Commit-ID: 06b2afc0b9a26e7673856a24ab57bfb307dad394 Gitweb: http://git.kernel.org/tip/06b2afc0b9a26e7673856a24ab57bfb307dad394 Author: Don Zickus <[email protected]> AuthorDate: Wed, 20 Aug 2014 23:25:11 -0400 Committer: Arnaldo Carvalho de Melo <[email protected]> CommitDate: Fri, 22 Aug 2014 13:12:13 -0300
perf machine: Fallback to MAP__FUNCTION if daddr maps are NULL As we run "perf c2c" on more applications, we noticed we're missing significant samples from a common customer's application. Looking at the /proc/<pid>/maps file for the app, we see "rwxs" and "rwxp" permissions on many of the shared memory & heap regions, and on all the thread stacks. Because those regions have the "x" bit set, perf marks them with a MAP_FUNCTION type. Hence ip_resolve_data() never finds load or store events coming from them. We fixed this by re-calling thread__find_addr_location with MAP__FUNCTION in the case where map is NULL as a last ditch effort to map the sample before giving up and dropping it. Reported-by: Joe Mario <[email protected]> Tested-by: Joe Mario <[email protected]> Signed-off-by: Don Zickus <[email protected]> Acked-by: Jiri Olsa <[email protected]> Cc: Jiri Olsa <[email protected]> Cc: Joe Mario <[email protected]> Cc: Stephane Eranian <[email protected]> Link: http://lkml.kernel.org/r/[email protected] Signed-off-by: Arnaldo Carvalho de Melo <[email protected]> --- tools/perf/util/machine.c | 10 ++++++++++ 1 file changed, 10 insertions(+) diff --git a/tools/perf/util/machine.c b/tools/perf/util/machine.c index e00daf0..b2ec38b 100644 --- a/tools/perf/util/machine.c +++ b/tools/perf/util/machine.c @@ -1314,6 +1314,16 @@ static void ip__resolve_data(struct machine *machine, struct thread *thread, thread__find_addr_location(thread, machine, m, MAP__VARIABLE, addr, &al); + if (al.map == NULL) { + /* + * some shared data regions have execute bit set which puts + * their mapping in the MAP__FUNCTION type array. + * Check there as a fallback option before dropping the sample. + */ + thread__find_addr_location(thread, machine, m, MAP__FUNCTION, addr, + &al); + } + ams->addr = addr; ams->al_addr = al.addr; ams->sym = al.sym; -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
