From: Daniel Jacobowitz <drow@false.org>
To: qemu-devel@nongnu.org
Subject: Re: [Qemu-devel] TCP_NODELAY for -redir
Date: Thu, 16 Nov 2006 21:44:07 -0500 [thread overview]
Message-ID: <20061117024407.GA6559@nevyn.them.org> (raw)
In-Reply-To: <20061113193027.GA2729@nevyn.them.org>
On Mon, Nov 13, 2006 at 02:30:27PM -0500, Daniel Jacobowitz wrote:
> I was trying to run GDB remote debug tests through a -redir socket
> today. It crawled unbelievably. Paul guessed that slirp wasn't using
> TCP_NODELAY, and Nagle was to blame.
>
> He was even righter than usual. Adding TCP_NODELAY speeds up this
> particular workload by (very approximately) 54x. See trivial attached
> patch.
>
> Is this going to bite other things, i.e. does it need to be
> configurable?
No comments on this...
My reasoning, by the way, was that slirp is being used as a TCP-to-TCP
gateway. I think that if we were to use nagle here, we'd end up doing
it twice: once at the sender inside the guest, and once again on the
host's TCP stack. Using TCP_NODELAY lets the guest take
responsibility.
--
Daniel Jacobowitz
CodeSourcery
next prev parent reply other threads:[~2006-11-17 2:44 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2006-11-13 19:30 [Qemu-devel] TCP_NODELAY for -redir Daniel Jacobowitz
2006-11-17 2:44 ` Daniel Jacobowitz [this message]
2006-11-17 14:33 ` [Qemu-devel] PPC Bug Report - Trap Exception setting SRR0 incorrectly Ely Soto
2006-12-19 3:23 ` [Qemu-devel] TCP_NODELAY for -redir Daniel Jacobowitz
-- strict thread matches above, loose matches on Subject: below --
2006-11-17 12:06 Wessel, Jason
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