The Topdown Microarchitecture Analysis (TMA) Method is a structured
analysis methodology to identify critical performance bottlenecks in
out-of-order processors.
The Topdown metrics L1 event was added as default in 42641d6f4d
("perf stat: Add Topdown metrics events as default events")
From the Sapphire Rapids server and later platforms, the same dedicated
"metrics" register is extended to support both L1 and L2 events.
Add both L1 and L2 Topdown metrics events as default to enrich the
default measuring information if the new measurement register is
available.
On legacy systems there is no change to avoid extra multiplexing.
The topdown_level indicates the max metrics level for the top-down
statistics. Set it to 2 to display all L1 and L2 Topdown metrics events.
With the patch:
$ perf stat sleep 1
Performance counter stats for 'sleep 1':
0.59 msec task-clock # 0.001 CPUs utilized
1 context-switches # 1.687 K/sec
0 cpu-migrations # 0.000 /sec
76 page-faults # 128.198 K/sec
1,405,318 cycles # 2.371 GHz
1,471,136 instructions # 1.05 insn per cycle
310,132 branches # 523.136 M/sec
10,435 branch-misses # 3.36% of all branches
8,431,908 slots # 14.223 G/sec
1,554,116 topdown-retiring # 18.4% retiring
1,289,585 topdown-bad-spec # 15.2% bad speculation
2,810,636 topdown-fe-bound # 33.2% frontend bound
2,810,636 topdown-be-bound # 33.2% backend bound
231,464 topdown-heavy-ops # 2.7% heavy operations # 15.6% light operations
1,223,453 topdown-br-mispredict # 14.5% branch mispredict # 0.8% machine clears
1,884,779 topdown-fetch-lat # 22.3% fetch latency # 10.9% fetch bandwidth
1,454,917 topdown-mem-bound # 17.2% memory bound # 16.0% Core bound
1.001179699 seconds time elapsed
0.000000000 seconds user
0.001238000 seconds sys
Signed-off-by: Kan Liang <kan.liang@linux.intel.com>
Reviewed-by: Andi Kleen <ak@linux.intel.com>
Acked-by: Namhyung Kim <namhyung@kernel.org>
Cc: Jin Yao <yao.jin@linux.intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Link: http://lore.kernel.org/lkml/1625760169-18396-1-git-send-email-kan.liang@intel.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
The Topdown Microarchitecture Analysis (TMA) Method is a structured
analysis methodology to identify critical performance bottlenecks in
out-of-order processors. From the Ice Lake and later platforms, the
Topdown information can be retrieved from the dedicated "metrics"
register, which isn't impacted by other events. Also, the Topdown
metrics support both per thread/process and per core measuring. Adding
Topdown metrics events as default events can enrich the default
measuring information, and would not cost any extra multiplexing.
Introduce arch_evlist__add_default_attrs() to allow architecture
specific default events. Add the Topdown metrics events in the X86
specific arch_evlist__add_default_attrs(). Other architectures can add
their own default events later separately.
With the patch:
$ perf stat sleep 1
Performance counter stats for 'sleep 1':
0.82 msec task-clock:u # 0.001 CPUs utilized
0 context-switches:u # 0.000 K/sec
0 cpu-migrations:u # 0.000 K/sec
61 page-faults:u # 0.074 M/sec
319,941 cycles:u # 0.388 GHz
242,802 instructions:u # 0.76 insn per cycle
54,380 branches:u # 66.028 M/sec
4,043 branch-misses:u # 7.43% of all branches
1,585,555 slots:u # 1925.189 M/sec
238,941 topdown-retiring:u # 15.0% retiring
410,378 topdown-bad-spec:u # 25.8% bad speculation
634,222 topdown-fe-bound:u # 39.9% frontend bound
304,675 topdown-be-bound:u # 19.2% backend bound
1.001791625 seconds time elapsed
0.000000000 seconds user
0.001572000 seconds sys
Signed-off-by: Kan Liang <kan.liang@linux.intel.com>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Jin Yao <yao.jin@linux.intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Link: http://lore.kernel.org/lkml/20210121133752.118327-1-kan.liang@linux.intel.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
