TCP stack lock contention with short-lived connections
chio1990 at gmail.com
Fri May 30 04:12:28 UTC 2014
Does any plan commit and MFC to the 10-stable ?
于 14-5-29 0:42, Julien Charbon 写道:
> On 23/05/14 22:52, Julien Charbon wrote:
>> On 23/05/14 14:06, Julien Charbon wrote:
>>> On 27/02/14 11:32, Julien Charbon wrote:
>>>> On 07/11/13 14:55, Julien Charbon wrote:
>>>>> On Mon, 04 Nov 2013 22:21:04 +0100, Julien Charbon
>>>>> <jcharbon at verisign.com> wrote:
>>>>>> I have put technical and how-to-repeat details in below PR:
>>>>>> kern/183659: TCP stack lock contention with short-lived connections
>>>>>> We are currently working on this performance improvement
>>>>>> effort; it
>>>>>> will impact only the TCP locking strategy not the TCP stack logic
>>>>>> itself. We will share on freebsd-net the patches we made for
>>>>>> reviewing and improvement propositions; anyway this change might
>>>>>> require enough eyeballs to avoid tricky race conditions introduction
>>>>>> in TCP stack.
>> Joined the two cumulative patches (tcp-scale-inp-list-v1.patch and
>> tcp-scale-pcbinfo-rlock-v1.patch) we discussed the most at BSDCan 2014.
> At BSDCan 2014 we were also asked to provide flame graph  to
> highlight impacts of these TCP changes. The Dtrace sampling was done on
> a NIC receive queue IRQ bound core.
> o First CPU flame graph on 10.0-RELENG at 40k TCP connection/secs:
> - __rw_wlock_hard on ipi_lock contention is clear as usual.
> o Second, same test with all our patches applied (thus from 10.0-next
> branch ):
> - Almost all __rw_wlock_hard on ipi_lock contention is converted in
> idle time.
> o Third, still using 10.0-next branch, the flame graph when doubling
> the rate to 80k TCP connection/sec:
> My 2 cents.
>  http://www.brendangregg.com/FlameGraphs/cpuflamegraphs.html
>  https://wiki.freebsd.org/201405DevSummit/NetworkStack
>  https://github.com/verisign/freebsd/commits/share/10.0-next
> freebsd-net at freebsd.org mailing list
> To unsubscribe, send any mail to "freebsd-net-unsubscribe at freebsd.org"
More information about the freebsd-net