Messages in this thread Patch in this message | | | From | Arnaldo Carvalho de Melo <> | Subject | [PATCH 12/12] perf header: Use last modification time for timestamp | Date | Thu, 16 Jan 2020 10:48:14 -0300 |
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From: Michael Petlan <mpetlan@redhat.com>
Using .st_ctime clobbers the timestamp information in perf report header whenever any operation is done with the file. Even tar-ing and untar-ing the perf.data file (which preserves the file last modification timestamp) doesn't prevent that:
[Michael@Diego tmp]$ ls -l perf.data -> -rw-------. 1 Michael Michael 169888 Dec 2 15:23 perf.data
[Michael@Diego tmp]$ perf report --header-only # ======== -> # captured on : Mon Dec 2 15:23:42 2019 [...]
[Michael@Diego tmp]$ tar c perf.data | xz > perf.data.tar.xz [Michael@Diego tmp]$ mkdir aaa [Michael@Diego tmp]$ cd aaa [Michael@Diego aaa]$ xzcat ../perf.data.tar.xz | tar x [Michael@Diego aaa]$ ls -l -a total 172 drwxrwxr-x. 2 Michael Michael 23 Jan 14 11:26 . drwxrwxr-x. 6 Michael Michael 4096 Jan 14 11:26 .. -> -rw-------. 1 Michael Michael 169888 Dec 2 15:23 perf.data
[Michael@Diego aaa]$ perf report --header-only # ======== -> # captured on : Tue Jan 14 11:26:16 2020 [...]
When using .st_mtime instead, correct information is printed:
[Michael@Diego aaa]$ ~/acme/tools/perf/perf report --header-only # ======== -> # captured on : Mon Dec 2 15:23:42 2019 [...]
Signed-off-by: Michael Petlan <mpetlan@redhat.com> Acked-by: Jiri Olsa <jolsa@kernel.org> LPU-Reference: 20200114104236.31555-1-mpetlan@redhat.com Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com> --- tools/perf/util/header.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/tools/perf/util/header.c b/tools/perf/util/header.c index 93ad27830e2b..4246e7447e54 100644 --- a/tools/perf/util/header.c +++ b/tools/perf/util/header.c @@ -2922,7 +2922,7 @@ int perf_header__fprintf_info(struct perf_session *session, FILE *fp, bool full) if (ret == -1) return -1; - stctime = st.st_ctime; + stctime = st.st_mtime; fprintf(fp, "# captured on : %s", ctime(&stctime)); fprintf(fp, "# header version : %u\n", header->version); -- 2.21.1
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