From mboxrd@z Thu Jan 1 00:00:00 1970 From: markw@osdl.org Date: Fri, 26 Mar 2004 17:16:52 +0000 Subject: Re: should ia64_spinlock_contention do backoff? Message-Id: <200403261716.i2QHGt205909@mail.osdl.org> List-Id: References: <200403251941.i2PJfrTH026392@napali.hpl.hp.com> In-Reply-To: <200403251941.i2PJfrTH026392@napali.hpl.hp.com> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: linux-ia64@vger.kernel.org On 25 Mar, David Mosberger wrote: > Has anyone studied the impact of doing exponential backoff in > ia64_spinlock_contention. My theory is that it wouldn't buy much _if_ > spinlocks always were in their own cachelines, but since they're not, > not using backoff could cause extra cache-line bouncing. To be > honest, I'd rather not spend time on this myself, since I don't have > convenient access to large machines, but me thinks this is a question > that's long overdue to have a proper answer. We have 4-way Itanium2 systems here. Is that large enough for testing? Mark