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| author | Don Zickus <dzickus@redhat.com> | 2014-08-20 23:25:11 -0400 |
|---|---|---|
| committer | Arnaldo Carvalho de Melo <acme@redhat.com> | 2014-08-22 13:12:13 -0300 |
| commit | 06b2afc0b9a26e7673856a24ab57bfb307dad394 (patch) | |
| tree | 14b23f0fff463329290bde8727c168b2484cecb6 /tools/perf | |
| parent | c09a7e755c025558cb882fa20a5f30da738536fa (diff) | |
| download | linux-06b2afc0b9a26e7673856a24ab57bfb307dad394.tar.gz linux-06b2afc0b9a26e7673856a24ab57bfb307dad394.tar.bz2 linux-06b2afc0b9a26e7673856a24ab57bfb307dad394.zip | |
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 <jmario@redhat.com>
Tested-by: Joe Mario <jmario@redhat.com>
Signed-off-by: Don Zickus <dzickus@redhat.com>
Acked-by: Jiri Olsa <jolsa@kernel.org>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Joe Mario <jmario@redhat.com>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lkml.kernel.org/r/1408591511-57884-1-git-send-email-dzickus@redhat.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Diffstat (limited to 'tools/perf')
| -rw-r--r-- | tools/perf/util/machine.c | 10 |
1 files changed, 10 insertions, 0 deletions
diff --git a/tools/perf/util/machine.c b/tools/perf/util/machine.c index e00daf0d2bde..b2ec38bf211e 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; |