Commit 26dd2cb0 authored Oct 08, 2009 by Frederic Weisbecker Committed by Ingo Molnar Oct 08, 2009

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>

parent 97ea1a7f

tools/perf/util/header.c

+7 −1

Original line number	Diff line number	Diff line
		@@ -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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