From: tony@atomide.com (Tony Lindgren)
To: linux-arm-kernel@lists.infradead.org
Subject: One of these things (CONFIG_HZ) is not like the others..
Date: Mon, 21 Jan 2013 15:23:22 -0800 [thread overview]
Message-ID: <20130121232322.GK15361@atomide.com> (raw)
In-Reply-To: <20130121210341.GW23505@n2100.arm.linux.org.uk>
* Russell King - ARM Linux <linux@arm.linux.org.uk> [130121 13:07]:
>
> As for Samsung and the rest I can't comment. The original reason OMAP
> used this though was because the 32768Hz counter can't produce 100Hz
> without a .1% error - too much error under pre-clocksource
> implementations for timekeeping. Whether that's changed with the
> clocksource/clockevent support needs to be checked.
Yes that's why HZ was originally set to 128. That value (or some multiple)
still makes sense when the 32 KiHZ clock source is being used. Of course
we should rely on the local timer when running for the SoCs that have
them.
Regards,
Tony
WARNING: multiple messages have this Message-ID (diff)
From: Tony Lindgren <tony@atomide.com>
To: Russell King - ARM Linux <linux@arm.linux.org.uk>
Cc: Arnd Bergmann <arnd@arndb.de>, Matt Sealey <matt@genesi-usa.com>,
Linux ARM Kernel ML <linux-arm-kernel@lists.infradead.org>,
LKML <linux-kernel@vger.kernel.org>,
Peter Zijlstra <peterz@infradead.org>,
Ingo Molnar <mingo@redhat.com>,
John Stultz <john.stultz@linaro.org>,
Ben Dooks <ben@simtec.co.uk>
Subject: Re: One of these things (CONFIG_HZ) is not like the others..
Date: Mon, 21 Jan 2013 15:23:22 -0800 [thread overview]
Message-ID: <20130121232322.GK15361@atomide.com> (raw)
In-Reply-To: <20130121210341.GW23505@n2100.arm.linux.org.uk>
* Russell King - ARM Linux <linux@arm.linux.org.uk> [130121 13:07]:
>
> As for Samsung and the rest I can't comment. The original reason OMAP
> used this though was because the 32768Hz counter can't produce 100Hz
> without a .1% error - too much error under pre-clocksource
> implementations for timekeeping. Whether that's changed with the
> clocksource/clockevent support needs to be checked.
Yes that's why HZ was originally set to 128. That value (or some multiple)
still makes sense when the 32 KiHZ clock source is being used. Of course
we should rely on the local timer when running for the SoCs that have
them.
Regards,
Tony
next prev parent reply other threads:[~2013-01-21 23:23 UTC|newest]
Thread overview: 96+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-01-21 20:01 One of these things (CONFIG_HZ) is not like the others Matt Sealey
2013-01-21 20:01 ` Matt Sealey
2013-01-21 20:41 ` Arnd Bergmann
2013-01-21 20:41 ` Arnd Bergmann
2013-01-21 21:00 ` John Stultz
2013-01-21 21:00 ` John Stultz
2013-01-21 21:12 ` Russell King - ARM Linux
2013-01-21 21:12 ` Russell King - ARM Linux
2013-01-21 22:18 ` John Stultz
2013-01-21 22:18 ` John Stultz
2013-01-21 22:44 ` Russell King - ARM Linux
2013-01-21 22:44 ` Russell King - ARM Linux
2013-01-22 8:27 ` Arnd Bergmann
2013-01-22 8:27 ` Arnd Bergmann
2013-01-21 22:20 ` Matt Sealey
2013-01-21 22:20 ` Matt Sealey
2013-01-21 22:42 ` Russell King - ARM Linux
2013-01-21 22:42 ` Russell King - ARM Linux
2013-01-21 23:23 ` Matt Sealey
2013-01-21 23:23 ` Matt Sealey
2013-01-21 23:49 ` Russell King - ARM Linux
2013-01-21 23:49 ` Russell King - ARM Linux
2013-01-22 0:09 ` Matt Sealey
2013-01-22 0:09 ` Matt Sealey
2013-01-22 0:26 ` Matt Sealey
2013-01-22 0:26 ` Matt Sealey
2013-01-21 21:14 ` Matt Sealey
2013-01-21 21:14 ` Matt Sealey
2013-01-21 22:36 ` John Stultz
2013-01-21 22:36 ` John Stultz
2013-01-21 22:49 ` Russell King - ARM Linux
2013-01-21 22:49 ` Russell King - ARM Linux
2013-01-21 22:54 ` Matt Sealey
2013-01-21 22:54 ` Matt Sealey
2013-01-21 23:13 ` Russell King - ARM Linux
2013-01-21 23:13 ` Russell King - ARM Linux
2013-01-21 23:30 ` Matt Sealey
2013-01-21 23:30 ` Matt Sealey
2013-01-22 0:02 ` Russell King - ARM Linux
2013-01-22 0:02 ` Russell King - ARM Linux
2013-01-22 0:38 ` John Stultz
2013-01-22 0:38 ` John Stultz
2013-01-22 0:51 ` John Stultz
2013-01-22 0:51 ` John Stultz
2013-01-22 1:06 ` Matt Sealey
2013-01-22 1:06 ` Matt Sealey
2013-01-22 1:18 ` Russell King - ARM Linux
2013-01-22 1:18 ` Russell King - ARM Linux
2013-01-22 1:56 ` Matt Sealey
2013-01-22 1:56 ` Matt Sealey
2013-01-22 1:31 ` John Stultz
2013-01-22 1:31 ` John Stultz
2013-01-22 2:10 ` Matt Sealey
2013-01-22 2:10 ` Matt Sealey
2013-01-31 21:31 ` Thomas Gleixner
2013-01-31 21:31 ` Thomas Gleixner
2013-01-21 21:02 ` Matt Sealey
2013-01-21 21:02 ` Matt Sealey
2013-01-21 22:30 ` Arnd Bergmann
2013-01-21 22:30 ` Arnd Bergmann
2013-01-21 22:45 ` Russell King - ARM Linux
2013-01-21 22:45 ` Russell King - ARM Linux
2013-01-21 23:01 ` Matt Sealey
2013-01-21 23:01 ` Matt Sealey
2013-01-21 21:03 ` Russell King - ARM Linux
2013-01-21 21:03 ` Russell King - ARM Linux
2013-01-21 23:23 ` Tony Lindgren [this message]
2013-01-21 23:23 ` Tony Lindgren
2013-01-22 6:23 ` Santosh Shilimkar
2013-01-22 6:23 ` Santosh Shilimkar
2013-01-22 9:31 ` Arnd Bergmann
2013-01-22 9:31 ` Arnd Bergmann
2013-01-22 10:14 ` Santosh Shilimkar
2013-01-22 10:14 ` Santosh Shilimkar
2013-01-22 14:51 ` Russell King - ARM Linux
2013-01-22 14:51 ` Russell King - ARM Linux
2013-01-22 15:05 ` Santosh Shilimkar
2013-01-22 15:05 ` Santosh Shilimkar
2013-01-28 6:08 ` Santosh Shilimkar
2013-01-28 6:08 ` Santosh Shilimkar
2013-01-29 0:01 ` John Stultz
2013-01-29 0:01 ` John Stultz
2013-01-29 6:43 ` Santosh Shilimkar
2013-01-29 6:43 ` Santosh Shilimkar
2013-01-29 10:06 ` Russell King - ARM Linux
2013-01-29 10:06 ` Russell King - ARM Linux
2013-01-29 18:43 ` John Stultz
2013-01-29 18:43 ` John Stultz
2013-01-22 17:31 ` Arnd Bergmann
2013-01-22 17:31 ` Arnd Bergmann
2013-01-22 18:59 ` John Stultz
2013-01-22 18:59 ` John Stultz
2013-01-22 21:52 ` Tony Lindgren
2013-01-22 21:52 ` Tony Lindgren
2013-01-23 5:18 ` Santosh Shilimkar
2013-01-23 5:18 ` Santosh Shilimkar
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