[linux-cifs-client] Re: debugging dbench to track performance

Jeremy Allison jra at samba.org
Sat Jul 15 19:54:23 GMT 2006


On Sat, Jul 15, 2006 at 01:04:44PM -0500, Steve French wrote:
> Running with very current cifs against very current SAMBA_3 branch 
> (server) - cifs mount over loopback interface
> 
> I am getting puzzling behavior of dbench again - with "dbench 70" (ie 70 
> processes) dbench never gets out of warmup mode (my guess is that a 
> request or two gets lost on the server or is so slow that dbench thinks 
> that it has not reached steady state for warmup - but I am not I am 
> convinced that I understand dbench's warmup phase properly).   Running 
> it with fewer processes dbench gets through its warmup fine but is 
> performing pretty poorly (hopefully because of the memory leak in Samba 
> that jra mentioned - but I am not convinced that that is the issue).   
> Also note that "cannot remove directory" errors in the cleanup phase - 
> any ideas how to debug those (there is presumably too much data to catch 
> this on a sniffer without affecting timing) ie catch the problem earlier 

With the latest SAMBA_3_0 server code and the modified cifsfs I
can complete a dbench 70 very quickly. Here's the output.

jeremy at linux:/mnt> dbench 70
70 clients started
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++**********************************************************************
Throughput 146.972 MB/sec (NB=183.715 MB/sec  1469.72 MBit/sec)  70 procs

I'm not getting any errors (on the command line or in /var/log/messages).

Here's a timed version :

jeremy at linux:/mnt> time dbench 70
70 clients started
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++**********************************************************************
Throughput 305.796 MB/sec (NB=382.245 MB/sec  3057.96 MBit/sec)  70 procs

real    0m30.230s
user    1m57.136s
sys     0m1.794s

Does that look reasonable ? (Not run dbench much before...). This is
with dbench 3.04.

Jeremy.


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