bad NFS/UDP performance

[Jeremy Chadwick]

On Fri, Sep 26, 2008 at 12:27:08PM +0300, Danny Braniss wrote:
> > On Fri, Sep 26, 2008 at 10:04:16AM +0300, Danny Braniss wrote:
> > > Hi,
> > > 	There seems to be some serious degradation in performance.
> > > Under 7.0 I get about 90 MB/s (on write), while, on the same machine
> > > under 7.1 it drops to 20!
> > > Any ideas?
> > 
> > 1) Network card driver changes,
> could be, but at least iperf/tcp is ok - can't get udp numbers, do you
> know of any tool to measure udp performance?
> BTW, I also checked on different hardware, and the badness is there.

According to INDEX, benchmarks/iperf does UDP bandwidth testing.

benchmarks/nttcp should as well.

What network card is in use?  If Intel, what driver version (should be
in dmesg).

> > 2) This could be relevant, but rwatson@ will need to help determine
> >    that.
> >    http://lists.freebsd.org/pipermail/freebsd-stable/2008-September/045109.html
> 
> gut feeling is that it's somewhere else:
> 
> Writing 16 MB file
> 	BS    Count /---- 7.0 ------/ /---- 7.1 -----/
>        1*512  32768 0.16s  98.11MB/s  0.43s 37.18MB/s
>        2*512  16384 0.17s  92.04MB/s  0.46s 34.79MB/s
>        4*512   8192 0.16s 101.88MB/s  0.43s 37.26MB/s
>        8*512   4096 0.16s  99.86MB/s  0.44s 36.41MB/s
>       16*512   2048 0.16s 100.11MB/s  0.50s 32.03MB/s
>       32*512   1024 0.26s  61.71MB/s  0.46s 34.79MB/s
>       64*512    512 0.22s  71.45MB/s  0.45s 35.41MB/s
>      128*512    256 0.21s  77.84MB/s  0.51s 31.34MB/s
>      256*512    128 0.19s  82.47MB/s  0.43s 37.22MB/s
>      512*512     64 0.18s  87.77MB/s  0.49s 32.69MB/s
>     1024*512     32 0.18s  89.24MB/s  0.47s 34.02MB/s
>     2048*512     16 0.17s  91.81MB/s  0.30s 53.41MB/s
>     4096*512      8 0.16s 100.56MB/s  0.42s 38.07MB/s
>     8192*512      4 0.82s  19.56MB/s  0.80s 19.95MB/s
>    16384*512      2 0.82s  19.63MB/s  0.95s 16.80MB/s
>    32768*512      1 0.81s  19.69MB/s  0.96s 16.64MB/s
> 
> Average:                   75.86            33.00
> 
> the nfs filer is a NetWork Appliance, and is in use, so i get fluctuations in 
> the
> measurements, but the relation are similar, good on 7.0, bad on 7.1

Do you have any NFS-related tunings in /etc/rc.conf or /etc/sysctl.conf?

-- 
| Jeremy Chadwick                                jdc at parodius.com |
| Parodius Networking                       http://www.parodius.com/ |
| UNIX Systems Administrator                  Mountain View, CA, USA |
| Making life hard for others since 1977.              PGP: 4BD6C0CB |