From 69996df486fc3921bbaaa17fca0d68f537f9eabf Mon Sep 17 00:00:00 2001 From: Stephane Eranian Date: Thu, 9 Feb 2012 23:21:06 +0100 Subject: perf tools: Enable reading of perf.data files from different ABI rev This patch allows perf to process perf.data files generated using an ABI that has a different perf_event_attr struct size, i.e., a different ABI version. The perf_event_attr can be extended, yet perf needs to cope with older perf.data files. Similarly, perf must be able to cope with a perf.data file which is using a newer version of the ABI than what it knows about. This patch adds read_attr(), a routine that reads a perf_event_attr struct from a file incrementally based on its advertised size. If the on-file struct is smaller than what perf knows, then the extra fields are zeroed. If the on-file struct is bigger, then perf only uses what it knows about, the rest is skipped. Signed-off-by: Stephane Eranian Cc: peterz@infradead.org Cc: acme@redhat.com Cc: robert.richter@amd.com Cc: ming.m.lin@intel.com Cc: andi@firstfloor.org Cc: asharma@fb.com Cc: ravitillo@lbl.gov Cc: vweaver1@eecs.utk.edu Cc: khandual@linux.vnet.ibm.com Cc: dsahern@gmail.com Link: http://lkml.kernel.org/r/1328826068-11713-17-git-send-email-eranian@google.com Signed-off-by: Ingo Molnar --- tools/perf/util/session.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'tools/perf/util/session.c') diff --git a/tools/perf/util/session.c b/tools/perf/util/session.c index bec8a32..e650de8 100644 --- a/tools/perf/util/session.c +++ b/tools/perf/util/session.c @@ -24,7 +24,7 @@ static int perf_session__open(struct perf_session *self, bool force) self->fd = STDIN_FILENO; if (perf_session__read_header(self, self->fd) < 0) - pr_err("incompatible file format"); + pr_err("incompatible file format (rerun with -v to learn more)"); return 0; } @@ -56,7 +56,7 @@ static int perf_session__open(struct perf_session *self, bool force) } if (perf_session__read_header(self, self->fd) < 0) { - pr_err("incompatible file format"); + pr_err("incompatible file format (rerun with -v to learn more)"); goto out_close; } -- cgit v1.1