From 97365e81366f5ca16a9ce66cff4dd4c5b0d9f4db Mon Sep 17 00:00:00 2001 From: Arnaldo Carvalho de Melo Date: Mon, 3 Jul 2017 17:01:41 -0300 Subject: perf evsel: Set attr.exclude_kernel when probing max attr.precise_ip We should set attr.exclude_kernel when probing for attr.precise_ip level, otherwise !CAP_SYS_ADMIN users will not default to skidless samples in capable hardware. The increase in the paranoid level in commit 0161028b7c8a ("perf/core: Change the default paranoia level to 2") broke this, fix it by excluding kernel samples when probing. Before: $ perf record usleep 1 [ perf record: Woken up 1 times to write data ] [ perf record: Captured and wrote 0.018 MB perf.data (6 samples) ] $ perf evlist -v cycles:u: sample_freq: 4000, sample_type: IP|TID|TIME|PERIOD, exclude_kernel: 1 After: $ perf record usleep 1 [ perf record: Woken up 1 times to write data ] [ perf record: Captured and wrote 0.018 MB perf.data (8 samples) ] $ perf evlist -v cycles:ppp: sample_freq: 4000, sample_type: IP|TID|TIME|PERIOD, exclude_kernel: 1, precise_ip: 3 ^^^^^^^^^^^^^ ^^^^^^^^^^^^^ ^^^^^^^^^^^^^ $ To further clarify: we always set .exclude_kernel when non !CAP_SYS_ADMIN users profile, its just on the attr.precise_ip probing that we weren't doing so, fix it. Cc: Adrian Hunter Cc: Andy Lutomirski Cc: David Ahern Cc: Jiri Olsa Cc: Namhyung Kim Cc: Wang Nan Fixes: 7f8d1ade1b19 ("perf tools: By default use the most precise "cycles" hw counter available") Link: http://lkml.kernel.org/n/tip-t2qttwhbnua62o5gt75cueml@git.kernel.org Signed-off-by: Arnaldo Carvalho de Melo --- tools/perf/util/evsel.c | 1 + 1 file changed, 1 insertion(+) (limited to 'tools') diff --git a/tools/perf/util/evsel.c b/tools/perf/util/evsel.c index cda44b0e821c..91192415f38d 100644 --- a/tools/perf/util/evsel.c +++ b/tools/perf/util/evsel.c @@ -269,6 +269,7 @@ struct perf_evsel *perf_evsel__new_cycles(void) struct perf_event_attr attr = { .type = PERF_TYPE_HARDWARE, .config = PERF_COUNT_HW_CPU_CYCLES, + .exclude_kernel = 1, }; struct perf_evsel *evsel; -- cgit v1.2.3-59-g8ed1b From 1934adf78e33fa69570a763c7ac5353212416bb0 Mon Sep 17 00:00:00 2001 From: Jiri Olsa Date: Tue, 4 Jul 2017 15:11:31 +0200 Subject: perf unwind: Do not fail due to missing unwind support We currently fail the MMAP event processing if we don't have the MMAP event's specific arch unwind support compiled in. That's wrong and can lead to unresolved mmaps in report output for 32bit binaries on 64bit server, like in this example on x86_64 server: $ cat ex.c int main(int argc, char **argv) { while (1) {} } $ gcc -o ex -m32 ex.c $ perf record ./ex ^C[ perf record: Woken up 2 times to write data ] [ perf record: Captured and wrote 0.371 MB perf.data (9322 samples) ] Before: $ perf report --stdio SNIP # Overhead Command Shared Object Symbol # ........ ....... ................ ...................... # 100.00% ex [unknown] [.] 0x00000000080483de 0.00% ex [unknown] [.] 0x00000000f76dba4f 0.00% ex [unknown] [.] 0x00000000f76e4c11 0.00% ex [unknown] [.] 0x00000000f76daa30 After: $ perf report --stdio SNIP # Overhead Command Shared Object Symbol # ........ ....... ............. ............... # 100.00% ex ex [.] main 0.00% ex ld-2.24.so [.] _dl_start 0.00% ex ld-2.24.so [.] do_lookup_x 0.00% ex ld-2.24.so [.] _start The fix is not to fail, just warn if there's not unwind support compiled in. Reported-by: Michael Lyle Signed-off-by: Jiri Olsa Tested-by: Arnaldo Carvalho de Melo Cc: David Ahern Cc: He Kuang Cc: Namhyung Kim Cc: Peter Zijlstra Link: http://lkml.kernel.org/r/20170704131131.27508-1-jolsa@kernel.org Signed-off-by: Arnaldo Carvalho de Melo --- tools/perf/util/unwind-libunwind.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'tools') diff --git a/tools/perf/util/unwind-libunwind.c b/tools/perf/util/unwind-libunwind.c index 6d542a4e0648..8aef572d0889 100644 --- a/tools/perf/util/unwind-libunwind.c +++ b/tools/perf/util/unwind-libunwind.c @@ -50,7 +50,7 @@ int unwind__prepare_access(struct thread *thread, struct map *map, if (!ops) { pr_err("unwind: target platform=%s is not supported\n", arch); - return -1; + return 0; } out_register: unwind__register_ops(thread, ops); -- cgit v1.2.3-59-g8ed1b