From mboxrd@z Thu Jan 1 00:00:00 1970 From: Matthew Wilcox Date: Wed, 23 Jul 2003 12:00:15 +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 Tue, Jul 22, 2003 at 09:40:02PM -0700, Mallick, Asit K wrote: > It does make sense to not use the ld.bias in the spinlock, it will make > more cacheline bouncing in a larger SMP system. it certainly makes a mockery of the comment: * Streamlined test_and_set_bit(0, (x)). We use test-and-test-and-set * rather than a simple xchg to avoid writing the cache-line when * there is contention. since there's no real advantage (AIUI) to have the cacheline clean-exclusive vs dirty-exclusive. but why not delete this code? it's under #else /* !NEW_LOCK */ and NEW_LOCK looks to be the better code as well as the default in 2.5. -- "It's not Hollywood. War is real, war is primarily not about defeat or victory, it is about death. I've seen thousands and thousands of dead bodies. Do you think I want to have an academic debate on this subject?" -- Robert Fisk