Re: [RFC PATCH v2 00/17] Core scheduling v2

[Phil Auld]

On Mon, Apr 29, 2019 at 09:25:35PM +0800 Li, Aubrey wrote:
> On 2019/4/29 14:14, Ingo Molnar wrote:
> > 
> > * Li, Aubrey <aubrey.li@xxxxxxxxxxxxxxx> wrote:
> > 
> >>> I suspect it's pretty low, below 1% for all rows?
> >>
> >> Hope my this mail box works for this...
> >>
> >> .-------------------------------------------------------------------------------------------------------------.
> >> |NA/AVX vanilla-SMT     [std% / sem%] | coresched-SMT   [std% / sem%]     +/- |  no-SMT [std% / sem%]    +/-  |
> >> |-------------------------------------------------------------------------------------------------------------|
> >> |  1/1        508.5     [ 0.2%/ 0.0%] |         504.7   [ 1.1%/ 0.1%]    -0.8%|   509.0 [ 0.2%/ 0.0%]    0.1% |
> >> |  2/2       1000.2     [ 1.4%/ 0.1%] |        1004.1   [ 1.6%/ 0.2%]     0.4%|   997.6 [ 1.2%/ 0.1%]   -0.3% |
> >> |  4/4       1912.1     [ 1.0%/ 0.1%] |        1904.2   [ 1.1%/ 0.1%]    -0.4%|  1914.9 [ 1.3%/ 0.1%]    0.1% |
> >> |  8/8       3753.5     [ 0.3%/ 0.0%] |        3748.2   [ 0.3%/ 0.0%]    -0.1%|  3751.3 [ 0.4%/ 0.0%]   -0.1% |
> >> | 16/16      7139.3     [ 2.4%/ 0.2%] |        7137.9   [ 1.8%/ 0.2%]    -0.0%|  7049.2 [ 2.4%/ 0.2%]   -1.3% |
> >> | 32/32     10899.0     [ 4.2%/ 0.4%] |       10780.3   [ 4.4%/ 0.4%]    -1.1%| 10339.2 [ 9.6%/ 0.9%]   -5.1% |
> >> | 64/64     15086.1     [11.5%/ 1.2%] |       14262.0   [ 8.2%/ 0.8%]    -5.5%| 11168.7 [22.2%/ 1.7%]  -26.0% |
> >> |128/128    15371.9     [22.0%/ 2.2%] |       14675.8   [14.4%/ 1.4%]    -4.5%| 10963.9 [18.5%/ 1.4%]  -28.7% |
> >> |256/256    15990.8     [22.0%/ 2.2%] |       12227.9   [10.3%/ 1.0%]   -23.5%| 10469.9 [19.6%/ 1.7%]  -34.5% |
> >> '-------------------------------------------------------------------------------------------------------------'
> > 
> > Perfectly presented, thank you very much!
> 
> My pleasure! ;-)
> 
> > 
> > My final questin would be about the environment:
> > 
> >> Skylake server, 2 numa nodes, 104 CPUs (HT on)
> > 
> > Is the typical nr_running value the sum of 'NA+AVX', i.e. is it ~256 
> > threads for the 128/128 row for example - or is it 128 parallel tasks?
> 
> That means 128 sysbench threads and 128 gemmbench tasks, so 256 threads in sum.
> > 
> > I.e. showing the approximate CPU thread-load figure column would be very 
> > useful too, where '50%' shows half-loaded, '100%' fully-loaded, '200%' 
> > over-saturated, etc. - for each row?
> 
> See below, hope this helps.
> .--------------------------------------------------------------------------------------------------------------------------------------.
> |NA/AVX vanilla-SMT     [std% / sem%]     cpu% |coresched-SMT   [std% / sem%]     +/-     cpu% |  no-SMT [std% / sem%]   +/-      cpu% |
> |--------------------------------------------------------------------------------------------------------------------------------------|
> |  1/1        508.5     [ 0.2%/ 0.0%]     2.1% |        504.7   [ 1.1%/ 0.1%]    -0.8%    2.1% |   509.0 [ 0.2%/ 0.0%]   0.1%     4.3% |
> |  2/2       1000.2     [ 1.4%/ 0.1%]     4.1% |       1004.1   [ 1.6%/ 0.2%]     0.4%    4.1% |   997.6 [ 1.2%/ 0.1%]  -0.3%     8.1% |
> |  4/4       1912.1     [ 1.0%/ 0.1%]     7.9% |       1904.2   [ 1.1%/ 0.1%]    -0.4%    7.9% |  1914.9 [ 1.3%/ 0.1%]   0.1%    15.1% |
> |  8/8       3753.5     [ 0.3%/ 0.0%]    14.9% |       3748.2   [ 0.3%/ 0.0%]    -0.1%   14.9% |  3751.3 [ 0.4%/ 0.0%]  -0.1%    30.5% |
> | 16/16      7139.3     [ 2.4%/ 0.2%]    30.3% |       7137.9   [ 1.8%/ 0.2%]    -0.0%   30.3% |  7049.2 [ 2.4%/ 0.2%]  -1.3%    60.4% |
> | 32/32     10899.0     [ 4.2%/ 0.4%]    60.3% |      10780.3   [ 4.4%/ 0.4%]    -1.1%   55.9% | 10339.2 [ 9.6%/ 0.9%]  -5.1%    97.7% |
> | 64/64     15086.1     [11.5%/ 1.2%]    97.7% |      14262.0   [ 8.2%/ 0.8%]    -5.5%   82.0% | 11168.7 [22.2%/ 1.7%] -26.0%   100.0% |
> |128/128    15371.9     [22.0%/ 2.2%]   100.0% |      14675.8   [14.4%/ 1.4%]    -4.5%   82.8% | 10963.9 [18.5%/ 1.4%] -28.7%   100.0% |
> |256/256    15990.8     [22.0%/ 2.2%]   100.0% |      12227.9   [10.3%/ 1.0%]   -23.5%   73.2% | 10469.9 [19.6%/ 1.7%] -34.5%   100.0% |
> '--------------------------------------------------------------------------------------------------------------------------------------'
> 

That's really nice and clear.

We start to see the penalty for the coresched at 32/32, leaving some cpus more idle than otherwise.  
But it's pretty good overall, for this benchmark at least.

Is this with stock v2 or with any of the fixes posted after? I wonder how much the fixes for
the race that violates the rule effects this, for example. 



Cheers,
Phil


> Thanks,
> -Aubrey

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