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authorAaro Koskinen <aaro.koskinen@iki.fi>2013-09-30 23:44:31 +0300
committerRafael J. Wysocki <rafael.j.wysocki@intel.com>2013-10-17 00:56:56 +0200
commit45a428ebbf7d6a4ec77cf02fc706ecd62b261bd9 (patch)
tree28583e2e8230a7a07aeed923b691ccdb9f9a4202 /drivers/cpufreq
parentfbbc5bfb44a22e7a8ef753a1c8dfb448d7ac8b85 (diff)
downloadblackbird-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 'drivers/cpufreq')
-rw-r--r--drivers/cpufreq/pmac64-cpufreq.c6
1 files changed, 3 insertions, 3 deletions
diff --git a/drivers/cpufreq/pmac64-cpufreq.c b/drivers/cpufreq/pmac64-cpufreq.c
index b977b9aa408e..889c0d553572 100644
--- a/drivers/cpufreq/pmac64-cpufreq.c
+++ b/drivers/cpufreq/pmac64-cpufreq.c
@@ -137,7 +137,7 @@ static void g5_vdnap_switch_volt(int speed_mode)
pmf_call_one(pfunc_vdnap0_complete, &args);
if (done)
break;
- msleep(1);
+ usleep_range(1000, 1000);
}
if (done == 0)
printk(KERN_WARNING "cpufreq: Timeout in clock slewing !\n");
@@ -236,7 +236,7 @@ static void g5_pfunc_switch_volt(int speed_mode)
if (pfunc_cpu1_volt_low)
pmf_call_one(pfunc_cpu1_volt_low, NULL);
}
- msleep(10); /* should be faster , to fix */
+ usleep_range(10000, 10000); /* should be faster , to fix */
}
/*
@@ -281,7 +281,7 @@ static int g5_pfunc_switch_freq(int speed_mode)
pmf_call_one(pfunc_slewing_done, &args);
if (done)
break;
- msleep(1);
+ usleep_range(500, 500);
}
if (done == 0)
printk(KERN_WARNING "cpufreq: Timeout in clock slewing !\n");
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