From mboxrd@z Thu Jan 1 00:00:00 1970 From: Robin Holt Date: Thu, 20 Nov 2003 19:23:18 +0000 Subject: Re: [PATCH] - sched_clock() broken for ia64 SN platform 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 Thu, Nov 20, 2003 at 10:32:29AM -0800, David Mosberger wrote: > >>>>> On Thu, 20 Nov 2003 09:23:35 -0600, Jack Steiner said: > > Jack> This is slightly off-topic, but the shared platform counter on > Jack> the SGI platform isnt a single counter. The counter is > Jack> replicated in each chipset It is synchronized thruout the > Jack> system so that all cpus will see the same value - ie., no > Jack> drift. Reading the counter does not required any off-node > Jack> references. There shouldnt be any scaling issues. > > Ah, that's good. Just for future reference, what's the approximate > latency of reading this counter? I haven't tested it recently, but it was approx 55nSec on a 900Mhz Madison.