Date: Wed, 18 Mar 2015 18:28:41 -0400 From: Mike Tancsa <mike@sentex.net> To: John-Mark Gurney <jmg@funkthat.com> Cc: FreeBSD-STABLE Mailing List <freebsd-stable@freebsd.org> Subject: Re: 35-40% performance drop releng9 vs releng10 openvpn Message-ID: <5509FC19.2020201@sentex.net> In-Reply-To: <20150318211457.GL51048@funkthat.com> References: <5506250A.2000506@sentex.net> <20150316132055.GQ32288@funkthat.com> <5509D6C6.4050204@sentex.net> <20150318211457.GL51048@funkthat.com>
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On 3/18/2015 5:14 PM, John-Mark Gurney wrote:
>
> So, I would first identify the machine w/ the cpu limited load.. I
> assume that is apu...
Yup, the APU. The machines on either side are significantly faster
> Then I would look at where most of the cpu time
> is being spent, be it openvpn itself, or in the kernel... Most likely
> it is the kernel, so getting stacks from the kernel would be more useful
> than the one you generated... Use the command:
> # 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...
>
Will do, I will work on those.
> As I've never used OpenVPN before and their docs don't go into saying
> what it's using.. Is OpenVPN a kernel or userland VPN? Do they use
> IPSec in the kernel? or are they just using UDP or TCP for their
> connections?
All in userland. I use UDP for the transport, and it uses OpenSSL in
the base for the crypto. In this case, AES-128-CBC. There is no
hardware assist on the APU either to offload the AES.
---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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