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the timing facilities in LKET
- From: "Gui,Jian" <guij at cn dot ibm dot com>
- To: systemtap at sources dot redhat dot com
- Date: Mon, 14 Aug 2006 15:20:26 +0800
- Subject: the timing facilities in LKET
Based on the discussions a couple of days ago, we plan to implement
the timing facilities as follow:
1) keep current do_gettimeofday;
2) Use get_cycles, trace the variation of cpu frequency and let the
postprocessing translate cycles into seconds.microseconds.
The default is to use get_cycles, but we can also change it like:
probe begin
{
set_timing_method(2); //e.g. get_cycles is 1, do_gettimeofday is 2
}
Actually, sched_clock should be a better choice but it is not exported
out of kernel yet. We'd like to use get_cycles first and see how to
integrate sched_clock into LKET/systemtap better.
Any comments? Thanks.