Messages in this thread | | | Subject | Re: [Xen-devel] "tcp: refine TSO autosizing" causes performance regression on Xen | From | Eric Dumazet <> | Date | Wed, 15 Apr 2015 10:41:28 -0700 |
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On Wed, 2015-04-15 at 18:23 +0100, George Dunlap wrote:
> Which means that max(2*skb->truesize, sk->sk_pacing_rate >>10) is > *already* larger for Xen; that calculation mentioned in the comment is > *already* doing the right thing.
Sigh.
1ms of traffic at 40Gbit is 5 MBytes
The reason for the cap to /proc/sys/net/ipv4/tcp_limit_output_bytes is to provide the limitation of ~2 TSO packets, which _also_ is documented.
Without this limitation, 5 MBytes could translate to : Fill the queue, do not limit.
If a particular driver needs to extend the limit, fine, document it and take actions.
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