From: Arnaldo Carvalho de Melo acme@redhat.com
[ Upstream commit c69bf11ad3d30b6bf01cfa538ddff1a59467c734 ]
When we lookup an address and don't find a map we should filter that sample if the user specified a list of --dso entries to filter on, fix it.
Before:
$ perf script sleep 274800 2843.556162: 1 cycles:u: ffffffffbb26bff4 [unknown] ([unknown]) sleep 274800 2843.556168: 1 cycles:u: ffffffffbb2b047d [unknown] ([unknown]) sleep 274800 2843.556171: 1 cycles:u: ffffffffbb2706b2 [unknown] ([unknown]) sleep 274800 2843.556174: 6 cycles:u: ffffffffbb2b0267 [unknown] ([unknown]) sleep 274800 2843.556176: 59 cycles:u: ffffffffbb2b03b1 [unknown] ([unknown]) sleep 274800 2843.556180: 691 cycles:u: ffffffffbb26bff4 [unknown] ([unknown]) sleep 274800 2843.556189: 9160 cycles:u: 7fa9550eeaa3 __GI___tunables_init+0xf3 (/usr/lib64/ld-2.32.so) sleep 274800 2843.556312: 86937 cycles:u: 7fa9550e157b _dl_lookup_symbol_x+0x4b (/usr/lib64/ld-2.32.so) $
So we have some samples we somehow didn't find in a map for, if we now do:
$ perf report --stdio --dso /usr/lib64/ld-2.32.so # dso: /usr/lib64/ld-2.32.so # # Total Lost Samples: 0 # # Samples: 8 of event 'cycles:u' # Event count (approx.): 96856 # # Overhead Command Symbol # ........ ....... ........................ # 89.76% sleep [.] _dl_lookup_symbol_x 9.46% sleep [.] __GI___tunables_init 0.71% sleep [k] 0xffffffffbb26bff4 0.06% sleep [k] 0xffffffffbb2b03b1 0.01% sleep [k] 0xffffffffbb2b0267 0.00% sleep [k] 0xffffffffbb2706b2 0.00% sleep [k] 0xffffffffbb2b047d $
After this patch we get the right output with just entries for the DSOs specified in --dso:
$ perf report --stdio --dso /usr/lib64/ld-2.32.so # dso: /usr/lib64/ld-2.32.so # # Total Lost Samples: 0 # # Samples: 8 of event 'cycles:u' # Event count (approx.): 96856 # # Overhead Command Symbol # ........ ....... ........................ # 89.76% sleep [.] _dl_lookup_symbol_x 9.46% sleep [.] __GI___tunables_init $ #
Fixes: 96415e4d3f5fdf9c ("perf symbols: Avoid unnecessary symbol loading when dso list is specified") Cc: Alexander Shishkin alexander.shishkin@linux.intel.com Cc: Andi Kleen ak@linux.intel.com Cc: Ingo Molnar mingo@redhat.com Cc: Jin Yao yao.jin@linux.intel.com Cc: Jiri Olsa jolsa@kernel.org Cc: Kan Liang kan.liang@intel.com Cc: Namhyung Kim namhyung@kernel.org Cc: Peter Zijlstra peterz@infradead.org Link: http://lore.kernel.org/lkml/20210128131209.GD775562@kernel.org Signed-off-by: Arnaldo Carvalho de Melo acme@redhat.com Signed-off-by: Sasha Levin sashal@kernel.org --- tools/perf/util/event.c | 2 ++ 1 file changed, 2 insertions(+)
diff --git a/tools/perf/util/event.c b/tools/perf/util/event.c index fc1e5a991008d..bfaa9afdb8b4c 100644 --- a/tools/perf/util/event.c +++ b/tools/perf/util/event.c @@ -597,6 +597,8 @@ int machine__resolve(struct machine *machine, struct addr_location *al, }
al->sym = map__find_symbol(al->map, al->addr); + } else if (symbol_conf.dso_list) { + al->filtered |= (1 << HIST_FILTER__DSO); }
if (symbol_conf.sym_list &&