.24%  sleep    [unknown]         [k] 0xffffffffaea00a67
      16.45%  sleep    libc-2.28.so      [.] __GI__IO_un_link.part.1
       5.92%  sleep    ld-2.28.so        [.] _dl_setup_hash
       1.40%  sleep    libc-2.28.so      [.] __nanosleep
       0.00%  sleep    [unknown]         [k] 0xffffffffaea00163

  #
  # (Tip: To see callchains in a more compact form: perf report -g folded)
  #
  $

Signed-off-by: Alexey Budankov <alexey.budankov@linux.intel.com>
Reviewed-by: Jiri Olsa <jolsa@kernel.org>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/304b0a59-942c-3fe1-da02-aa749f87108b@linux.intel.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

1 files changed, 11 insertions, 0 deletions

diff --git a/tools/perf/util/compress.h b/tools/perf/util/compress.h
index 1041a4fd81e2..0cd3369af2a4 100644
--- a/tools/perf/util/compress.h
+++ b/tools/perf/util/compress.h
@@ -20,6 +20,7 @@ bool lzma_is_compressed(const char *input);
 struct zstd_data {
 #ifdef HAVE_ZSTD_SUPPORT
 	ZSTD_CStream	*cstream;
+	ZSTD_DStream	*dstream;
 #endif
 };
 
@@ -31,6 +32,9 @@ 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));
+
+size_t zstd_decompress_stream(struct zstd_data *data, void *src, size_t src_size,
+			      void *dst, size_t dst_size);
 #else /* !HAVE_ZSTD_SUPPORT */
 
 static inline int zstd_init(struct zstd_data *data __maybe_unused, int level __maybe_unused)
@@ -52,6 +56,13 @@ size_t zstd_compress_stream_to_records(struct zstd_data *data __maybe_unused,
 {
 	return 0;
 }
+
+static inline size_t zstd_decompress_stream(struct zstd_data *data __maybe_unused, void *src __maybe_unused,
+					    size_t src_size __maybe_unused, void *dst __maybe_unused,
+					    size_t dst_size __maybe_unused)
+{
+	return 0;
+}
 #endif
 
 #endif /* PERF_COMPRESS_H */