From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Mosberger Date: Tue, 18 Jan 2005 18:31:10 +0000 Subject: Re: pipe performance regression on ia64 Message-Id: <16877.21998.984277.551515@napali.hpl.hp.com> List-Id: References: <200501181741.j0IHfGf30058@unix-os.sc.intel.com> In-Reply-To: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: Linus Torvalds Cc: "Luck, Tony" , linux-ia64@vger.kernel.org, linux-kernel@vger.kernel.org >>>>> On Tue, 18 Jan 2005 10:11:26 -0800 (PST), Linus Torvalds said: Linus> I don't know how to make the benchmark look repeatable and Linus> good, though. The CPU affinity thing may be the right thing. Perhaps it should be split up into three cases: - producer/consumer pinned to the same CPU - producer/consumer pinned to different CPUs - producer/consumer lefter under control of the scheduler The first two would let us observe any changes in the actual pipe code, whereas the 3rd case would tell us which case the scheduler is leaning towards (or if it starts doing something real crazy, like reschedule the tasks on different CPUs each time, we'd see a bandwith lower than case 2 and that should ring alarm bells). --david