[Pvfs2-developers] pvfs2-cp performance with single client and single server

[Scott Atchley]

On Jan 5, 2007, at 11:38 AM, Scott Atchley wrote:

> On Dec 29, 2006, at 11:44 AM, Pete Wyckoff wrote:
>
>> pvfs2-cp isn't that great a code.  Find yourself an MPI interface
>> benchmark, like "perf".  This produces server load around 90%:
>>
>> ib30$ mpiexec -n 1 2402/perf -n 10 -s 800m -c 100m -f pvfs2:/pvfs- 
>> ib/x1
>> #np size   chunk  write no sync- read no sync-- write sync----  
>> read sync-----
>> #   (MB)    (MB)  (MB/s)         (MB/s)         (MB/s)         (MB/s)
>> 1    800.0  100.0 681.56 +-  1.9 612.87 +-  2.2 679.99 +-  1.0  
>> 613.76 +-  3.0
>>
>> With 1 MB flow buffers, the server is pegged and slower, more like
>> what you're seeing:
>>
>> ib30$ mpiexec -n 1 2402/perf -n 10 -s 800m -c 100m -f pvfs2:/pvfs- 
>> ib/x1
>> #np size   chunk  write no sync- read no sync-- write sync----  
>> read sync-----
>> #   (MB)    (MB)  (MB/s)         (MB/s)         (MB/s)         (MB/s)
>> 1    800.0  100.0 342.73 +-  3.8 317.24 +-  2.6 343.96 +-  2.2  
>> 318.34 +-  1.8

I modified perf.c to write 10 times a buffer of 128 MBs. I get:

% mpiexec -n 1  ./perf -fname pvfs2:/mnt/pvfs2/x1
Access size per process = 134217728 bytes, ntimes = 10
Write bandwidth without file sync = 827.824860 Mbytes/sec
Read bandwidth without prior file sync = 870.979531 Mbytes/sec
Write bandwidth including file sync = 827.166730 Mbytes/sec
Read bandwidth after file sync = 865.624838 Mbytes/sec

using a single client. The client used about 25% CPU.

Scott