On Tue, 2013-04-30 at 10:41 +0200, Ingo Molnar wrote:
> * Mike Galbraith <[email protected]> wrote:
>
> > On Tue, 2013-04-30 at 07:16 +0200, Mike Galbraith wrote:
> >
> > > Well now, that's not exactly what I expected to see for AIM7 compute.
> > > Filesystem is munching cycles otherwise used for compute when load is
> > > spread across the whole box vs consolidated.
> >
> > So AIM7 compute performance delta boils down to: powersaving stacks
> > tasks, so they pat single bit of spinning rust sequentially/gently.
>
> So AIM7 with real block IO improved, due to sequentiality. Does it improve
> if AIM7 works on an SSD, or into ramdisk?
Seriously doubt it, but I suppose I can try tmpfs.
performance
Tasks jobs/min jti jobs/min/task real cpu
20 11170.51 99 558.5253 10.85 15.19 Tue Apr 30 11:21:46
2013
20 11078.61 99 553.9305 10.94 15.59 Tue Apr 30 11:21:57
2013
20 11191.14 99 559.5568 10.83 15.29 Tue Apr 30 11:22:08
2013
powersaving
Tasks jobs/min jti jobs/min/task real cpu
20 10978.26 99 548.9130 11.04 19.25 Tue Apr 30 11:22:38
2013
20 10988.21 99 549.4107 11.03 18.71 Tue Apr 30 11:22:49
2013
20 11008.17 99 550.4087 11.01 18.85 Tue Apr 30 11:23:00
2013
Nope.
> Which are the workloads where 'powersaving' mode hurts workload
> performance measurably?
Well, it'll lose throughput any time there's parallel execution
potential but it's serialized instead.. using average will inevitably
stack tasks sometimes, but that's its goal. Hackbench shows it.
performance
monteverdi:/abuild/mike/aim7/:[0]# hackbench -l 1000
Running in process mode with 10 groups using 40 file descriptors each (== 400
tasks)
Each sender will pass 1000 messages of 100 bytes
Time: 0.487
monteverdi:/abuild/mike/aim7/:[0]# hackbench -l 1000
Running in process mode with 10 groups using 40 file descriptors each (== 400
tasks)
Each sender will pass 1000 messages of 100 bytes
Time: 0.487
monteverdi:/abuild/mike/aim7/:[0]# hackbench -l 1000
Running in process mode with 10 groups using 40 file descriptors each (== 400
tasks)
Each sender will pass 1000 messages of 100 bytes
Time: 0.497
powersaving
monteverdi:/abuild/mike/aim7/:[0]# hackbench -l 1000
Running in process mode with 10 groups using 40 file descriptors each (== 400
tasks)
Each sender will pass 1000 messages of 100 bytes
Time: 0.702
monteverdi:/abuild/mike/aim7/:[0]# hackbench -l 1000
Running in process mode with 10 groups using 40 file descriptors each (== 400
tasks)
Each sender will pass 1000 messages of 100 bytes
Time: 0.679
monteverdi:/abuild/mike/aim7/:[0]# hackbench -l 1000
Running in process mode with 10 groups using 40 file descriptors each (== 400
tasks)
Each sender will pass 1000 messages of 100 bytes
Time: 1.137
-Mike
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