[PATCH 1/3] cpufreq: pmac64: speed up frequency switch

Viresh Kumar viresh.kumar at linaro.org
Wed Jul 24 15:32:22 EST 2013


On 24 July 2013 01:54, Aaro Koskinen <aaro.koskinen at iki.fi> wrote:
> Some functions on switch path use msleep() which is inaccurate, and
> depends on HZ. With HZ=100 msleep(1) takes actually over ten times longer.
> Using usleep_range() we get more accurate sleeps.
>
> I measured the "pfunc_slewing_done" polling to take 300us at max (on
> 2.3GHz dual-processor Xserve G5), so using 500us sleep there should
> be fine.
>
> With the patch, g5_switch_freq() duration drops from ~50ms to ~10ms on
> Xserve with HZ=100.
>
> Signed-off-by: Aaro Koskinen <aaro.koskinen at iki.fi>
> ---
>  drivers/cpufreq/pmac64-cpufreq.c | 6 +++---
>  1 file changed, 3 insertions(+), 3 deletions(-)

Looks fine to me as well..

Acked-by: Viresh Kumar <viresh.kumar at linaro.org>


More information about the Linuxppc-dev mailing list