Re: [PATCH 05/19] sched/numa: Use task faults only if numa_group is not yet setup

[Peter Zijlstra]

On Mon, Jun 04, 2018 at 03:30:14PM +0530, Srikar Dronamraju wrote:
> When numa_group faults are available, task_numa_placement only uses
> numa_group faults to evaluate preferred node. However it still accounts
> task faults and even evaluates the preferred node just based on task
> faults just to discard it in favour of preferred node chosen on the
> basis of numa_group.
> 
> Instead use task faults only if numa_group is not set.
> 
> Testcase       Time:         Min         Max         Avg      StdDev
> numa01.sh      Real:      506.35      794.46      599.06      104.26
> numa01.sh       Sys:      150.37      223.56      195.99       24.94
> numa01.sh      User:    43450.69    61752.04    49281.50     6635.33
> numa02.sh      Real:       60.33       62.40       61.31        0.90
> numa02.sh       Sys:       18.12       31.66       24.28        5.89
> numa02.sh      User:     5203.91     5325.32     5260.29       49.98
> numa03.sh      Real:      696.47      853.62      745.80       57.28
> numa03.sh       Sys:       85.68      123.71       97.89       13.48
> numa03.sh      User:    55978.45    66418.63    59254.94     3737.97
> numa04.sh      Real:      444.05      514.83      497.06       26.85
> numa04.sh       Sys:      230.39      375.79      316.23       48.58
> numa04.sh      User:    35403.12    41004.10    39720.80     2163.08
> numa05.sh      Real:      423.09      460.41      439.57       13.92
> numa05.sh       Sys:      287.38      480.15      369.37       68.52
> numa05.sh      User:    34732.12    38016.80    36255.85     1070.51
> 
> Testcase       Time:         Min         Max         Avg      StdDev 	 %Change
> numa01.sh      Real:      478.45      565.90      515.11       30.87 	 16.29%
> numa01.sh       Sys:      207.79      271.04      232.94       21.33 	 -15.8%
> numa01.sh      User:    39763.93    47303.12    43210.73     2644.86 	 14.04%
> numa02.sh      Real:       60.00       61.46       60.78        0.49 	 0.871%
> numa02.sh       Sys:       15.71       25.31       20.69        3.42 	 17.35%
> numa02.sh      User:     5175.92     5265.86     5235.97       32.82 	 0.464%
> numa03.sh      Real:      776.42      834.85      806.01       23.22 	 -7.47%
> numa03.sh       Sys:      114.43      128.75      121.65        5.49 	 -19.5%
> numa03.sh      User:    60773.93    64855.25    62616.91     1576.39 	 -5.36%
> numa04.sh      Real:      456.93      511.95      482.91       20.88 	 2.930%
> numa04.sh       Sys:      178.09      460.89      356.86       94.58 	 -11.3%
> numa04.sh      User:    36312.09    42553.24    39623.21     2247.96 	 0.246%
> numa05.sh      Real:      393.98      493.48      436.61       35.59 	 0.677%
> numa05.sh       Sys:      164.49      329.15      265.87       61.78 	 38.92%
> numa05.sh      User:    33182.65    36654.53    35074.51     1187.71 	 3.368%
> 
> Ideally this change shouldn't have affected performance.

Ideally you go on here to explain why it does in fact do affect
performance.. :-)