Messages in this thread Patch in this message | | | Date | Thu, 8 Oct 2009 20:16:38 GMT | From | tip-bot for Frederic Weisbecker <> | Subject | [tip:perf/core] perf tools: Provide backward compatibility with previous perf.data version |
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Commit-ID: 26dd2cb074d9dc41c9e3cddd7bf175fd0a41febc Gitweb: http://git.kernel.org/tip/26dd2cb074d9dc41c9e3cddd7bf175fd0a41febc Author: Frederic Weisbecker <fweisbec@gmail.com> AuthorDate: Thu, 8 Oct 2009 22:07:29 +0200 Committer: Ingo Molnar <mingo@elte.hu> CommitDate: Thu, 8 Oct 2009 22:11:02 +0200
perf tools: Provide backward compatibility with previous perf.data version
We have merged the trace.info file into perf.data by adding one section in the perf headers. This makes it incompatible with previous version: the new perf tools can't read the older perf.data.
To support the previous format, we check the headers size. If they have the same size than in the previous format, then ignore the trace info section that doesn't exist.
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Mike Galbraith <efault@gmx.de> Cc: Paul Mackerras <paulus@samba.org> LKML-Reference: <1255032449-12022-1-git-send-email-fweisbec@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu> --- tools/perf/util/header.c | 8 +++++++- 1 files changed, 7 insertions(+), 1 deletions(-)
diff --git a/tools/perf/util/header.c b/tools/perf/util/header.c index 212fade..9aae360 100644 --- a/tools/perf/util/header.c +++ b/tools/perf/util/header.c @@ -287,10 +287,16 @@ struct perf_header *perf_header__read(int fd) do_read(fd, &f_header, sizeof(f_header)); if (f_header.magic != PERF_MAGIC || - f_header.size != sizeof(f_header) || f_header.attr_size != sizeof(f_attr)) die("incompatible file format"); + if (f_header.size != sizeof(f_header)) { + /* Support the previous format */ + if (f_header.size == offsetof(typeof(f_header), trace_info)) + f_header.trace_info.size = 0; + else + die("incompatible file format"); + } nr_attrs = f_header.attrs.size / sizeof(f_attr); lseek(fd, f_header.attrs.offset, SEEK_SET);
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