Re: [PATCH] sched,numa: document and fix numa_preferred_nid setting

Srikar Dronamraju
2015-06-22T16:04:57Z

> Would you happen to have 2 instance and 4 instance SPECjbb
> numbers, too? The single instance numbers seem to be within
> the margin of error, but I would expect multi-instance numbers
> to show more dramatic changes, due to changes in how workloads
> converge...
>
> Those behave very differently from single instance, especially
> with the "always set the preferred_nid, even if we moved the
> task to a node we do NOT prefer" patch...
>
> It would be good to understand the behaviour of these patches
> under more circumstances.

Here are specjbb2005 numbers with 1 JVM per System, 2 JVMs per System
and 4 JVMs per System.

Plain 4.1.0-rc7-tip (i)
tip + Rik's ++ (ii)
tip + Srikar's ++ (iii)
tip + Srikar's + Modified Rik's patch (iv)

(i) = Plain 4.1.0-rc7-tip = tip = 4.1.0-rc7 (b7ca96b)

(ii) = tip + only Rik's suggested patches = (i) + Rik's fix numa_preferred_nid setting
+ Srikar's numa hotness + correct nid for evaluating task weight

(iii) = tip + Srikar's ++ (iii) = (i) + Srikar's numa hotness + correct nid for evaluating
task weight + numa_has_capacity fix + always update preferred node

(iv) = tip + Srikar's ++ (iv) = (i) + Srikar's numa hotness + correct nid for evaluating
task weight + numa_has_capacity fix + Rik's modified patch.
(Rik's modified patch == I removed node_isset check before setting
nid as the preferred node)

jbb2005_1JVMperSYSTEM
Plain 4.1.0-rc7-tip (i)
Metric: Min Max Avg StdDev %Change
bopsperJVM: 265519.00 272466.00 269377.80 2391.04

tip + Rik's ++ (ii)
bopsperJVM: 264298.00 271236.00 266818.20 2579.62 -0.94%

tip + Srikar's ++ (iii)
bopsperJVM: 266774.00 272434.00 269839.60 2083.19 0.17%

tip + Srikar's + Rik's (iv)
bopsperJVM: 265037.00 274419.00 269280.00 3146.74 -0.04%

jbb2005_2JVMperSYSTEM
Plain 4.1.0-rc7-tip (i)
Metric: Min Max Avg StdDev %Change
bopsperJVM: 269575.00 288495.00 279910.80 6151.49

tip + Srikar's ++ (iii)
bopsperJVM: 278810.00 287706.00 282514.00 2946.37 0.90%

tip + Rik's ++ (ii)
bopsperJVM: 286785.00 289515.00 288311.80 1206.66 2.90%

tip + Srikar's + Rik's (iv)
bopsperJVM: 283295.00 293466.00 287848.80 3427.06 2.70%

jbb2005_4JVMperSYSTEM
Plain 4.1.0-rc7-tip (i)
Metric: Min Max Avg StdDev %Change
bopsperJVM: 248392.00 263826.00 257263.20 5946.44

tip + Rik's ++ (ii)
bopsperJVM: 257057.00 260303.00 258819.00 1234.46 0.60%

tip + Srikar's ++ (iii)
bopsperJVM: 252968.00 262006.00 257321.80 3131.00 0.02%

tip + Srikar's + Rik's (iv)
bopsperJVM: 257063.00 266196.00 262547.80 3099.57 1.99%

Summary:
While Rik's suggested patchset performs the best in 2 JVM case and
numa01. A modified version of his patch, provides good performance in 2
JVM, 4 JVM cases and numa01. However these two patchsets dont regress in
numa02 (probably a little less with modified patch)

--
Thanks and Regards
Srikar Dronamraju

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