-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 On 12/16/2011 12:23 AM, Linus Walleij wrote: > On Thu, Dec 15, 2011 at 8:02 PM, john stultz <johns...@us.ibm.com> wrote: >> On Thu, 2011-12-15 at 14:06 +0100, Linus Walleij wrote: >>> 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. >> >> Just a minor clarification: So, while Linus is right that sleep can >> validly go longer then the requested time (the only promise is that it >> shouldn't return success early), sleep() should be timer based (not >> delay based), so even if the frequency drops, you *shouldn't* see freq >> proportional delays. > > True. So what the three patches to the SMP_TWD is try to fix that > for the localtimers on these ARM systems, but sadly that doesn't > seem to cut it :-( > >> If that were happening, it would seem timekeeping would also be slowed >> down, which def shouldn't happen if we're using a sane clocksource >> (although broken clocksources - which may change freq with the cpu - >> have caused symptoms like the above). > > Yes skew in the clocksource would sort of affect the ruler that > you're using giving such phenomena. > > The ux500 supports two different clock sources, so Daniel, > what happens if you just reactivate CPUfreq then use menuconfig > to go into drivers/ directly you will see the > "Clocksource PRCMU Timer" (sorry the clksrc subsystem does not > have its own submenu...), deselect that so as to use the > more monotone MTU clock source (it lives up in > arch/arm/plat-nomadik/timer.c by the way), what happens?
I am still seeing the problem ... :/ > If that solves it, reactivate the PRCMU clock source and just > deselect the "clocksource PRCMU timer sched_clock" > and see what happens. > > This way we can see if the PRCMU clock source is causing > it, or if it's simply caused by using the PRCMU for sched_clock > or if neither is causing it. > > Yours, > Linus Walleij - -- <http://www.linaro.org/> Linaro.org ? Open source software for ARM SoCs Follow Linaro: <http://www.facebook.com/pages/Linaro> Facebook | <http://twitter.com/#!/linaroorg> Twitter | <http://www.linaro.org/linaro-blog/> Blog -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.11 (GNU/Linux) Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org/ iQEcBAEBAgAGBQJO6t17AAoJEAKBbMCpUGYAURcH+wX9PadxwkoUraAniAciGRkr aSm+DsETliyDk/q+kcEUImb1QZNsQ2GfHDa0/WA2ksOddLx4LCCmvGJFr7ZVaAk5 DGHb9l2oQ6BoD1jyhHGLya1cGPuNTrxuGCvawfkMWELlnHAqOPp3jzP/ZFHYKQDn naE+9X8f8mPPSTcNDwSZ6zBocxLV1muktDQtZXRqxPfwyHWwogLTJXzEClQW5YR/ gJEZzlpiPc2F5esV46IDV7Zz68dv4wADw23RjmKfry9z9NjBCKq2Lq6uQOwdZSA0 7NfyEBbGyJ9WKOhS1hyjSFRzTD3io2KHnI5JQKweGwACg/TMKVNZdGCgSkgqiZk= =5wnU -----END PGP SIGNATURE----- _______________________________________________ linaro-dev mailing list linaro-dev@lists.linaro.org http://lists.linaro.org/mailman/listinfo/linaro-dev
