Patch "perf stat: Skip duration_time in setup_system_wide" has been added to the 5.4-stable tree

[Sasha Levin <sashal@xxxxxxxxxx>]

This is a note to let you know that I've just added the patch titled

    perf stat: Skip duration_time in setup_system_wide

to the 5.4-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-stat-skip-duration_time-in-setup_system_wide.patch
and it can be found in the queue-5.4 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.



commit 01a42027133e240630819952113e74c3c329ff1e
Author: Jin Yao <yao.jin@xxxxxxxxxxxxxxx>
Date:   Tue Sep 22 09:50:04 2020 +0800

    perf stat: Skip duration_time in setup_system_wide
    
    [ Upstream commit 002a3d690f95804bdef6b70b26154103518e13d9 ]
    
    Some metrics (such as DRAM_BW_Use) consists of uncore events and
    duration_time. For uncore events, counter->core.system_wide is true. But
    for duration_time, counter->core.system_wide is false so
    target.system_wide is set to false.
    
    Then 'enable_on_exec' is set in perf_event_attr of uncore event.  Kernel
    will return error when trying to open the uncore event.
    
    This patch skips the duration_time in setup_system_wide then
    target.system_wide will be set to true for the evlist of uncore events +
    duration_time.
    
    Before (tested on skylake desktop):
    
      # perf stat -M DRAM_BW_Use -- sleep 1
      Error:
      The sys_perf_event_open() syscall returned with 22 (Invalid argument) for event (arb/event=0x84,umask=0x1/).
      /bin/dmesg | grep -i perf may provide additional information.
    
    After:
    
      # perf stat -M DRAM_BW_Use -- sleep 1
    
       Performance counter stats for 'system wide':
    
                    169      arb/event=0x84,umask=0x1/ #     0.00 DRAM_BW_Use
                 40,427      arb/event=0x81,umask=0x1/
          1,000,902,197 ns   duration_time
    
            1.000902197 seconds time elapsed
    
    Fixes: e3ba76deef23064f ("perf tools: Force uncore events to system wide monitoring")
    Signed-off-by: Jin Yao <yao.jin@xxxxxxxxxxxxxxx>
    Tested-by: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
    Cc: Alexander Shishkin <alexander.shishkin@xxxxxxxxxxxxxxx>
    Cc: Andi Kleen <ak@xxxxxxxxxxxxxxx>
    Cc: Jin Yao <yao.jin@xxxxxxxxx>
    Cc: Jiri Olsa <jolsa@xxxxxxxxxx>
    Cc: Kan Liang <kan.liang@xxxxxxxxxxxxxxx>
    Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
    Link: http://lore.kernel.org/lkml/20200922015004.30114-1-yao.jin@xxxxxxxxxxxxxxx
    Signed-off-by: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
    Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>

diff --git a/tools/perf/builtin-stat.c b/tools/perf/builtin-stat.c
index ac2feddc75fdd..ea183922c4ef1 100644
--- a/tools/perf/builtin-stat.c
+++ b/tools/perf/builtin-stat.c
@@ -1671,8 +1671,10 @@ static void setup_system_wide(int forks)
 		struct evsel *counter;
 
 		evlist__for_each_entry(evsel_list, counter) {
-			if (!counter->core.system_wide)
+			if (!counter->core.system_wide &&
+			    strcmp(counter->name, "duration_time")) {
 				return;
+			}
 		}
 
 		if (evsel_list->core.nr_entries)