mirror of
https://github.com/torvalds/linux.git
synced 2024-11-10 22:21:40 +00:00
A mirror of the official Linux kernel repository just in case
b03b89b350
It bothered me that during benchmarking using 'perf stat' (to collect
for example CPU cache events) I could not simultaneously retrieve the
times spend in user or kernel mode in a machine readable format.
When running 'perf stat' the output for humans contains the times
reported by rusage and wait4.
$ perf stat -e cache-misses:u -- true
Performance counter stats for 'true':
4,206 cache-misses:u
0.001113619 seconds time elapsed
0.001175000 seconds user
0.000000000 seconds sys
But 'perf stat's machine-readable format does not provide this information.
$ perf stat -x, -e cache-misses:u -- true
4282,,cache-misses:u,492859,100.00,,
I found no way to retrieve this information using the available events
while using machine-readable output.
This patch adds two new tool internal events 'user_time' and
'system_time', similarly to the already present 'duration_time' event.
Both events use the already collected rusage information obtained by
wait4 and tracked in the global ru_stats.
Examples presenting cache-misses and rusage information in both human
and machine-readable form:
$ perf stat -e duration_time,user_time,system_time,cache-misses -- grep -q -r duration_time .
Performance counter stats for 'grep -q -r duration_time .':
67,422,542 ns duration_time:u
50,517,000 ns user_time:u
16,839,000 ns system_time:u
30,937 cache-misses:u
0.067422542 seconds time elapsed
0.050517000 seconds user
0.016839000 seconds sys
$ perf stat -x, -e duration_time,user_time,system_time,cache-misses -- grep -q -r duration_time .
72134524,ns,duration_time:u,72134524,100.00,,
65225000,ns,user_time:u,65225000,100.00,,
6865000,ns,system_time:u,6865000,100.00,,
38705,,cache-misses:u,71189328,100.00,,
Signed-off-by: Florian Fischer <florian.fischer@muhq.space>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Xing Zhengjun <zhengjun.xing@linux.intel.com>
Link: https://lore.kernel.org/r/20220420102354.468173-3-florian.fischer@muhq.space
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
|
||
|---|---|---|
| arch | ||
| block | ||
| certs | ||
| crypto | ||
| Documentation | ||
| drivers | ||
| fs | ||
| include | ||
| init | ||
| ipc | ||
| kernel | ||
| lib | ||
| LICENSES | ||
| mm | ||
| net | ||
| samples | ||
| scripts | ||
| security | ||
| sound | ||
| tools | ||
| usr | ||
| virt | ||
| .clang-format | ||
| .cocciconfig | ||
| .get_maintainer.ignore | ||
| .gitattributes | ||
| .gitignore | ||
| .mailmap | ||
| 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.