Date:	Mon, 28 Jan 2013 07:42:17 +0100
From:	Mike Galbraith <efault@....de>
To:	Alex Shi <alex.shi@...el.com>
Cc:	Borislav Petkov <bp@...en8.de>, torvalds@...ux-foundation.org,
	mingo@...hat.com, peterz@...radead.org, tglx@...utronix.de,
	akpm@...ux-foundation.org, arjan@...ux.intel.com, pjt@...gle.com,
	namhyung@...nel.org, vincent.guittot@...aro.org,
	gregkh@...uxfoundation.org, preeti@...ux.vnet.ibm.com,
	viresh.kumar@...aro.org, linux-kernel@...r.kernel.org
Subject: Re: [patch v4 0/18] sched: simplified fork, release load avg and
 power awareness scheduling

On Mon, 2013-01-28 at 07:15 +0100, Mike Galbraith wrote: 
> On Mon, 2013-01-28 at 13:51 +0800, Alex Shi wrote: 
> > On 01/28/2013 01:17 PM, Mike Galbraith wrote:
> > > On Sun, 2013-01-27 at 16:51 +0100, Mike Galbraith wrote: 
> > >> On Sun, 2013-01-27 at 21:25 +0800, Alex Shi wrote: 
> > >>> On 01/27/2013 06:35 PM, Borislav Petkov wrote:
> > >>>> On Sun, Jan 27, 2013 at 05:36:25AM +0100, Mike Galbraith wrote:
> > >>>>> With aim7 compute on 4 node 40 core box, I see stable throughput
> > >>>>> improvement at tasks = nr_cores and below w. balance and powersaving. 
> > >> ... 
> > >>>> Ok, this is sick. How is balance and powersaving better than perf? Both
> > >>>> have much more jobs per minute than perf; is that because we do pack
> > >>>> much more tasks per cpu with balance and powersaving?
> > >>>
> > >>> Maybe it is due to the lazy balancing on balance/powersaving. You can
> > >>> check the CS times in /proc/pid/status.
> > >>
> > >> Well, it's not wakeup path, limiting entry frequency per waker did zip
> > >> squat nada to any policy throughput.
> > > 
> > > monteverdi:/abuild/mike/:[0]# echo powersaving > /sys/devices/system/cpu/sched_policy/current_sched_policy
> > > monteverdi:/abuild/mike/:[0]# massive_intr 10 60
> > > 043321  00058616
> > > 043313  00058616
> > > 043318  00058968
> > > 043317  00058968
> > > 043316  00059184
> > > 043319  00059192
> > > 043320  00059048
> > > 043314  00059048
> > > 043312  00058176
> > > 043315  00058184
> > > monteverdi:/abuild/mike/:[0]# echo balance > /sys/devices/system/cpu/sched_policy/current_sched_policy
> > > monteverdi:/abuild/mike/:[0]# massive_intr 10 60
> > > 043337  00053448
> > > 043333  00053456
> > > 043338  00052992
> > > 043331  00053448
> > > 043332  00053488
> > > 043335  00053496
> > > 043334  00053480
> > > 043329  00053288
> > > 043336  00053464
> > > 043330  00053496
> > > monteverdi:/abuild/mike/:[0]# echo performance > /sys/devices/system/cpu/sched_policy/current_sched_policy
> > > monteverdi:/abuild/mike/:[0]# massive_intr 10 60
> > > 043348  00052488
> > > 043344  00052488
> > > 043349  00052744
> > > 043343  00052504
> > > 043347  00052504
> > > 043352  00052888
> > > 043345  00052504
> > > 043351  00052496
> > > 043346  00052496
> > > 043350  00052304
> > > monteverdi:/abuild/mike/:[0]#
> > 
> > similar with aim7 results. Thanks, Mike!
> > 
> > Wold you like to collect vmstat info in background?
> > > 
> > > Zzzt.  Wish I could turn turbo thingy off.
> > 
> > Do you mean the turbo mode of cpu frequency? I remember some of machine
> > can disable it in BIOS.
> 
> Yeah, I can do that in my local x3550 box.  I can't fiddle with BIOS
> settings on the remote NUMA box.
> 
> This can't be anything but turbo gizmo mucking up the numbers I think,
> not that the numbers are invalid or anything, better numbers are better
> numbers no matter where/how they come about ;-)
> 
> The massive_intr load is dirt simple sleep/spin with bean counting.  It
> sleeps 1ms spins 8ms.  Change that to sleep 8ms, grind away for 1ms...
> 
> monteverdi:/abuild/mike/:[0]# ./massive_intr 10 60
> 045150  00006484
> 045157  00006427
> 045156  00006401
> 045152  00006428
> 045155  00006372
> 045154  00006370
> 045158  00006453
> 045149  00006372
> 045151  00006371
> 045153  00006371
> monteverdi:/abuild/mike/:[0]# echo balance > /sys/devices/system/cpu/sched_policy/current_sched_policy
> monteverdi:/abuild/mike/:[0]# ./massive_intr 10 60
> 045170  00006380
> 045172  00006374
> 045169  00006376
> 045175  00006376
> 045171  00006334
> 045176  00006380
> 045168  00006374
> 045174  00006334
> 045177  00006375
> 045173  00006376
> monteverdi:/abuild/mike/:[0]# echo performance > /sys/devices/system/cpu/sched_policy/current_sched_policy
> monteverdi:/abuild/mike/:[0]# ./massive_intr 10 60
> 045198  00006408
> 045191  00006408
> 045197  00006408
> 045192  00006411
> 045194  00006409
> 045196  00006409
> 045195  00006336
> 045189  00006336
> 045193  00006411
> 045190  00006410

Back to original 1ms sleep, 8ms work, turning NUMA box into a single
node 10 core box with numactl.

monteverdi:/abuild/mike/:[0]# echo powersaving > /sys/devices/system/cpu/sched_policy/current_sched_policy
monteverdi:/abuild/mike/:[0]# numactl --cpunodebind=0 massive_intr 10 60
045286  00043872
045289  00043464
045284  00043488
045287  00043440
045283  00043416
045281  00044456
045285  00043456
045288  00044312
045280  00043048
045282  00043240
monteverdi:/abuild/mike/:[0]# echo balance > /sys/devices/system/cpu/sched_policy/current_sched_policy
monteverdi:/abuild/mike/:[0]# numactl --cpunodebind=0 massive_intr 10 60
045300  00052536
045307  00052472
045304  00052536
045299  00052536
045305  00052520
045306  00052528
045302  00052528
045303  00052528
045308  00052512
045301  00052520
monteverdi:/abuild/mike/:[0]# echo performance > /sys/devices/system/cpu/sched_policy/current_sched_policy
monteverdi:/abuild/mike/:[0]# numactl --cpunodebind=0 massive_intr 10 60
045339  00052600
045340  00052608
045338  00052600
045337  00052608
045343  00052600
045341  00052600
045336  00052608
045335  00052616
045334  00052576
045342  00052600

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