From: "David S. Miller" <davem@davemloft.net>
To: ak@muc.de
Cc: cndougla@purdue.edu, linux-kernel@vger.kernel.org,
netdev@vger.kernel.org
Subject: Re: TCP prequeue performance
Date: Wed, 15 Jun 2005 16:41:15 -0700 (PDT) [thread overview]
Message-ID: <20050615.164115.74747690.davem@davemloft.net> (raw)
In-Reply-To: <m1br679otj.fsf@muc.de>
From: Andi Kleen <ak@muc.de>
Subject: Re: TCP prequeue performance
Date: Thu, 16 Jun 2005 01:34:48 +0200
> Chase Douglas <cndougla@purdue.edu> writes:
> >
> > I then disabled the prequeue mechanism by changing net/ipv4/tcp.c:1347 of
> > 2.6.11:
> >
> > if (tp->ucopy.task == user_recv) {
> > to
> > if (0 && tp->ucopy.task == user_recv) {
>
> You actually didn't disable it completely - it would still be filled.
Not true, if this check does not pass, tp->ucopy.task is
never set, therefore prequeue processing is never performed.
This test must pass the first time, when both tp->ucopy.task
and user_recv are both NULL, in order for prequeue processing
to occur at all.
So his change did totally disable prequeue.
next prev parent reply other threads:[~2005-06-15 23:41 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <BED5FA3B.2A0%cndougla@purdue.edu>
2005-06-15 20:51 ` TCP prequeue performance David S. Miller
2005-06-15 23:34 ` Andi Kleen
2005-06-15 23:41 ` David S. Miller [this message]
2005-06-16 0:23 ` Andi Kleen
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