From mboxrd@z Thu Jan  1 00:00:00 1970
From: jamie@jamieiles.com (Jamie Iles)
Date: Tue, 30 Nov 2010 10:58:56 +0000
Subject: ARM perf events spin locks
In-Reply-To: <004101cb907b$16f911b0$44eb3510$@deacon@arm.com>
References: <20101130100802.GB4398@pulham.picochip.com>
	<004101cb907b$16f911b0$44eb3510$@deacon@arm.com>
Message-ID: <20101130105856.GC4398@pulham.picochip.com>
To: linux-arm-kernel@lists.infradead.org
List-Id: linux-arm-kernel.lists.infradead.org

On Tue, Nov 30, 2010 at 10:41:04AM -0000, Will Deacon wrote:
> > Hi Will,
> 
> Hello,
> 
> > I think we should convert the spinlocks in the ARM perf events code to raw
> > spinlocks for realtime. Should we wait for your split set to get merged first
> > before doing this?
> 
> Since this is a logically separate change, I think we're better off waiting
> until the split stuff has been merged. As for the raw spinlocks, by realtime
> do you mean PREEMPT_RT? Also, do we actually *need* raw spinlocks in the perf
> code?
Yes, I meant PREEMPT_RT. It won't stop working without raw spinlocks but I'm 
not convinced that we couldn't lose too much accuracy with normal spinlocks. I 
am however willing to be convinced otherwise!

Jamie