OK, I think I found where the RELENG_10 performance loss happened. It seems
https://lists.freebsd.org/pipermail/svn-src-stable-10/2015-March/004778.html
is the issue.
Testing with a kernel from r279796 I get 76-77Mb of throughput. With
r279848 it drops to about 60Mb
---Mike
On 3/20/2015 1:36 PM, Mike Tancsa wrote:
OK, just to refocus,
I had been tracking down what I thought was a regression between RELENG9
and RELENG10, but looks more like an issue that cropped up somewhere
between the beginning of March and now. For RELENG9, I was actually
using a kernel from sources back on Jan 29th by accident. If I bring
RELENG9 upto today, I get a similar performance loss.
Again, I am testing a simple VPN router setup
server1 --- apu --- server2
where server1 connections to the apu via an OpenVPN tunnel and server1
sends packets via netblast across the tunnel to server2.
I get the following throughput using netblast through the tunnel on 10
Using
# netblast 1.1.2.2 500 1200 15 (server1 to server2) on 10.x
Kernel Mb/s
rev
r277684 76.7563
r279978 59.3233
All good at r278533, r278534, r279467
But at r279978 its quite a bit slower. So somewhere between r279467 and
r279978. I will keep trying to narrow it down...
---Mike
On 3/19/2015 8:26 PM, Mike Tancsa wrote:
On 3/18/2015 5:14 PM, John-Mark Gurney wrote:
# dtrace -x stackframes=100 -n 'profile-997 /arg0/ { @[stack()] =
count(); } tick-60s { exit(0); }' -o out.kern_stacks
Also, another thing you can do is to compare the two using differential
flame graphs:
http://www.brendangregg.com/blog/2014-11-09/differential-flame-graphs.html
Which will highlight where the performances differ...
OK, some more data points. It seems a performance regression happened
in RELENG_10 somewhere between r277684 (late January 2015) and now.
Using r277684 on RELENG_10, I can get about 75Mb/s of throughput on
OpenVPN. Still not as good as the 83-85Mb on RELENG_9, but much better
than the 61Mb using RELENG_10 from the start of this week,
For the differential graph, see
http://tancsa.com/diffgraph.svg
and
http://tancsa.com/10-r277684.svg
http://tancsa.com/10-r277684-kern.svg
---Mike
--
-------------------
Mike Tancsa, tel +1 519 651 3400
Sentex Communications, m...@sentex.net
Providing Internet services since 1994 www.sentex.net
Cambridge, Ontario Canada http://www.tancsa.com/
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