Re: NUMA scheduler (was: 2.5 merge candidate list 1.5)

Martin J. Bligh (mbligh@aracnet.com)
Sun, 27 Oct 2002 10:16:58 -0800


> OK, I went to your latest patches (just 1 and 2). And they worked!
> You've fixed the performance degradation problems for kernel compile
> (now a 14% improvement in systime), that core set works without
> further futzing about or crashing, with or without TSC, on either
> version of gcc ... congrats!

So I have a slight correction to make to the above ;-) Your patches
do work just fine, no crashes any more. HOWEVER ... turns out I only
had the first patch installed, not both. Silly mistake, but turns out
to be very interesting.

So your second patch is the balance on exec stuff ... I've looked at
it, and think it's going to be very expensive to do in practice, at
least the simplistic "recalc everything on every exec" approach. It
does benefit the low end schedbench results, but not the high end ones,
and you can see the cost of your second patch in the system times of
the kernbench.

In summary, I think I like the first patch alone better than the
combination, but will have a play at making a cross between the two.
As I have very little context about the scheduler, would appreciate
any help anyone would like to volunteer ;-)

Corrected results are:

Kernbench:
Elapsed User System CPU
2.5.44-mm4 19.676s 192.794s 42.678s 1197.4%
2.5.44-mm4-hbaum 19.422s 189.828s 40.204s 1196.2%
2.5.44-mm4-focht-1 19.46s 189.838s 37.938s 1171%
2.5.44-mm4-focht-12 20.32s 190s 44.4s 1153.6%

Schedbench 4:
Elapsed TotalUser TotalSys AvgUser
2.5.44-mm4 32.45 49.47 129.86 0.82
2.5.44-mm4-hbaum 31.31 43.85 125.29 0.84
2.5.44-mm4-focht-1 38.61 45.15 154.48 1.06
2.5.44-mm4-focht-12 23.23 38.87 92.99 0.85

Schedbench 8:
Elapsed TotalUser TotalSys AvgUser
2.5.44-mm4 39.90 61.48 319.26 2.79
2.5.44-mm4-hbaum 32.63 46.56 261.10 1.99
2.5.44-mm4-focht-1 37.76 61.09 302.17 2.55
2.5.44-mm4-focht-12 28.40 34.43 227.25 2.09

Schedbench 16:
Elapsed TotalUser TotalSys AvgUser
2.5.44-mm4 62.99 93.59 1008.01 5.11
2.5.44-mm4-hbaum 49.78 76.71 796.68 4.43
2.5.44-mm4-focht-1 51.69 60.23 827.20 4.95
2.5.44-mm4-focht-12 51.24 60.86 820.08 4.23

Schedbench 32:
Elapsed TotalUser TotalSys AvgUser
2.5.44-mm4 88.13 194.53 2820.54 11.52
2.5.44-mm4-hbaum 54.67 147.30 1749.77 7.91
2.5.44-mm4-focht-1 56.71 123.62 1815.12 7.92
2.5.44-mm4-focht-12 55.69 118.85 1782.25 7.28

Schedbench 64:
Elapsed TotalUser TotalSys AvgUser
2.5.44-mm4 159.92 653.79 10235.93 25.16
2.5.44-mm4-hbaum 65.20 300.58 4173.26 16.82
2.5.44-mm4-focht-1 55.60 232.36 3558.98 17.61
2.5.44-mm4-focht-12 56.03 234.45 3586.46 15.76

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