gettimeofday() in hping

Kris Kennaway kris at FreeBSD.org
Mon Feb 4 02:55:01 PST 2008


Stefan Lambrev wrote:
> Greetings,
> 
> Kris Kennaway wrote:
>> Kris Kennaway wrote:
>>
>>>> Fixing all of the above I can send at about 13MB/sec (timecounter is 
>>>> not relevant any more).  The CPU is spending about 75% of the time 
>>>> in the kernel, so
>>>              that is the next place to look. [hit send too soon]
>>
>> Actually 15MB/sec once I disable all kernel debugging.  This is 
>> identical to Linux 2.6.24 on the same hardware.  The patch I use to 
>> fix hping brain-damage is attached.
>>
>> Kris
> Indeed this patch highly improve results (x2) under FreeBSD. On my 
> hardware the max speeds under FreeBSD i still little slower compared to 
> Linux (something like 19 vs 19.5 MB/s)
> but the speed is quite more stable under FreeBSD (under linux the 
> average speed seems slower)
> 
> I didn't tested the patch under linux but will do soon.
> Thanks for the help :)
> 
> BTW 262144 is little high as this match the default value in FreeBSD, I 
> tested with twice smaller buffer and do not see performance lost.
> Kris if you do not mind I'll write to hping developers to adopt this 
> patch, and if no response from them I can try to reach the port 
> maintainer, so we have this patched in ports?
> 

My patch is a bit crude, because I didnt have the courage to digest the 
entire structure of the code, so it may be slightly wrong with respect 
to other operating modes (the #if 0 part is wrong, but that code needs 
to be rewritten). Some version of it should be included in the software, 
but perhaps after renaming the patch file ;-)

Kris


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