Date: Wed, 21 Apr 1999 23:16:07 -0600 From: Alex Rousskov <rousskov@ircache.net> To: David Greenman <dg@root.com> Cc: freebsd-net@FreeBSD.ORG Subject: Re: _Some_ acks delayed for 200 msec? Message-ID: <Pine.SGI.4.10.9904212307090.6184-100000@Meta-Bug> In-Reply-To: <199904220503.WAA16761@implode.root.com>
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On Wed, 21 Apr 1999, David Greenman wrote: > >Now, if that is the infamous delayed ack problem, then > > - why only *some* acks are delayed? > > Probably because of timing of the response packets. It's impossible to > say with your limited, one-sided tcpdump. Response packets are coming as soon as an ack is sent or prior to that, as far as I can tell. There was a small bi-directional tcpdump in the original post. By "one-sided", do you mean a dump collected on a single [client] host, or that server responses were filtered out in the long dump that I sent? I can certainly provide more info. Just tell me what would be useful. I was afraid of posting long tcpdumps... > The Nagle algorithm doesn't know or care about "local" networks. Right. I confused Nagle with TCP_ACK_HACK (which is sort of a Nagle-like algorithm). TCP_ACK_HACK (a sysctl option in 3.1) does depend on network "locality" from our experience. > > - why disabling Nagle (TCP_NODELAY) does not help? > > It will likely have to be disabled on both sides for your application since > there appears to be a syncronous request/response involved. It was disabled on both sides. Thanks a lot, Alex. To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-net" in the body of the message
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