Date: Sat, 12 Jul 2014 14:17:32 +0200 From: =?ISO-8859-1?Q?Olivier_Cochard=2DLabb=E9?= <olivier@cochard.me> To: "Bjoern A. Zeeb" <bzeeb-lists@lists.zabbadoz.net> Cc: FreeBSD Net <freebsd-net@freebsd.org>, Navdeep Parhar <nparhar@gmail.com>, John Jasem <jjasen@gmail.com> Subject: Re: tuning routing using cxgbe and T580-CR cards? Message-ID: <CA%2Bq%2BTcpv_UqWCT1z9yimqUYw_TqmQad=8Mirh8VWexMdQ4JGWA@mail.gmail.com> In-Reply-To: <01AABF44-4801-45B5-9509-1CA7BAA3CB30@lists.zabbadoz.net> References: <53C01EB5.6090701@gmail.com> <01AABF44-4801-45B5-9509-1CA7BAA3CB30@lists.zabbadoz.net>
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On Fri, Jul 11, 2014 at 8:03 PM, Bjoern A. Zeeb < bzeeb-lists@lists.zabbadoz.net> wrote: > On 11 Jul 2014, at 17:28 , John Jasem <jjasen@gmail.com> wrote: > > > c) the defaults for the cxgbe driver appear to be 8 rx queues, and N tx > > queues, with N being the number of CPUs detected. For a system running > > multiple cards, routing or firewalling, does this make sense, or would > > balancing tx and rx be more ideal? And would reducing queues per card > > based on NUMBER-CPUS and NUM-CHELSIO-PORTS make sense at all? > > ... > > g) Are there other settings I should be looking at, that may squeeze out > > a few more packets? > > If you are primarily forwarding packets (you say "routing" multiple times) > the first thing you should do is turn off LRO and TSO on all ports. > Hi Bjoern, I was not aware of disabling LRO+TSO for forwarding packet. If I read correctly the wikipedia page of LRO[1]: Disabling LRO is not a concern of performance but only of not breaking the end-to-end principle, right ? But regarding TSO[2]: It should improve performance only between the TCP and IP layer. But paquet forwarded didn't have to cross TCP<->IP layer, then disabling TSO should not impact performance, right ? I've tried to benchs the differences on my lab: - Hardware: quad cores (Intel Xeon L5630 2.13GHz, hyper-threading disabled) with 2 ports Intel 10-Gigabit X540-AT2 - Multi-flows (different UDP ports) of small packet (60B) at about 10Mpps (pkt-gen -f tx -i ix0 -n 1000000000 -l 60 -d 9.3.3.1:2000-9.3.3.1:4000 -D a0:36:9f:1e:28:14 -s 8.3.3.1 -w 4) - Result collected on the receiver side in Paquet-Per-Second unit. ministat -w 74 tso.lro.enabled tso.lro.disabled x tso.lro.enabled + tso.lro.disabled +--------------------------------------------------------------------------+ | + + x+ * x+ x x| ||____________M_|_A________________|________A_M_________________________| | +--------------------------------------------------------------------------+ N Min Max Median Avg Stddev x 5 1724046 1860817 1798145 1793343 61865.164 + 5 1702496 1798998 1725396 1734863.2 38178.905 No difference proven at 95.0% confidence => There is not difference: Then I can disable LRO for respecting the end-to-end principle. But why disabling TSO ? Regards, Olivier [1] http://en.wikipedia.org/wiki/Large_receive_offload [2] http://en.wikipedia.org/wiki/Large_segment_offload
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