This is a note to let you know that I've just added the patch titled
perf tools: Fix DSO filtering when not finding a map for a sampled address
to the 5.10-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
perf-tools-fix-dso-filtering-when-not-finding-a-map-.patch
and it can be found in the queue-5.10 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 278a06540fb98bd789470f961bf5572b5155b955
Author: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
Date: Thu Jan 28 09:52:47 2021 -0300
perf tools: Fix DSO filtering when not finding a map for a sampled address
[ 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@xxxxxxxxxxxxxxx>
Cc: Andi Kleen <ak@xxxxxxxxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxxxxx>
Cc: Jin Yao <yao.jin@xxxxxxxxxxxxxxx>
Cc: Jiri Olsa <jolsa@xxxxxxxxxx>
Cc: Kan Liang <kan.liang@xxxxxxxxx>
Cc: Namhyung Kim <namhyung@xxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Link: http://lore.kernel.org/lkml/20210128131209.GD775562@xxxxxxxxxx
Signed-off-by: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/tools/perf/util/event.c b/tools/perf/util/event.c
index 05616d4138a96..7e440fa90c938 100644
--- a/tools/perf/util/event.c
+++ b/tools/perf/util/event.c
@@ -673,6 +673,8 @@ 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) {
