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From: linux@arm.linux.org.uk (Russell King - ARM Linux)
To: linux-arm-kernel@lists.infradead.org
Subject: sched_clock always 0 and no process time accounting with 3.11-rc1
Date: Wed, 17 Jul 2013 10:15:19 +0100	[thread overview]
Message-ID: <20130717091519.GL24642@n2100.arm.linux.org.uk> (raw)
In-Reply-To: <20130717091209.GL6950@tarshish>

On Wed, Jul 17, 2013 at 12:12:09PM +0300, Baruch Siach wrote:
> Hi Russell,
> 
> On Wed, Jul 17, 2013 at 10:03:55AM +0100, Russell King - ARM Linux wrote:
> > On Wed, Jul 17, 2013 at 09:19:25AM +0300, Baruch Siach wrote:
> > > Apparently the expression '(1 << 32)' evaluates to 1 on xtensa cross gcc, and 
> > > x86_84 native gcc. According to my limited understanding, the C compiler is 
> > > allowed to do so. This caused sched_clock_32() to return constant 0. I wonder 
> > > how it didn't bite the ARM people who are using this code from quite some time 
> > > (added LAKL to CC).
> > 
> > It (a) used to be only 32-bit, and (b) <<32 on ARM evaluates to zero in
> > a 32-bit context (it's not a rotate).
> > 
> > Patch looks fine.
> 
> Thanks for the confirmation, I'll take it as an ack if you don't mind.

If you want it as an ack, use rmk+kernel at arm.linux.org.uk as the email
address please.

  reply	other threads:[~2013-07-17  9:15 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <CAMo8BfLO31GgMMA_hENr0xm=qaUz3EVLtaQ8hewiQHdbV+s6sA@mail.gmail.com>
2013-07-17  6:19 ` sched_clock always 0 and no process time accounting with 3.11-rc1 Baruch Siach
2013-07-17  6:39   ` Max Filippov
2013-07-17  6:47     ` [Linux-Xtensa] " Baruch Siach
2013-07-17  7:02       ` Chris Zankel
2013-07-17  7:14         ` Baruch Siach
2013-07-17  9:03   ` Russell King - ARM Linux
2013-07-17  9:12     ` Baruch Siach
2013-07-17  9:15       ` Russell King - ARM Linux [this message]
2013-07-17 15:15   ` [Linux-Xtensa] " Marc Gauthier
2013-07-17 15:24     ` Russell King - ARM Linux
2013-07-17 16:17       ` Marc Gauthier

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