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4d60e83dfc
This test checks if the output of perf stat to match event names and
metrics. So it wants the output lines to have both event name and
metric. Otherwise it should skip the line.
On AMD machines, the instruction event has two metrics and they are printed
in separate lines. It makes the line without event name like below:
# perf stat -a sleep 1
Performance counter stats for 'system wide':
64,383.34 msec cpu-clock # 64.048 CPUs utilized
14,526 context-switches # 225.617 /sec
112 cpu-migrations # 1.740 /sec
190 page-faults # 2.951 /sec
807,558,652 cycles # 0.013 GHz (83.30%)
69,809,799 stalled-cycles-frontend # 8.64% frontend cycles idle (83.30%)
196,983,266 stalled-cycles-backend # 24.39% backend cycles idle (83.30%)
424,876,008 instructions # 0.53 insn per cycle
(here) ---> # 0.46 stalled cycles per insn (83.30%)
97,788,321 branches # 1.519 M/sec (83.34%)
4,147,377 branch-misses # 4.24% of all branches (83.46%)
1.005241409 seconds time elapsed
Also modern Intel machines have TopDown metrics which also don't have
event names.
# perf stat -a sleep 1
Performance counter stats for 'system wide':
8,015.39 msec cpu-clock # 7.996 CPUs utilized
5,823 context-switches # 726.477 /sec
189 cpu-migrations # 23.580 /sec
139 page-faults # 17.342 /sec
435,139,308 cycles # 0.054 GHz
193,891,345 instructions # 0.45 insn per cycle
42,773,028 branches # 5.336 M/sec
2,298,113 branch-misses # 5.37% of all branches
TopdownL1 # 25.5 % tma_backend_bound
/--> # 7.9 % tma_bad_speculation
(here) --+ # 55.7 % tma_frontend_bound
\--> # 10.9 % tma_retiring
1.002395924 seconds time elapsed
There is a check to skip TopdownL1 and TopdownL2 specifically but it
does not cover every affected lines.
So there is another check to skip the line if it has nothing on the left
side of # sign. Well.. it seems ok but that's not enough too.
When aggregation mode (like --per-socket or --per-thread) is used, it
adds some prefix (e.g. CPU socket, task name and PID) in the output
line. So the test code ignores them to normalize result.
A problem can happen for per-thread mode when task name contains one or
more spaces. It'd only ignore the first part of the task name, and it
thinks there's something more in the line so it would not skip.
# perf stat -a --perf-thread sleep 1
...
perf-21276 # 70.2 % tma_backend_bound
perf-21276 # 3.9 % tma_bad_speculation
perf-21276 # 10.5 % tma_frontend_bound
perf-21276 # 15.3 % tma_retiring
^^^^^^^^^^
(ignored)
my task-21328 # 70.2 % tma_backend_bound
my task-21328 # 3.9 % tma_bad_speculation
my task-21328 # 10.5 % tma_frontend_bound
my task-21328 # 15.3 % tma_retiring
^^
(ignored)
So I think it should look at the metric names instead. Add skip_metric
to hold the list of names to skip. It would contain 'stalled cycles per
insn' and metrics started by 'tma_'.
Fixes:
|
||
|---|---|---|
| arch | ||
| block | ||
| certs | ||
| crypto | ||
| Documentation | ||
| drivers | ||
| fs | ||
| include | ||
| init | ||
| io_uring | ||
| ipc | ||
| kernel | ||
| lib | ||
| LICENSES | ||
| mm | ||
| net | ||
| rust | ||
| samples | ||
| scripts | ||
| security | ||
| sound | ||
| tools | ||
| usr | ||
| virt | ||
| .clang-format | ||
| .cocciconfig | ||
| .get_maintainer.ignore | ||
| .gitattributes | ||
| .gitignore | ||
| .mailmap | ||
| .rustfmt.toml | ||
| COPYING | ||
| CREDITS | ||
| Kbuild | ||
| Kconfig | ||
| MAINTAINERS | ||
| Makefile | ||
| README | ||
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.