What's the status of parallel netisr?

Kris Kennaway kris at FreeBSD.org
Sun Sep 21 09:57:48 UTC 2008


Jian Qiu wrote:
> Hi, Kris,
> 
>> In our application-level tests FreeBSD significantly out-performs Linux, so
>> either you have found a different workload, or something is not configured
>> equally.  One important thing I can think of off the top of my head is that
>> Linux has a larger socket buffer size by default, so try tuning that on
>> FreeBSD or confirm they are equal.
>>
>> If that still fails, can you provide test code?
>>
>> Kris
>>
> 
> I tried but larger socket buffer seem not helpful.
> 
> I also tried netperf and iperf. Both applications achieve better
> throughput on Linux.
> 
> So I feel the result is not specific to my test code.
> 
> My code is very simple. Basically, a client process called sendto in a
> loop while a server called recvfrom in a loop.
> Besides these, some additional lines get the throughput statistics. If
> necessary, I will post the code here.
> 
> BTW, I did the tests on Linux 2.26.5. Which linux kernel did you use?
> 
> Could you please provide some more information on your test.

The ones I have in mind were application level benchmarks of things like 
DNS and memcached.  I tested on 2.6.25, which is perhaps what you meant 
to say too.

Try to keep looking for other factors that might still be in play, like 
hardware or driver differences.

Kris



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