On 15 December 2011 13:06, Linus Walleij <linus.wall...@linaro.org> wrote: > On Thu, Dec 15, 2011 at 1:16 PM, Daniel Lezcano > <daniel.lezc...@linaro.org> wrote: >> [Me] >>>> It is easy to reproduce with 'time sleep 1' where the timer expires 1, 2 >>>> or 3 seconds later. >>>> >>>> It seems that does not happen with linux-linaro-3.1 but I was able to >>>> reproduce the problem on a vanilla kernel 3.1.5. >>>> >>>> Is it a known problem ? >>> >>> Sleeps are only guaranteed at max speed. >> >> I am not sure to get the point. Do you mean cpufreq max frequency ? > > It means that the kernel idea of sleep(1) is, sleep atleast 1 second, > possibly more. When the system scales down frequency, say to half > the frequency, things start to take twice the time. So sleep(1) may > result in 2 seconds of sleep or so.
In that situation will multiple sleep's on different CPUs behave consistently or could they take wildly different amounts of time? > The patches below are intended to address this... I wonder if this is my problem with membase; I'll try and give it a go. In particular it has a testsuite that's designed to exercise it's data expiry mechanism, where it stores some data telling it to expire it in 1 seconds time, then the test suite has a 2 second sleep, and then sees if the data is still there - which it is some annoyingly small fraction of the time. Dave _______________________________________________ linaro-dev mailing list linaro-dev@lists.linaro.org http://lists.linaro.org/mailman/listinfo/linaro-dev
