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From: Andrew Grover <andy.grover@gmail.com>
To: netdev@oss.sgi.com
Subject: prequeue still a good idea?
Date: Thu, 28 Apr 2005 11:49:32 -0700	[thread overview]
Message-ID: <c0a09e5c05042811492162746@mail.gmail.com> (raw)

I came across this comment from include/net/tcp.h tcp_prequeue:

/* Packet is added to VJ-style prequeue for processing in process
 * context, if a reader task is waiting. Apparently, this exciting
 * idea (VJ's mail "Re: query about TCP header on tcp-ip" of 07 Sep 93)
 * failed somewhere. Latency? Burstiness? Well, at least now we will
 * see, why it failed. 8)8)				  --ANK
 */

I'm trying to understand -- is the prequeue really not a win, and if
so, why do we still have it?

Especially with modern tcp csumming HW, its benefit is not clear to
me. The whole point of the prequeue, and calling tcp_v4_do_rcv from
user context, was to speed up *sw* csum, right?

Thanks -- Regards -- Andy

             reply	other threads:[~2005-04-28 18:49 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2005-04-28 18:49 Andrew Grover [this message]
2005-04-28 18:52 ` prequeue still a good idea? David S. Miller

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