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07dc3a6de3
bperf has a nice ability to share PMUs, but it still does not support
inherit events during fork(), resulting in some deviations in its stat
results compared with perf.
perf stat result:
$ ./perf stat -e cycles,instructions -- ./perf test -w sqrtloop
Performance counter stats for './perf test -w sqrtloop':
2,316,038,116 cycles
2,859,350,725 instructions
1.009603637 seconds time elapsed
1.004196000 seconds user
0.003950000 seconds sys
bperf stat result:
$ ./perf stat --bpf-counters -e cycles,instructions -- \
./perf test -w sqrtloop
Performance counter stats for './perf test -w sqrtloop':
18,762,093 cycles
23,487,766 instructions
1.008913769 seconds time elapsed
1.003248000 seconds user
0.004069000 seconds sys
In order to support event inheritance, two new bpf programs are added
to monitor the fork and exit of tasks respectively. When a task is
created, add it to the filter map to enable counting, and reuse the
`accum_key` of its parent task to count together with the parent task.
When a task exits, remove it from the filter map to disable counting.
After support:
$ ./perf stat --bpf-counters -e cycles,instructions -- \
./perf test -w sqrtloop
Performance counter stats for './perf test -w sqrtloop':
2,316,252,189 cycles
2,859,946,547 instructions
1.009422314 seconds time elapsed
1.003597000 seconds user
0.004270000 seconds sys
Signed-off-by: Tengda Wu <wutengda@huaweicloud.com>
Cc: song@kernel.org
Cc: bpf@vger.kernel.org
Link: https://lore.kernel.org/r/20241021110201.325617-2-wutengda@huaweicloud.com
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
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 reStructuredText 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.