Subject: ARM perf events spin locks

From: [email-masked] (Jamie Iles)
Date: Tue, 30 Nov 2010 10:58:56 +0000

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