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

[Rob Ross]

Nice Scott! What's the realistic BW limit for this hardware?

Rob

Scott Atchley wrote:
> On Jan 5, 2007, at 11:47 AM, Scott Atchley wrote:
> 
>> 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
> 
> The above was with 1 MB buffers. With 16 MB buffers:
> 
> % mpiexec -n 1  ./perf -fname pvfs2:/mnt/pvfs2/x1
> Access size per process = 268435456 bytes, ntimes = 10
> Write bandwidth without file sync = 822.867597 Mbytes/sec
> Read bandwidth without prior file sync = 844.154572 Mbytes/sec
> Write bandwidth including file sync = 823.773517 Mbytes/sec
> Read bandwidth after file sync = 844.393557 Mbytes/sec
> 
> With 4 MB buffers:
> 
> % mpiexec -n 1  ./perf -fname pvfs2:/mnt/pvfs2/x1
> Access size per process = 268435456 bytes, ntimes = 10
> Write bandwidth without file sync = 847.215804 Mbytes/sec
> Read bandwidth without prior file sync = 862.068630 Mbytes/sec
> Write bandwidth including file sync = 847.861378 Mbytes/sec
> Read bandwidth after file sync = 862.307479 Mbytes/sec
> 
> The client CPU usage was 25% for both values. I do not see any benefit 
> for larger than 1 MB buffers.
> 
> Scott
> 
> 
> 
> _______________________________________________
> Pvfs2-developers mailing list
> Pvfs2-developers at beowulf-underground.org
> http://www.beowulf-underground.org/mailman/listinfo/pvfs2-developers
>