From owner-freebsd-stable Thu Jul 25 16:26:52 2002 Delivered-To: freebsd-stable@freebsd.org Received: from mx1.FreeBSD.org (mx1.FreeBSD.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id 9787D37B400 for ; Thu, 25 Jul 2002 16:26:48 -0700 (PDT) Received: from apollo.backplane.com (apollo.backplane.com [216.240.41.2]) by mx1.FreeBSD.org (Postfix) with ESMTP id 2C2BB43E3B for ; Thu, 25 Jul 2002 16:26:48 -0700 (PDT) (envelope-from dillon@apollo.backplane.com) Received: from apollo.backplane.com (localhost [127.0.0.1]) by apollo.backplane.com (8.12.5/8.12.4) with ESMTP id g6PNQlCV035613; Thu, 25 Jul 2002 16:26:47 -0700 (PDT) (envelope-from dillon@apollo.backplane.com) Received: (from dillon@localhost) by apollo.backplane.com (8.12.5/8.12.4/Submit) id g6PNQl5F035612; Thu, 25 Jul 2002 16:26:47 -0700 (PDT) (envelope-from dillon) Date: Thu, 25 Jul 2002 16:26:47 -0700 (PDT) From: Matthew Dillon Message-Id: <200207252326.g6PNQl5F035612@apollo.backplane.com> To: David Schultz Cc: Jaime Bozza , stable@FreeBSD.ORG Subject: Re: RE: Abominable NFSv3 read performance / FreeBSD server / Solaris client References: <200207250002.g6P02m07030238@apollo.backplane.com> <02d401c233e7$49ef80d0$6401010a@bozza> <20020725183646.GA785@HAL9000.homeunix.com> Sender: owner-freebsd-stable@FreeBSD.ORG Precedence: bulk List-ID: List-Archive: (Web Archive) List-Help: (List Instructions) List-Subscribe: List-Unsubscribe: X-Loop: FreeBSD.ORG :... :> setting xmit_hiwat in the startup scripts and restarting the Solaris :> server to assure the setting was changed before the nfs daemons came :> online) I may still not be getting the settings correct, but I'm at a :> loss at what I'm missing. : :Now I'm curious. What is it that makes Solaris<->Solaris :performance good despite the TCP breakage? If the server always :advertises a tiny window, performance ougut to be equally bad when :talking to Solaris or FreeBSD. I've seen threads about this :problem before on the lists, and I don't recall anyone coming up :with a real answer. This could also be due to FreeBSD's lowat/hiwat hysteresis. Again, the real problem here is that the acks being returned by Solaris are running too far behind the data that FreeBSD is sending. Solaris appears to fall back to delayed acks after sending three acks in series, even though it is no where near cleaning up the window, and is making incredibly dumb assumptions as to the hysteresis on the other side of the connection. Solaris itself obviously implements different hysteresis points (if it implements any hysteresis at all). This really does look like a bug in Solaris's delayed-ack implementation to me. -Matt Matthew Dillon To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-stable" in the body of the message