From: "Chuck Lever" Subject: Re: Performance Diagnosis Date: Tue, 15 Jul 2008 12:23:58 -0400 Message-ID: <76bd70e30807150923r31027edxb0394a220bbe879b@mail.gmail.com> References: <487CC928.8070908@redhat.com> Reply-To: chucklever@gmail.com Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Cc: "Andrew Bell" , linux-nfs@vger.kernel.org To: "Peter Staubach" Return-path: Received: from yw-out-2324.google.com ([74.125.46.30]:13534 "EHLO yw-out-2324.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752814AbYGOQYL (ORCPT ); Tue, 15 Jul 2008 12:24:11 -0400 Received: by yw-out-2324.google.com with SMTP id 9so2617200ywe.1 for ; Tue, 15 Jul 2008 09:24:00 -0700 (PDT) In-Reply-To: <487CC928.8070908@redhat.com> Sender: linux-nfs-owner@vger.kernel.org List-ID: On Tue, Jul 15, 2008 at 11:58 AM, Peter Staubach wrote: > If it is the notion described above, sometimes called head > of line blocking, then we could think about ways to duplex > operations over multiple TCP connections, perhaps with one > connection for small, low latency operations, and another > connection for larger, higher latency operations. I've dreamed about that for years. I don't think it would be too difficult, but one thing that has held it back is the shortage of ephemeral ports on the client may reduce the number of concurrent mount points we can support. One way to avoid the port issue is to construct an SCTP transport for NFS. SCTP allows multiple streams on the same connection, effectively eliminating head of line blocking. -- Chuck Lever