Re: Take 2: new IP Checksum Code from DragonFlyBSD

Gordon Bergling wrote:
> Hi,
> 
> a few month ago I ported DragonFlyBSD's IP checksum code to FreeBSD.
> My first try wasn't complete and I had forgotten it by the time. Now I
> hope I have addressed the former mistakes and it maybe included in the
> tree. ;)
> 
> The patch can be found at
> http://generic.0xfce3.net/20060524-ipchecksum.patch
> 
> This patch modifies the i386, amd64 and pc98 architectures. Matt Dillons
> new implementation is machine indepement, but there are some asm
> files/code with seems for me i386 centric. I don't know assembler, so I
> can't tell much about it.
> 
> I applied the patch to RELENG_6 and have done a simple netperf
> benchmark. The machine was a PIII 900.
> 
> The ministat output:
> ----------------------------------------------------------------------------
> x netperf-localhost-plain.txt
> + netperf-localhost-ncksum.txt
> +--------------------------------------------------------------------------+
> |      x     x     x      x        +             ++               +        |
> |xx    x     x  xx xxx    x  x x  x+x   *+x x +  +++   ++  +  + + +++++   +|
> |        |__________M_A____________|        |__________A___________|       |
> +--------------------------------------------------------------------------+
>     N           Min           Max        Median           Avg        Stddev
> x  22        707.31        730.41        717.37     718.53909     6.7389076
> +  22        725.57        746.46       736.535     736.51727     6.3001188
> Difference at 95.0% confidence
> 	17.9782 +/- 3.96904
> 	2.50205% +/- 0.552377%
> 	(Student's t, pooled s = 6.5232)
> ----------------------------------------------------------------------------
> 
> Any comments, correctures are very appreciated.
> 
> best regards,
> 
> 	Gordon
> 

First, it would be nice to know what netstat options you were using. 
Second, it would be nice to know if hardware checksum offloading was
enabled at all on either end of the test.

Scott