Messages in this thread |  | | Subject | Re: "tcp: refine TSO autosizing" causes performance regression on Xen | From | Eric Dumazet <> | Date | Thu, 09 Apr 2015 10:07:05 -0700 |
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On Thu, 2015-04-09 at 17:36 +0100, Stefano Stabellini wrote:
> A very big difference: > > echo 262144 > /proc/sys/net/ipv4/tcp_limit_output_bytes > brings us much closer to the original performance, the slowdown is just > 8%
Cool.
> > echo 1048576 > /proc/sys/net/ipv4/tcp_limit_output_bytes > fills the gap entirely, same performance as before "refine TSO > autosizing"
Sure, this basically disables TCP Small Queue and select the opposite :
Favor single flow throughput and huge latencies (bufferbloat)
> > > What would be the next step for here? Should I just document this as an > important performance tweaking step for Xen, or is there something else > we can do?
I guess this is a reasonable choice.
Note that /proc/sys/net/ipv4/tcp_limit_output_bytes is already documented.
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