Re: [Lse-tech] Re: [patch] sched-2.5.59-A2

Michael Hohnbaum
2003-01-18T00:02:21Z

On Fri, 2003-01-17 at 11:26, Martin J. Bligh wrote:
>
> System times are little higher (multipliers are set at busy = 10,
> idle = 10) .... I'll try setting the idle multipler to 100, but
> the other thing to do would be into increase the cross-node migrate
> resistance by setting some minimum imbalance offsets. That'll
> probably have to be node-specific ... something like the number
> of cpus per node ... but probably 0 for the simple HT systems.
>
> M.

I tried several values for the multipliers (IDLE_NODE_REBALANCE_TICK
and BUSY_NODE_REBALANCE_TICK) on a 4 node NUMAQ (16 700MHZ Pentium III
CPUs, 16 GB memory). The interesting results follow:

Kernels:

stock59 - linux 2.5.59 with cputime_stats patch
ingoI50B10 - stock59 with Ingo's B0 patch as modified by Martin
with a IDLE_NODE_REBALANCE_TICK multiplier of 50
and a BUSY_NODE_REBALANCE_TICK multiplier of 10
ingoI2B2 - stock59 with Ingos B0 patch with the original multipliers (2)

Kernbench:
Elapsed User System CPU
ingoI50B10 29.574s 284.922s 84.542s 1249%
stock59 29.498s 283.976s 83.05s 1243.8%
ingoI2B2 30.212s 289.718s 84.926s 1240%

Schedbench 4:
AvgUser Elapsed TotalUser TotalSys
ingoI50B10 22.49 37.04 90.00 0.86
stock59 22.25 35.94 89.06 0.81
ingoI2B2 24.98 40.71 99.98 1.03

Schedbench 8:
AvgUser Elapsed TotalUser TotalSys
ingoI50B10 31.16 49.63 249.32 1.86
stock59 28.40 42.25 227.26 1.67
ingoI2B2 36.81 59.38 294.57 2.02

Schedbench 16:
AvgUser Elapsed TotalUser TotalSys
ingoI50B10 52.73 56.61 843.91 3.56
stock59 52.97 57.19 847.70 3.29
ingoI2B2 57.88 71.32 926.29 5.51

Schedbench 32:
AvgUser Elapsed TotalUser TotalSys
ingoI50B10 58.85 139.76 1883.59 8.07
stock59 56.57 118.05 1810.53 5.97
ingoI2B2 61.48 137.38 1967.52 10.92

Schedbench 64:
AvgUser Elapsed TotalUser TotalSys
ingoI50B10 70.74 297.25 4528.25 19.09
stock59 56.75 234.12 3632.72 15.70
ingoI2B2 70.56 298.45 4516.67 21.41

Martin already posted numbers with 10/10 for the multipliers.

It looks like on the NUMAQ the 50/10 values give the best results,
at least on these tests. I suspect that on other architectures
the optimum numbers will vary. Most likely on machines with lower
latency to off node memory, lower multipliers will help. It will
be interesting to see numbers from Erich from the NEC IA64 boxes.
--

Michael Hohnbaum 503-578-5486
hohnbaum@us.ibm.com T/L 775-5486