mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
synced 2026-05-07 17:27:11 -04:00
93d10af26b
Currently when using ordered events we parse the sample twice (the
perf_evlist__parse_sample function). Once before we queue the sample for
sorting:
perf_session__process_event
perf_evlist__parse_sample(sample)
perf_session__queue_event(sample.time)
And then when we deliver the sorted sample:
ordered_events__deliver_event
perf_evlist__parse_sample
perf_session__deliver_event
We can skip the initial full sample parsing by using
perf_evlist__parse_sample_timestamp function, which got introduced
earlier. The new path looks like:
perf_session__process_event
perf_evlist__parse_sample_timestamp
perf_session__queue_event
ordered_events__deliver_event
perf_session__deliver_event
perf_evlist__parse_sample
It saves some instructions and is slightly faster:
Before:
Performance counter stats for './perf.old report --stdio' (5 runs):
64,396,007,225 cycles:u ( +- 0.97% )
105,882,112,735 instructions:u # 1.64 insn per cycle ( +- 0.00% )
21.618103465 seconds time elapsed ( +- 1.12% )
After:
Performance counter stats for './perf report --stdio' (5 runs):
60,567,807,182 cycles:u ( +- 0.40% )
104,853,333,514 instructions:u # 1.73 insn per cycle ( +- 0.00% )
20.168895243 seconds time elapsed ( +- 0.32% )
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Wang Nan <wangnan0@huawei.com>
Link: http://lkml.kernel.org/n/tip-cjp2tuk0qkjs9dxzlpmm34ua@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Linux kernel ============ This file was moved to Documentation/admin-guide/README.rst Please notice that there are several guides for kernel developers and users. These guides can be rendered in a number of formats, like HTML and PDF. In order to build the documentation, use ``make htmldocs`` or ``make pdfdocs``. There are various text files in the Documentation/ subdirectory, several of them using the Restructured Text markup notation. See Documentation/00-INDEX for a list of what is contained in each file. 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.