On Mon, Feb 27, 2006 at 06:09:26PM +0200, Vlad GALU wrote:
I wrote a piece of software that has to get the current
timestamp, one way or the other, a huge number of times per second.
Apart from the empyrical tests one can perform to find out the
timekeeping scheme with the less performance impact, is there any rule
of thumb as to what choice to go for ?
The TSC is always fastest, but unfortunately under some circumstances
it can't be trusted (if your CPU has throttle modes to save power
or on some SMP systems where the two TSCs in each CPU give different
values).
David.
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RE: [patch 1/] timers: tsc using for cpu scheduling ...cpu to brother which wait mutex unlock and will do the same. ... the number of cpu clocks spent for considered task/thread for priority... It is not need to modify TSC tick rate for cpu scheduling. ... Linux will use TSC for CPU scheduler priority calculatin.... (Linux-Kernel)
Re: [PATCH] Add an offset in the cyc2ns computation to fix sched_clock jumps ...synchronized TSC.... takes too long to access and is not enabled before the scheduler.... - Takes about 225 cycles per TSC read instead of 181. ... Can get a much better time precision by sending an IPI to each CPU... (Linux-Kernel)
RE: [patch 1/] timers: tsc using for cpu scheduling ... > cpu to brother which wait mutex unlock and will do the same. ... I'm just asking if using the TSC... I'm not a scheduler guy, so forgive my ignorance, but since the TSC may ... That's fine if its what you propose, I just didn't see it in your patch.... (Linux-Kernel)
RE: [patch 1/] timers: tsc using for cpu scheduling ... I should underline that patch deal with the alternative which timer to ... time as a measure of CPU work for scheduling is described in the Linux ... scheduling time measurement because TSC may miss 2-3 clocks during CPU ... * It is not recommended to use this function for other than scheduler... (Linux-Kernel)
