Re: hackbench regression due to commit 9dfc6e68bfe6e

[Eric Dumazet]

Le jeudi 08 avril 2010 Ã 00:05 -0700, David Miller a Ãcrit :
> From: Eric Dumazet <eric.dumazet@xxxxxxxxx>
> Date: Thu, 08 Apr 2010 09:00:19 +0200
> 
> > If run individually, the tests results are more what we would expect
> > (slow), but if machine runs the two set of process concurrently, each
> > group runs much faster...
> 
> BTW, I just discovered (thanks to the function graph tracer, woo hoo!)
> that loopback TCP packets get fully checksum validated on receive.
> 
> I'm trying to figure out why skb->ip_summed ends up being
> CHECKSUM_NONE in tcp_v4_rcv() even though it gets set to
> CHECKSUM_PARTIAL in tcp_sendmsg().
> 
> I wonder how much this accounts for some of the hackbench
> oddities... and other regressions in loopback tests we've seen.
> :-)
> 
> Just FYI...

Thanks !

But hackbench is a af_unix benchmark, so loopback stuff is not used that
much :)


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