aboutsummaryrefslogtreecommitdiffstats
path: root/include/trace
diff options
context:
space:
mode:
authorLi Zefan <lizf@cn.fujitsu.com>2010-07-02 11:07:32 +0800
committerSteven Rostedt <rostedt@goodmis.org>2010-07-20 21:52:33 -0400
commite870e9a1240bcef1157ffaaf71dac63362e71904 (patch)
treeb8f57a68ff45b35dab8cdfa474e17622d275bdc6 /include/trace
parentcc5edb0eb9ce892b530e34a5d110382483587942 (diff)
tracing: Allow to disable cmdline recording
We found that even enabling a single trace event that will rarely be triggered can add big overhead to context switch. (lmbench context switch test) ------------------------------------------------- 2p/0K 2p/16K 2p/64K 8p/16K 8p/64K 16p/16K 16p/64K ctxsw ctxsw ctxsw ctxsw ctxsw ctxsw ctxsw ------ ------ ------ ------ ------ ------- ------- 2.19 2.3 2.21 2.56 2.13 2.54 2.07 2.39 2.51 2.35 2.75 2.27 2.81 2.24 The overhead is 6% ~ 11%. It's because when a trace event is enabled 3 tracepoints (sched_switch, sched_wakeup, sched_wakeup_new) will be activated to map pid to cmdname. We'd like to avoid this overhead, so add a trace option '(no)record-cmd' to allow to disable cmdline recording. Signed-off-by: Li Zefan <lizf@cn.fujitsu.com> LKML-Reference: <4C2D57F4.2050204@cn.fujitsu.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Diffstat (limited to 'include/trace')
0 files changed, 0 insertions, 0 deletions

Privacy Policy