From: Frederic Weisbecker Date: Thu, 8 Oct 2009 20:07:29 +0000 (+0200) Subject: perf tools: Provide backward compatibility with previous perf.data version X-Git-Url: http://drtracing.org/?a=commitdiff_plain;h=26dd2cb074d9dc41c9e3cddd7bf175fd0a41febc;p=deliverable%2Flinux.git 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 Cc: Peter Zijlstra Cc: Arnaldo Carvalho de Melo Cc: Mike Galbraith Cc: Paul Mackerras LKML-Reference: <1255032449-12022-1-git-send-email-fweisbec@gmail.com> Signed-off-by: Ingo Molnar --- diff --git a/tools/perf/util/header.c b/tools/perf/util/header.c index 212fade7ee74..9aae360c0f28 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);