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From: "Chen, Kenneth W" <kenneth.w.chen@intel.com>
To: "'Nick Piggin'" <nickpiggin@yahoo.com.au>,
       "Con Kolivas" <kernel@kolivas.org>
Cc: <linux-kernel@vger.kernel.org>, "'Chris Mason'" <mason@suse.com>,
       "Ingo Molnar" <mingo@elte.hu>
Subject: RE: [PATCH RFC] smt nice introduces significant lock contention
Date: Fri, 2 Jun 2006 01:34:50 -0700
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Nick Piggin wrote on Friday, June 02, 2006 1:29 AM
> Con Kolivas wrote:
> > On Friday 02 June 2006 17:53, Nick Piggin wrote:
> > 
> >>This is a small micro-optimisation / cleanup we can do after
> >>smtnice gets converted to use trylocks. Might result in a little
> >>less cacheline footprint in some cases.
> > 
> > 
> > It's only dependent_sleeper that is being converted in these patches. The 
> > wake_sleeping_dependent component still locks all runqueues and needs to 
> 
> Oh I missed that.
> 
> > succeed in order to ensure a task doesn't keep sleeping indefinitely. That 
> 
> Let's make it use trylocks as well. wake_priority_sleeper should ensure
> things don't sleep forever I think? We should be optimising for the most
> common case, and in many workloads, the runqueue does go idle frequently.
> 

Ha, you beat me by one minute. It did cross my mind to use try lock there as
well, take a look at my version, I think I have a better inner loop.

- Ken