diff options
| author |   Alexey Budankov <alexey.budankov@linux.intel.com> | 2018-11-06 12:07:19 +0300 |
|---|---|---|
| committer |   Arnaldo Carvalho de Melo <acme@redhat.com> | 2018-12-17 14:55:11 -0300 |
| commit | 93f20c0fe3e86088ec041e47755367c4bed584c6 (patch) | |
| tree | 108d59a511a822fa122db8371b2b49e243b885e9 /tools/perf/Documentation/perf-record.txt | |
| parent | perf record: Enable asynchronous trace writing (diff) | |
| download | linux-dev-93f20c0fe3e86088ec041e47755367c4bed584c6.tar.xz linux-dev-93f20c0fe3e86088ec041e47755367c4bed584c6.zip | |
perf record: Extend trace writing to multi AIO
Multi AIO trace writing allows caching more kernel data into userspace
memory postponing trace writing for the sake of overall profiling data
thruput increase. It could be seen as kernel data buffer extension into
userspace memory.
With an --aio option value different from 0 (default value is 1) the
tool has capability to cache more and more data into user space along
with delegating spill to AIO.
That allows avoiding to suspend at record__aio_sync() between calls of
record__mmap_read_evlist() and increases profiling data thruput at the
cost of userspace memory.
Signed-off-by: Alexey Budankov <alexey.budankov@linux.intel.com>
Reviewed-by: Jiri Olsa <jolsa@redhat.com>
Acked-by: Namhyung Kim <namhyung@kernel.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/050bb053-e7f3-aa83-fde7-f27ff90be7f6@linux.intel.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Diffstat (limited to 'tools/perf/Documentation/perf-record.txt')
| -rw-r--r-- | tools/perf/Documentation/perf-record.txt | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/tools/perf/Documentation/perf-record.txt b/tools/perf/Documentation/perf-record.txt index 7efb4af88a68..d232b13ea713 100644 --- a/tools/perf/Documentation/perf-record.txt +++ b/tools/perf/Documentation/perf-record.txt @@ -435,8 +435,8 @@ Specify vmlinux path which has debuginfo. --buildid-all:: Record build-id of all DSOs regardless whether it's actually hit or not. ---aio:: -Enable asynchronous (Posix AIO) trace writing mode. +--aio[=n]:: +Use <n> control blocks in asynchronous (Posix AIO) trace writing mode (default: 1, max: 4). Asynchronous mode is supported only when linking Perf tool with libc library providing implementation for Posix AIO API. |