5f148e7c6a
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 42641d6f4d15e6db
("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>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.