bad NFS/UDP performance

[Danny Braniss]

> 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.
> 
> 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

Cheers,
	danny