Hi,
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
<jchar...@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
http://www.freebsd.org/cgi/query-pr.cgi?pr=183659
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 also
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 [1][2] 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:
https://googledrive.com/host/0BwwgoN552srvQi1JWG42TklfQ28/releng10-40k.html
Note:
- __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 [3]):
https://googledrive.com/host/0BwwgoN552srvQi1JWG42TklfQ28/tcp-scale-40k.html
Note:
- 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:
https://googledrive.com/host/0BwwgoN552srvQi1JWG42TklfQ28/tcp-scale-80k.html
My 2 cents.
[1] http://www.brendangregg.com/FlameGraphs/cpuflamegraphs.html
[2] https://wiki.freebsd.org/201405DevSummit/NetworkStack
[3] https://github.com/verisign/freebsd/commits/share/10.0-next
--
Julien
_______________________________________________
freebsd-net@freebsd.org mailing list
http://lists.freebsd.org/mailman/listinfo/freebsd-net
To unsubscribe, send any mail to "freebsd-net-unsubscr...@freebsd.org"
