Date: Fri, 20 Mar 2015 17:02:38 -0400 From: Mike Tancsa <mike@sentex.net> To: John-Mark Gurney <jmg@funkthat.com> Cc: FreeBSD-STABLE Mailing List <freebsd-stable@freebsd.org>, John Baldwin <jhb@freebsd.org> Subject: Re: RELENG_10 performance regression (was Re: 35-40% performance drop releng9 vs releng10 openvpn Message-ID: <550C8AEE.4090408@sentex.net> In-Reply-To: <550C5AAF.9060502@sentex.net> References: <5506250A.2000506@sentex.net> <20150316132055.GQ32288@funkthat.com> <5509D6C6.4050204@sentex.net> <20150318211457.GL51048@funkthat.com> <550B6950.8060806@sentex.net> <550C5AAF.9060502@sentex.net>
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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, mike@sentex.net Providing Internet services since 1994 www.sentex.net Cambridge, Ontario Canada http://www.tancsa.com/
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