Re: [PATCH] tcp: disable auto corking by default

[Eric Dumazet]

On Sat, 2014-02-08 at 17:55 +0100, Thomas Glanzmann wrote:
> Hello Eric,
> 
> > > Disable auto corking by default
> 
> > We should let auto corking on during 3.14 development cycle so that we
> > can fix the bugs, and thing of some optimizations.
> 
> I agree that leaving it enabled helps to find bugs, however I'm not
> happy with the round trip time degradation.
> 
> > auto cork gives a strong incentive to applications to use
> > TCP_CORK/MSG_MORE to avoid overhead of sending multiple small
> > segments.
> 
> I agree. But if it breaks the application many people won't be happy,
> for example I spend already 5 hours to track it down.

Sure, but if we put this flag to zero, nobody will ever use it and find
any bug.

Thanks for running latest git tree and be part of linux improvement.

If we can add the MSG_MORE at the right place, your workload might gain
~20% exec time, and maybe 30% better efficiency, since you'll divide by
2 the total number of network segments.

Just to be clear : No stable kernel has yet any issue, right ?



--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/