Date: Thu, 31 May 2001 13:56:32 -0700 From: David Greenman <dg@root.com> To: Bill Moran <wmoran@iowna.com> Cc: freebsd-questions@freebsd.org Subject: Re: delayed_ack Message-ID: <20010531135632.E25389@nexus.root.com> In-Reply-To: <3B16AFDD.F9167D5D@iowna.com>; from wmoran@iowna.com on Thu, May 31, 2001 at 04:55:57PM -0400 References: <3B16AFDD.F9167D5D@iowna.com>
next in thread | previous in thread | raw e-mail | index | archive | help
>Hi all, > >I'm curious as to some particulars on this sysctl value. >(net.inet.tcp.delayed_ack) I recently found that setting it to 0 >produced a very noticable improvement in the performance of SMB traffic >from windows machine to a Samba server. This machine is 4.2-STABLE >cvsuped on April 5, 12:06. > >I've seen various messages in the mail archives with relation to this >setting and improvements gained. You can add me as one who saw such an >improvement. Specifically, on occasion, transfer operations would pause >(as if waiting for something to happen ... no network activity) and >after 45 seconds, complete. (This is using Windows 95 to connect to the >above described machine) Setting delayed_ack=0 eliminated this delay >completely. > >So ... here is my question: >Is there a problem with the delayed_ack code in FreeBSD? Is it Windows >that is the problem? It seems to me that there's something wrong with >SMB, since HTTP and ssh from Window's boxes works fine. This wasn't a >little performance improvement, this had the feel of something broken >getting fixed. We're talking 45 seconds, with zero network activity, >before the operation completed. > >Not a critical question, mostly curiousity. I think Windows is broken, but SMB should probably set TCP_NODELAY on the socket in any case. Setting delayed_ack=0 will make all TCP connections in the system essentially have the effect of setting TCP_NODELAY on them. -DG David Greenman Co-founder, The FreeBSD Project - http://www.freebsd.org President, TeraSolutions, Inc. - http://www.terasolutions.com Pave the road of life with opportunities. To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-questions" in the body of the message
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?20010531135632.E25389>