Messages in this thread |  | | Date | Fri, 9 May 2003 09:53:59 -0700 | From | William Lee Irwin III <> | Subject | Re: how to measure scheduler latency on powerpc? realfeel doesn't work due to /dev/rtc issues |
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On Fri, 2003-05-09 at 03:01, William Lee Irwin III wrote: >> Why not just keep track of it in the scheduler? The statistic is well- >> defined in terms of things measurable at context switch and wakeup.
On Fri, May 09, 2003 at 12:47:05PM -0400, Robert Love wrote: > This would measure context switch latency. Or something. > By definition, scheduling latency is the time from an interrupt which > wakes the task up until the task is actually running. > Historically, it has been measured by things like realfeel or amlat or > whatever which generate interrupts and wake a waiting task up. You then > measure the latency between the interrupt and when the task actually > runs in user-space. > So Chris can then go run this test under varying loads and see how bad > the latency gets. I understand his question, but (sorry Chris) I have > no idea of the solution on PPC.
Not at all. Just stamp at wakeup and difference when it runs.
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