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 15:20:58 +0000 [thread overview]
Message-ID: <20130322152057.GE4977@n2100.arm.linux.org.uk> (raw)
In-Reply-To: <514C557F.1090101@gmail.com>
On Fri, Mar 22, 2013 at 07:58:39AM -0500, Rob Herring wrote:
> The ARM ARM also says the roll-over time must be greater than 40 years.
> So if you have fewer bits, then it needs to run at lower frequency. So I
> think we should be fine.
Well, we have a problem with 32-bit systems in about 19 years time when
32-bit Unix timestamps wrap. Of course, by that time we'll all be
64-bit won't we. :)
Another issue here is whether it's likely that a system will have an
uptime of 40+ years. Probably not. The longest I can think of which
I have come across is the digital public address system on the London
Jubilee Line (Waterloo to Stratford section) which was specified to
have a life of 20 to 30 years... Hmm, I wonder of my Linux based system
activity logger is still in the Stratford PA racks. :)
next prev parent reply other threads:[~2013-03-22 15:20 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 [this message]
2013-03-22 11:09 ` Russell King - ARM Linux
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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