Re: poor OSD performance using kernel 3.4

[Stefan Priebe - Profihost AG <s.priebe@profihost.ag>]

Even with v3.3-rc1 is pretty often 0.

Am 25.05.2012 13:31, schrieb Stefan Priebe - Profihost AG:
> 
> Some speed tests with different Kernel Versions. The same applies to
> other FS like btrfs.
> I used "rados -p data bench 100 write -t 16" for all tests and a freshly
> created FS. mount options were always: noatime,nodiratime,nobarrier.
> 
> 3.0.30 with XFS
> 
> speed is always between 120 and 160MB/s
> 
> Total time run:        100.510061
> Total writes made:     3605
> Write size:            4194304
> Bandwidth (MB/sec):    143.468
> 
> Average Latency:       0.445714
> Max latency:           1.99929
> Min latency:           0.084812
> 
> 3.2.18 with XFS
> 
> speed is between 40 and 170MB/s
> 
> Total time run:        100.795653
> Total writes made:     3384
> Write size:            4194304
> Bandwidth (MB/sec):    134.292
> 
> Average Latency:       0.476297
> Max latency:           2.92075
> Min latency:           0.084884
> 
> 3.3.7 with XFS
> 
> !! speed heavily jumps between 0 and 170 MB/s !!
> 
> Total time run:        107.398166
> Total writes made:     2455
> Write size:            4194304
> Bandwidth (MB/sec):    91.435
> 
> Average Latency:       0.699819
> Max latency:           13.8117
> Min latency:           0.084624
> 
> 3.4 with XFS
> 
> !! speed heavily jumps between 0 and 130 MB/s - most if the time it's
> near 0 !!
> 
> Total time run:        115.433531
> Total writes made:     468
> Write size:            4194304
> Bandwidth (MB/sec):    16.217
> 
> Average Latency:       3.9452
> Max latency:           53.4356
> Min latency:           0.091276
> 
> 
> Stefan