On Fri, Aug 21, 2015 at 8:38 PM, Eric Dumazet <[email protected]> wrote: > From: Eric Dumazet <[email protected]> > > When TCP pacing was added back in linux-3.12, we chose > to apply a fixed ratio of 200 % against current rate, > to allow probing for optimal throughput even during > slow start phase, where cwnd can be doubled every other gRTT. > > At Google, we found it was better applying a different ratio > while in Congestion Avoidance phase. > This ratio was set to 120 %. > > We've used the normal tcp_in_slow_start() helper for a while, > then tuned the condition to select the conservative ratio > as soon as cwnd >= ssthresh/2 : > > - After cwnd reduction, it is safer to ramp up more slowly, > as we approach optimal cwnd. > - Initial ramp up (ssthresh == INFINITY) still allows doubling > cwnd every other RTT. > > Signed-off-by: Eric Dumazet <[email protected]> > Cc: Neal Cardwell <[email protected]> > Cc: Yuchung Cheng <[email protected]>
Acked-by: Neal Cardwell <[email protected]> Looks great to me. Thanks, Eric! neal -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
