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From: linux@arm.linux.org.uk (Russell King - ARM Linux)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH 2/3] ARM: sched_clock: support 64-bit counters
Date: Fri, 22 Mar 2013 11:09:07 +0000	[thread overview]
Message-ID: <20130322110907.GY4977@n2100.arm.linux.org.uk> (raw)
In-Reply-To: <514B1311.20308@codeaurora.org>

On Thu, Mar 21, 2013 at 10:02:57AM -0400, Christopher Covington wrote:
> To be more precise, architected timers are anywhere between 56 and 64 bits
> wide, zero-extended to 64-bits. See section B8.1.1 of the ARM ARM rev C.b. I
> don't know if the code really needs to change until someone has a need to
> distinguish more finely between timers, but if you're using access size as an
> approximation for counter width, I feel like it at least deserves a mention in
> the comments.

If the counter is such that it doesn't produce a full 64-bit nsec value
from sched_clock(), then it needs to be extended to 64-bit.

  parent reply	other threads:[~2013-03-22 11:09 UTC|newest]

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-03-12  2:26 [PATCH 0/3] ARM sched_clock selection enhancements Rob Herring
2013-03-12  2:26 ` [PATCH 1/3] ARM: sched_clock: allow changing to higher frequency counter Rob Herring
2013-03-12  2:26 ` [PATCH 2/3] ARM: sched_clock: support 64-bit counters Rob Herring
2013-03-21 14:02   ` Christopher Covington
2013-03-21 22:15     ` Rob Herring
2013-03-22 12:03       ` Christopher Covington
2013-03-22 12:58         ` Rob Herring
2013-03-22 15:20           ` Russell King - ARM Linux
2013-03-22 11:09     ` Russell King - ARM Linux [this message]
2013-03-12  2:26 ` [PATCH 3/3] ARM: arch_timer: use the 64-bit sched_clock setup Rob Herring
2013-03-12  9:23 ` [PATCH 0/3] ARM sched_clock selection enhancements Russell King - ARM Linux
2013-03-12 12:43   ` Rob Herring
2013-03-20 23:03     ` Rob Herring

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