From: Viresh Kumar <viresh.kumar@linaro.org> To: Mason <slash.tmp@free.fr> Cc: Russell King - ARM Linux <linux@arm.linux.org.uk>, Daniel Lezcano <daniel.lezcano@linaro.org>, "Rafael J. Wysocki" <rjw@rjwysocki.net>, Mans Rullgard <mans@mansr.com>, Linux ARM <linux-arm-kernel@lists.infradead.org>, Linux PM <linux-pm@vger.kernel.org>, cpufreq <cpufreq@vger.kernel.org> Subject: Re: schedule_timeout sleeps too long after dividing CPU frequency Date: Thu, 14 May 2015 17:24:56 +0530 [thread overview] Message-ID: <20150514115456.GB23999@linux> (raw) In-Reply-To: <5554858A.9010207@free.fr> On 14-05-15, 13:22, Mason wrote: > I didn't /literally/ take a stop-watch to verify it was EXACTLY > 9 seconds, but I was staring at the prompt, and it /felt/ like > 9 seconds. And the 54 second case felt like a minute. :) > I'm using a 27 MHz crystal as clocksource. This is independent > of the CPU frequency. However, I'm using the ARM TWD as the > system's clockevent source, and the TWD's clock is tied to > the CPU clock (PERIPHCLK = CPUCLK / 2 on this SoC). The only (very straight forward) problem is that we aren't propagating the freq update to clockevents core and you need to debug a bit there. Also I wanted to see the source of your print message: [ 19.650454] NEW RATE=9250000 [ 19.653644] NEW RATE=9250000 What's this rate ? Old/new ? Because you are atleast printing the old rate here, and the function by default gets the new rate. > I'm wondering if there's another standard clockevent source > I could try (it would be great if it supported high-resolution > timers). I hope you have some platform general-purpose-timers. -- viresh
WARNING: multiple messages have this Message-ID (diff)
From: viresh.kumar@linaro.org (Viresh Kumar) To: linux-arm-kernel@lists.infradead.org Subject: schedule_timeout sleeps too long after dividing CPU frequency Date: Thu, 14 May 2015 17:24:56 +0530 [thread overview] Message-ID: <20150514115456.GB23999@linux> (raw) In-Reply-To: <5554858A.9010207@free.fr> On 14-05-15, 13:22, Mason wrote: > I didn't /literally/ take a stop-watch to verify it was EXACTLY > 9 seconds, but I was staring at the prompt, and it /felt/ like > 9 seconds. And the 54 second case felt like a minute. :) > I'm using a 27 MHz crystal as clocksource. This is independent > of the CPU frequency. However, I'm using the ARM TWD as the > system's clockevent source, and the TWD's clock is tied to > the CPU clock (PERIPHCLK = CPUCLK / 2 on this SoC). The only (very straight forward) problem is that we aren't propagating the freq update to clockevents core and you need to debug a bit there. Also I wanted to see the source of your print message: [ 19.650454] NEW RATE=9250000 [ 19.653644] NEW RATE=9250000 What's this rate ? Old/new ? Because you are atleast printing the old rate here, and the function by default gets the new rate. > I'm wondering if there's another standard clockevent source > I could try (it would be great if it supported high-resolution > timers). I hope you have some platform general-purpose-timers. -- viresh
next prev parent reply other threads:[~2015-05-14 11:54 UTC|newest] Thread overview: 77+ messages / expand[flat|nested] mbox.gz Atom feed top 2015-05-12 14:32 schedule_timeout sleeps too long after dividing CPU frequency Mason 2015-05-12 14:32 ` Mason 2015-05-12 14:46 ` Viresh Kumar 2015-05-12 14:46 ` Viresh Kumar 2015-05-12 15:14 ` Mason 2015-05-12 15:14 ` Mason 2015-05-12 15:50 ` Russell King - ARM Linux 2015-05-12 15:50 ` Russell King - ARM Linux 2015-05-12 16:14 ` Mason 2015-05-12 16:14 ` Mason 2015-05-13 16:51 ` Mason 2015-05-13 16:51 ` Mason 2015-05-14 2:13 ` Viresh Kumar 2015-05-14 2:13 ` Viresh Kumar 2015-05-14 11:22 ` Mason 2015-05-14 11:22 ` Mason 2015-05-14 11:54 ` Viresh Kumar [this message] 2015-05-14 11:54 ` Viresh Kumar 2015-05-14 13:06 ` Mason 2015-05-14 13:06 ` Mason 2015-05-14 13:53 ` Russell King - ARM Linux 2015-05-14 13:53 ` Russell King - ARM Linux 2015-05-14 14:51 ` Mason 2015-05-14 14:51 ` Mason 2015-05-14 13:59 ` Viresh Kumar 2015-05-14 13:59 ` Viresh Kumar 2015-05-14 13:59 ` Viresh Kumar 2015-05-14 14:38 ` Viresh Kumar 2015-05-14 14:38 ` Viresh Kumar 2015-05-14 14:42 ` Russell King - ARM Linux 2015-05-14 14:42 ` Russell King - ARM Linux 2015-05-15 9:29 ` Mason 2015-05-15 9:29 ` Mason 2015-05-15 9:51 ` Russell King - ARM Linux 2015-05-15 9:51 ` Russell King - ARM Linux 2015-05-15 10:01 ` Viresh Kumar 2015-05-15 10:01 ` Viresh Kumar 2015-05-15 10:36 ` Mason 2015-05-15 10:36 ` Mason 2015-05-15 11:58 ` Russell King - ARM Linux 2015-05-15 11:58 ` Russell King - ARM Linux 2015-05-15 12:45 ` Mason 2015-05-15 12:45 ` Mason 2015-05-15 13:15 ` Russell King - ARM Linux 2015-05-15 13:15 ` Russell King - ARM Linux 2015-05-15 13:58 ` Mason 2015-05-15 18:35 ` Mason 2015-05-18 11:24 ` Mason 2015-05-18 11:54 ` Russell King - ARM Linux 2015-05-20 16:21 ` Mason 2015-05-20 18:50 ` Arnd Bergmann 2015-05-20 19:34 ` Mason 2015-05-20 20:14 ` Russell King - ARM Linux 2015-05-20 20:41 ` Mason 2015-05-20 20:52 ` Arnd Bergmann 2015-05-20 21:56 ` Mason 2015-05-20 22:18 ` Arnd Bergmann 2015-05-21 12:35 ` Mason 2015-05-20 23:14 ` Russell King - ARM Linux 2015-05-21 9:56 ` Mason 2015-05-21 10:20 ` Russell King - ARM Linux 2015-05-14 14:48 ` Mason 2015-05-14 14:48 ` Mason 2015-05-15 4:16 ` Viresh Kumar 2015-05-15 4:16 ` Viresh Kumar 2015-05-15 5:07 ` Viresh Kumar 2015-05-15 5:07 ` Viresh Kumar 2015-05-15 9:00 ` Russell King - ARM Linux 2015-05-15 9:00 ` Russell King - ARM Linux 2015-05-15 9:21 ` Mason 2015-05-15 9:21 ` Mason 2015-05-15 10:11 ` Mason 2015-05-15 10:11 ` Mason 2015-05-12 15:23 ` Russell King - ARM Linux 2015-05-12 15:23 ` Russell King - ARM Linux 2015-05-12 16:03 ` Mason 2015-05-12 16:03 ` Mason
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