Re: [PATCH] net: tcp: Fix a PTO timing granularity issue

[Eric Dumazet]

On Tue, 2015-05-26 at 13:55 -0400, Ido Yariv wrote:

> 
> The platform this was tested on was an embedded platform with a wifi
> module (11n, 20MHZ). The other end was a computer running Windows, and
> the benchmarking software was IxChariot.
> The whole setup was running in a shielded box with minimal
> interferences.
> 
> As it seems, the throughput was limited by the congestion window.
> Further analysis led to TLP - the fact that its timer was expiring
> prematurely impacted cwnd, which in turn prevented the wireless driver
> from having enough skbs to buffer and send.
> 
> Increasing the size of the chunks being sent had a similar impact on
> throughput, presumably because the congestion window had enough time to
> increase.
> 
> Changing the congestion window to Westwood from cubic/reno also had a
> similar impact on throughput.
> 

Have you tested what results you had by completely disabling TLP ?

Maybe a timer of 10 to 20ms is too short anyway in your testbed.



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