From mboxrd@z Thu Jan 1 00:00:00 1970 From: jbarnes@sgi.com (Jesse Barnes) Date: Tue, 22 Jul 2003 13:11:54 +0000 Subject: Re: [PATCH] don't use ld.bias Message-Id: List-Id: References: In-Reply-To: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: linux-ia64@vger.kernel.org On Mon, Jul 21, 2003 at 05:15:39PM -0700, Chen, Kenneth W wrote: > > Patch to fix spin_lock to not use ld.bias since it causes a bunch of > bus > > activity that hurts scalability when a lock is contended. > > It's dangerous to say something without knowing the whole context, but I > can't resist asking why not fix the contended lock area instead? Sounds > like you have some serious contention. Maybe I shouldn't have said 'contended'. This causes problems even when a lock is nearly uncontended. I agree that fixing lock contention is a good idea, but as I read this code, it'll only make the very best case (totally uncontended) only a little better than if the ld.bias were just an ld and it makes the average and contended cases _much_ worse. I can get some data if you're not convinced by reading the code :) Thanks, Jesse