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Date: Tue, 20 Nov 2012 19:08:09 -0800
From: Alfred Perlstein <bright@mu.org>
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To: Barney Cordoba <barney_cordoba@yahoo.com>
Subject: Re: FreeBSD boxes as a 'router'...
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Cc: freebsd-net@freebsd.org, Ingo Flaschberger <if@xip.at>
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On 11/20/12 3:30 PM, Barney Cordoba wrote:
>
> --- On Tue, 11/20/12, Ingo Flaschberger <if@xip.at> wrote:
>
>> From: Ingo Flaschberger <if@xip.at>
>> Subject: Re: FreeBSD boxes as a 'router'...
>> To: freebsd-net@freebsd.org
>> Date: Tuesday, November 20, 2012, 6:04 PM
>> Am 20.11.2012 23:49, schrieb Alfred
>> Perlstein:
>>> On 11/20/12 2:42 PM, Jim Thompson wrote:
>>>> On Nov 20, 2012, at 3:52 PM, Barney Cordoba <barney_cordoba@yahoo.com>
>> wrote:
>>>> You're entitled to your opinion, but experimental
>> results have tended to show yours incorrect.
>>>> Jim
>>> Agree with Jim.  If you want pure packet
>> performance you burn a core to run a polling loop.
>>
>> At new systems, without polling I had better performance and
>> no live-locks,
>> at old systems (Intel 82541GI) polling prevent live-locks.
>>
>> Best test:
>> Loop a GigE Switch, inject a Packet and plug it into the
>> test-box.
> Yeah, thats a good real-world test.
>
> To me "performance" is not "burning a cpu" to get some extra pps.
> Performance is not dropping buckets of packets. Performance is using
> less cpu to do the same amount of work.
>
> Is a machine that benchmarks at 998Mb/s at 95% cpu really a "higher
> performance" system than one that does 970Mb/s and uses 50% of the cpu?
>
> The measure of performance is to manage an entire load without dropping
> any packets. If your machine goes into live-lock, then you need more
> machine. Hacking it so that it drops packets is hardly a solution.
>
Any free CPU is wasted CPU.  (unless you're concerned about power 
consumption, then it's debatable).

-Alfred