Subject: Re: TCP prequeue performance

From: Andi Kleen <[email-masked]>
Date: Thu, 16 Jun 2005 02:23:59 +0200

"David S. Miller" <[email-masked]> writes:
>
> Not true, if this check does not pass, tp->ucopy.task is
> never set, therefore prequeue processing is never performed.

Oh well, here goes my nice theory :)
>
> 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.

Then probably his test was latency bound somehow, but normally
that should not affect system time, just wall time.

I would perhaps compare context switch numbers and netstat -s
output between the different runs and see if anything pops out.

-Andi