From mboxrd@z Thu Jan 1 00:00:00 1970 From: Eric Van Hensbergen Subject: Re: [V9fs-developer] :[RFC] [PATCH 6/7] [net/9p] Read and Write side zerocopy changes for 9P2000.L protocol. Date: Wed, 9 Feb 2011 08:28:13 -0600 Message-ID: References: <1297063283-2180-1-git-send-email-jvrao@linux.vnet.ibm.com> <1297063283-2180-7-git-send-email-jvrao@linux.vnet.ibm.com> <4D4F97ED.9070401@linux.vnet.ibm.com> <4D51D6D0.6040200@linux.vnet.ibm.com> <4D51F514.2060800@linux.vnet.ibm.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Cc: linux-fsdevel@vger.kernel.org, v9fs-developer@lists.sourceforge.net To: "Venkateswararao Jujjuri (JV)" Return-path: Received: from mail-fx0-f46.google.com ([209.85.161.46]:52436 "EHLO mail-fx0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754929Ab1BIO2O (ORCPT ); Wed, 9 Feb 2011 09:28:14 -0500 Received: by fxm20 with SMTP id 20so245915fxm.19 for ; Wed, 09 Feb 2011 06:28:13 -0800 (PST) In-Reply-To: <4D51F514.2060800@linux.vnet.ibm.com> Sender: linux-fsdevel-owner@vger.kernel.org List-ID: On Tue, Feb 8, 2011 at 7:59 PM, Venkateswararao Jujjuri (JV) wrote: >> >>> the implementations it should be really easy to shut me up with >>> comparison data of zc and non-zc for 1, 64, 128, 256, 512, 1024, 2048, >>> 4192 byte payloads (without caches enabled of course). >> >> I think this is good experiment will publish data. > > BTW, unless we have bigger msize with differentiating pdu sizes these experiments > may not make sense. > Not sure I agree (at least in the 1-4k scale), we are measuring the overhead of memcpy versus the overhead of mapping/pinning the additional sg -- or am I not thinking clearly. Its possible... I have not had coffee yet. I suppose with your small buffer patch series there might be some performance differences due to different allocator behavior, and while I don't think it'll be significant, it may be worth re-doing the experiment once we have that in place. Which brings up another question -- I know your team are doing functional regressions, but are they also dong performance regressions? Since we are starting into the optimization patches it may not be a bad idea to track how the changes are impacting scalability, latency, and throughput (as well as some metric of resource consumption, but that may be a harder metric to track). -eric -eric