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| author | Aaro Koskinen <aaro.koskinen@iki.fi> | 2013-09-30 23:44:31 +0300 |
|---|---|---|
| committer | Rafael J. Wysocki <rafael.j.wysocki@intel.com> | 2013-10-17 00:56:56 +0200 |
| commit | 45a428ebbf7d6a4ec77cf02fc706ecd62b261bd9 (patch) | |
| tree | 28583e2e8230a7a07aeed923b691ccdb9f9a4202 /arch | |
| parent | fbbc5bfb44a22e7a8ef753a1c8dfb448d7ac8b85 (diff) | |
| download | blackbird-op-linux-45a428ebbf7d6a4ec77cf02fc706ecd62b261bd9.tar.gz blackbird-op-linux-45a428ebbf7d6a4ec77cf02fc706ecd62b261bd9.zip | |
cpufreq: pmac64: speed up frequency switch
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@iki.fi>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Acked-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Diffstat (limited to 'arch')
0 files changed, 0 insertions, 0 deletions
