Re: [announce] CFS-devel, performance improvements

Rob Hussey
2007-09-14T01:47:45Z

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On 9/13/07, Ingo Molnar <mingo@elte.hu> wrote:
>
> * Rob Hussey <robjhussey@gmail.com> wrote:
>
> > Well, I was going over my config myself after you asked for me to post
> > it, and I thought to do the same thing. Except, disabling sched_debug
> > caused the same error as before:
> > In file included from kernel/sched.c:794:
> > kernel/sched_fair.c: In function 'task_new_fair':
> > kernel/sched_fair.c:857: error: 'sysctl_sched_child_runs_first'
> > undeclared (first use in this function)
> > kernel/sched_fair.c:857: error: (Each undeclared identifier is
> > reported only once
> > kernel/sched_fair.c:857: error: for each function it appears in.)
> > make[1]: *** [kernel/sched.o] Error 1
> > make: *** [kernel] Error 2
> >
> > It only happens with sched_debug=y. I take it back, it wasn't my fault :)
> >
> > As for everything else, I'd be happy to.
>
> are you sure this is happening with the latest iteration of the patch
> too? (with the combo-3.patch?) You can pick it up from here:
>
> http://people.redhat.com/mingo/cfs-scheduler/devel/sched-cfs-v2.6.23-rc6-v21-combo-3.patch
>
> I tried your config and it builds fine here.
>
> Ingo
>

I managed to work it all out (it was my fault after all), and I've now
made the changes you suggested to my .configs for 2.6.23-rc1 and
2.6.23-rc6. I've done the benchmarks all over, including tests with
the task bound to a single core. Without further ado, the numbers I
promised:

lat_ctx -s 0 2
# rc1 rc6 cfs-devel
1 4.58 4.39 4.42
2 4.76 4.42 4.41
3 4.74 4.52 4.67
4 4.74 4.44 4.76
5 4.79 4.74 4.59
6 4.80 4.65 4.76
7 4.52 4.54 4.50
8 4.72 4.57 4.62
9 4.87 4.67 4.80
10 4.69 4.47 4.65

hackbench 50
# rc1 rc6 cfs-devel
1 6.634 5.969 5.894
2 6.342 5.974 5.903
3 6.219 5.913 5.941
4 6.702 5.980 5.916
5 6.287 6.007 5.943
6 6.239 6.022 5.899
7 6.434 5.946 5.904
8 6.229 6.007 5.941
9 6.387 5.947 5.880
10 6.383 5.946 5.933

pipe-test
# rc1 rc6 cfs-devel
1 13.39 13.16 13.20
2 13.37 13.12 13.22
3 13.19 13.17 13.26
4 13.17 13.16 13.18
5 13.16 13.22 13.23
6 13.15 13.19 13.18
7 13.18 13.42 13.21
8 13.45 13.39 13.26
9 13.40 13.40 13.28
10 13.39 13.44 13.24

Bound to single core:

lat_ctx -s 0 2
# rc1 rc6 cfs-devel
1 3.20 2.61 2.37
2 3.20 2.60 2.40
3 3.21 2.67 2.38
4 3.19 2.66 2.34
5 3.19 2.64 2.37
6 3.22 2.67 2.36
7 3.21 3.29 2.36
8 3.22 2.61 2.44
9 3.23 2.68 2.36
10 3.22 2.60 2.37

hackbench 50
# rc1 rc6 cfs-devel
1 7.528 7.950 7.538
2 7.649 8.026 7.548
3 7.613 8.160 7.580
4 7.550 8.054 7.558
5 7.563 8.373 7.559
6 7.617 8.152 7.550
7 7.593 7.831 7.562
8 7.602 8.311 7.588
9 7.589 8.010 7.552
10 7.682 8.059 7.556

pipe-test
# rc1 rc6 cfs-devel
1 10.29 9.27 8.54
2 10.30 9.29 8.54
3 10.31 9.28 8.54
4 10.29 9.27 8.54
5 10.28 9.28 8.53
6 10.30 9.28 8.53
7 10.30 9.28 8.54

I've made graphs like last time:
http://www.healthcarelinen.com/misc/lat_ctx_benchmark.png
http://www.healthcarelinen.com/misc/hackbench_benchmark.png
http://www.healthcarelinen.com/misc/pipe-test_benchmark.png
http://www.healthcarelinen.com/misc/BOUND_lat_ctx_benchmark.png
http://www.healthcarelinen.com/misc/BOUND_hackbench_benchmark.png
http://www.healthcarelinen.com/misc/BOUND_pipe-test_benchmark.png

I'll also attach the graphs, as well as my .configs.

As for the data, I really can't read much into it. I think the graphs
tell the story better (if only I could understand the story). Overall
though, a definite improvement over 2.6.23-rc1.

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