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Date:      Mon, 8 Aug 2016 15:52:16 +0200
From:      Ben RUBSON <ben.rubson@gmail.com>
To:        freebsd-net <freebsd-net@freebsd.org>
Subject:   Re: Unstable local network throughput
Message-ID:  <647B1F5C-EF03-4DC5-B5AC-75AD1995A20B@gmail.com>
In-Reply-To: <bc872304-aac7-2b21-2f83-7aea3cc82386@selasky.org>
References:  <3C0D892F-2BE8-4650-B9FC-93C8EE0443E1@gmail.com> <bed13ae3-0b8f-b1af-7418-7bf1b9fc74bc@selasky.org> <3B164B7B-CBFB-4518-B57D-A96EABB71647@gmail.com> <5D6DF8EA-D9AA-4617-8561-2D7E22A738C3@gmail.com> <06E414D5-9CDA-46D1-A26F-0B07E76FDB34@gmail.com> <0b14bf39-ed71-b9fb-1998-bd9676466df6@selasky.org> <E5BE8DAC-AB6A-491E-A901-4E513367278B@gmail.com> <CAFMmRNz8WryZVVR-_OvB7Ad3tR1NqPpXpv_QEPkoffxdFzdUQw@mail.gmail.com> <A5742F79-C2C2-4040-A369-D8CFE6B48D33@gmail.com> <bc872304-aac7-2b21-2f83-7aea3cc82386@selasky.org>

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> On 05 Aug 2016, at 10:30, Hans Petter Selasky <hps@selasky.org> wrote:
>=20
> On 08/04/16 23:49, Ben RUBSON wrote:
>>>=20
>>> On 04 Aug 2016, at 20:15, Ryan Stone <rysto32@gmail.com> wrote:
>>>=20
>>> On Thu, Aug 4, 2016 at 11:33 AM, Ben RUBSON <ben.rubson@gmail.com> =
wrote:
>>> But even without RSS, I should be able to go up to 2x40Gbps, don't =
you think so ?
>>> Nobody already did this ?
>>>=20
>>> Try this patch
>>> (...)
>>=20
>> I also just tested the NODEBUG kernel but it did not help.
>=20
> Hi,
>=20
> When running these tests, do you see any CPUs fully utilised?

No, CPUs look like this on both servers :

27 processes:  1 running, 26 sleeping
CPU 0:   1.1% user,  0.0% nice, 16.7% system,  0.0% interrupt, 82.2% =
idle
CPU 1:   1.1% user,  0.0% nice, 18.9% system,  0.0% interrupt, 80.0% =
idle
CPU 2:   1.9% user,  0.0% nice, 17.8% system,  0.0% interrupt, 80.4% =
idle
CPU 3:   1.1% user,  0.0% nice, 15.2% system,  0.0% interrupt, 83.7% =
idle
CPU 4:   0.4% user,  0.0% nice, 16.3% system,  0.0% interrupt, 83.3% =
idle
CPU 5:   1.1% user,  0.0% nice, 14.4% system,  0.0% interrupt, 84.4% =
idle
CPU 6:   2.6% user,  0.0% nice, 17.4% system,  0.0% interrupt, 80.0% =
idle
CPU 7:   2.2% user,  0.0% nice, 15.2% system,  0.0% interrupt, 82.6% =
idle
CPU 8:   1.1% user,  0.0% nice,  3.0% system, 15.9% interrupt, 80.0% =
idle
CPU 9:   0.0% user,  0.0% nice,  3.0% system, 32.2% interrupt, 64.8% =
idle
CPU 10:  0.0% user,  0.0% nice,  0.4% system, 58.9% interrupt, 40.7% =
idle
CPU 11:  0.0% user,  0.0% nice,  0.4% system, 77.4% interrupt, 22.2% =
idle
CPU 12:  0.0% user,  0.0% nice,  0.0% system,  0.0% interrupt,  100% =
idle
CPU 13:  0.0% user,  0.0% nice,  0.0% system,  0.0% interrupt,  100% =
idle
CPU 14:  0.0% user,  0.0% nice,  0.0% system,  0.0% interrupt,  100% =
idle
CPU 15:  0.0% user,  0.0% nice,  0.0% system,  0.0% interrupt,  100% =
idle
CPU 16:  0.0% user,  0.0% nice,  0.0% system,  0.0% interrupt,  100% =
idle
CPU 17:  0.0% user,  0.0% nice,  0.0% system,  0.0% interrupt,  100% =
idle
CPU 18:  0.0% user,  0.0% nice,  0.0% system,  0.0% interrupt,  100% =
idle
CPU 19:  0.0% user,  0.0% nice,  0.0% system,  0.0% interrupt,  100% =
idle
CPU 20:  0.0% user,  0.0% nice,  0.0% system,  0.0% interrupt,  100% =
idle
CPU 21:  0.0% user,  0.0% nice,  0.0% system,  0.4% interrupt, 99.6% =
idle
CPU 22:  0.0% user,  0.0% nice,  0.0% system,  0.0% interrupt,  100% =
idle
CPU 23:  0.0% user,  0.0% nice,  0.0% system,  0.0% interrupt,  100% =
idle

Load is correctly spread over the NUMA connected to the NIC (the first =
12 CPUs).
There is clearly enough power to fulfill the full-duplex link !
I tried many cpuset configurations (IRQs over the 12 CPUs etc...), but =
no improvement at all.

> Did you check the RX/TX pauseframes settings and the mlx4 sysctl =
statistics counters, if there is packet loss?

I tried to disable RX/TX pauseframes, but it did not help.
And "sysctl -a | grep mlx | grep err" counters are all 0.
I also played with ring size, adaptive interrupt moderation... with no =
luck.

Ben




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