perf stat: Show percore counts in per CPU output

We have supported the event modifier "percore" which sums up the event
counts for all hardware threads in a core and show the counts per core.

For example,

 # perf stat -e cpu/event=cpu-cycles,percore/ -a -A -- sleep 1

  Performance counter stats for 'system wide':

 S0-D0-C0                395,072      cpu/event=cpu-cycles,percore/
 S0-D0-C1                851,248      cpu/event=cpu-cycles,percore/
 S0-D0-C2                954,226      cpu/event=cpu-cycles,percore/
 S0-D0-C3              1,233,659      cpu/event=cpu-cycles,percore/

This patch provides a new option "--percore-show-thread". It is used
with event modifier "percore" together to sum up the event counts for
all hardware threads in a core but show the counts per hardware thread.

This is essentially a replacement for the any bit (which is gone in
Icelake). Per core counts are useful for some formulas, e.g. CoreIPC.
The original percore version was inconvenient to post process. This
variant matches the output of the any bit.

With this patch, for example,

 # perf stat -e cpu/event=cpu-cycles,percore/ -a -A --percore-show-thread  -- sleep 1

  Performance counter stats for 'system wide':

 CPU0               2,453,061      cpu/event=cpu-cycles,percore/
 CPU1               1,823,921      cpu/event=cpu-cycles,percore/
 CPU2               1,383,166      cpu/event=cpu-cycles,percore/
 CPU3               1,102,652      cpu/event=cpu-cycles,percore/
 CPU4               2,453,061      cpu/event=cpu-cycles,percore/
 CPU5               1,823,921      cpu/event=cpu-cycles,percore/
 CPU6               1,383,166      cpu/event=cpu-cycles,percore/
 CPU7               1,102,652      cpu/event=cpu-cycles,percore/

We can see counts are duplicated in CPU pairs (CPU0/CPU4, CPU1/CPU5,
CPU2/CPU6, CPU3/CPU7).

The interval mode also works. For example,

 # perf stat -e cpu/event=cpu-cycles,percore/ -a -A --percore-show-thread  -I 1000
 #           time CPU                    counts unit events
      1.000425421 CPU0                 925,032      cpu/event=cpu-cycles,percore/
      1.000425421 CPU1                 430,202      cpu/event=cpu-cycles,percore/
      1.000425421 CPU2                 436,843      cpu/event=cpu-cycles,percore/
      1.000425421 CPU3               1,192,504      cpu/event=cpu-cycles,percore/
      1.000425421 CPU4                 925,032      cpu/event=cpu-cycles,percore/
      1.000425421 CPU5                 430,202      cpu/event=cpu-cycles,percore/
      1.000425421 CPU6                 436,843      cpu/event=cpu-cycles,percore/
      1.000425421 CPU7               1,192,504      cpu/event=cpu-cycles,percore/

If we offline CPU5, the result is:

 # perf stat -e cpu/event=cpu-cycles,percore/ -a -A --percore-show-thread -- sleep 1

  Performance counter stats for 'system wide':

 CPU0               2,752,148      cpu/event=cpu-cycles,percore/
 CPU1               1,009,312      cpu/event=cpu-cycles,percore/
 CPU2               2,784,072      cpu/event=cpu-cycles,percore/
 CPU3               2,427,922      cpu/event=cpu-cycles,percore/
 CPU4               2,752,148      cpu/event=cpu-cycles,percore/
 CPU6               2,784,072      cpu/event=cpu-cycles,percore/
 CPU7               2,427,922      cpu/event=cpu-cycles,percore/

        1.001416041 seconds time elapsed

 v4:
 ---
 Ravi Bangoria reports an issue in v3. Once we offline a CPU,
 the output is not correct. The issue is we should use the cpu
 idx in print_percore_thread rather than using the cpu value.

 v3:
 ---
 1. Fix the interval mode output error
 2. Use cpu value (not cpu index) in config->aggr_get_id().
 3. Refine the code according to Jiri's comments.

 v2:
 ---
 Add the explanation in change log. This is essentially a replacement
 for the any bit. No code change.

Signed-off-by: Jin Yao <yao.jin@linux.intel.com>
Tested-by: Ravi Bangoria <ravi.bangoria@linux.ibm.com>
Acked-by: Jiri Olsa <jolsa@kernel.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Kan Liang <kan.liang@linux.intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lore.kernel.org/lkml/20200214080452.26402-1-yao.jin@linux.intel.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

1 files changed, 9 insertions, 0 deletions

diff --git a/tools/perf/Documentation/perf-stat.txt b/tools/perf/Documentation/perf-stat.txt
index 9431b8066fb4..4d56586b2fb9 100644
--- a/tools/perf/Documentation/perf-stat.txt
+++ b/tools/perf/Documentation/perf-stat.txt
@@ -334,6 +334,15 @@ Configure all used events to run in kernel space.
 --all-user::
 Configure all used events to run in user space.
 
+--percore-show-thread::
+The event modifier "percore" has supported to sum up the event counts
+for all hardware threads in a core and show the counts per core.
+
+This option with event modifier "percore" enabled also sums up the event
+counts for all hardware threads in a core but show the sum counts per
+hardware thread. This is essentially a replacement for the any bit and
+convenient for post processing.
+
 EXAMPLES
 --------