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* Re: [BENCHMARK] vm swappiness with contest
@ 2002-12-27 13:13 Paolo Ciarrocchi
  0 siblings, 0 replies; 13+ messages in thread
From: Paolo Ciarrocchi @ 2002-12-27 13:13 UTC (permalink / raw)
  To: conman, linux-kernel; +Cc: ciarrocchi, akpm

From: Con Kolivas <conman@kolivas.net>
[...]
> Paolo if I was to choose a number from these values I'd suggest lower than 60 
> rather than higher, BUT that is because the io load effects become a real 
> problem when the kernel is swappy - don't _really_ know what this means for 
> the rest of the time. Maybe in the 40-50 range. There seems to be a knee 
> (bend) in the curve (most noticable in dbench_load) rather than the curves 
> being linear. That knee I believe simply shows the way the algorithm for 
> swappiness basically works. I might throw a 50 at the machine as well to see 
> what that does.

Con, thank you for your time and results.
I have to confirm you that large file writes with a swappy kernel 
seems to waste time swapping data, I see it with the resp tool too.

May be we can say that a good value for a desktop enviroment is in the
40-50 range while for a server is 70-80, this because with the osdb bench
tool I get the best results with 80.

Ciao,
        Paolo 
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^ permalink raw reply	[flat|nested] 13+ messages in thread
* [BENCHMARK] vm swappiness with contest
@ 2002-12-27  5:46 Con Kolivas
  2002-12-27 10:00 ` Con Kolivas
  0 siblings, 1 reply; 13+ messages in thread
From: Con Kolivas @ 2002-12-27  5:46 UTC (permalink / raw)
  To: linux kernel mailing list; +Cc: Paolo Ciarrocchi, Andrew Morton

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Here is a family of contest benchmarks using the osdl hardware in uniprocessor 
mode on 2.5.53-mm1 while varying vm swappiness. s020 is vm swappiness=20 and 
so on:

noload:
Kernel [runs]           Time    CPU%    Loads   LCPU%   Ratio
s000 [3]                71.1    95      0       0       1.07
s020 [5]                71.9    95      0       0       1.08
s040 [5]                71.7    95      0       0       1.07
s060 [5]                71.3    96      0       0       1.07
s080 [5]                71.3    95      0       0       1.07
s100 [5]                71.6    95      0       0       1.07

cacherun:
Kernel [runs]           Time    CPU%    Loads   LCPU%   Ratio
s000 [3]                68.4    99      0       0       1.02
s020 [5]                68.8    99      0       0       1.03
s040 [5]                68.7    99      0       0       1.03
s060 [5]                68.6    99      0       0       1.03
s080 [5]                68.5    99      0       0       1.03
s100 [5]                68.7    99      0       0       1.03

process_load:
Kernel [runs]           Time    CPU%    Loads   LCPU%   Ratio
s000 [3]                119.0   57      49      41      1.78
s020 [5]                119.4   57      49      41      1.79
s040 [5]                118.6   57      48      41      1.78
s060 [5]                117.6   57      47      41      1.76
s080 [5]                119.5   57      49      41      1.79
s100 [5]                118.4   58      48      40      1.77

dbench_load:
Kernel [runs]           Time    CPU%    Loads   LCPU%   Ratio
s000 [3]                191.6   41      1       43      2.87
s020 [5]                195.5   40      1       44      2.93
s040 [5]                197.9   41      1       43      2.96
s060 [5]                331.4   32      0       23      4.96
s080 [5]                439.4   24      0       10      6.58
s100 [5]                883.6   13      1       9       13.24
The first of the massive effect of changing this value. A recurring theme is 
large file writes with a swappy kernel seems to waste time swapping data 
because of the IO data. Obviously none of these IO loads use the o_direct 
option.

ctar_load:
Kernel [runs]           Time    CPU%    Loads   LCPU%   Ratio
s000 [3]                113.4   81      3       10      1.70
s020 [5]                103.3   80      2       9       1.55
s040 [5]                110.0   79      3       9       1.65
s060 [5]                103.0   80      3       9       1.54
s080 [5]                104.4   80      2       8       1.56
s100 [5]                100.2   80      2       8       1.50
Slightly slower with an unswappy kernel

xtar_load:
Kernel [runs]           Time    CPU%    Loads   LCPU%   Ratio
s000 [3]                139.2   65      3       8       2.09
s020 [5]                128.7   70      2       7       1.93
s040 [5]                152.8   59      3       7       2.29
s060 [5]                137.0   64      2       6       2.05
s080 [5]                124.6   66      2       6       1.87
s100 [5]                127.6   66      2       6       1.91
Up and down, no firm pattern

io_load:
Kernel [runs]           Time    CPU%    Loads   LCPU%   Ratio
s000 [3]                121.8   63      21      17      1.82
s020 [5]                125.9   61      22      17      1.89
s040 [5]                130.1   59      22      17      1.95
s080 [5]                174.6   47      27      15      2.62
s100 [5]                208.1   42      25      11      3.12
Increase the swappiness, increase the kernel compile time as dbench_load does


io_other:
Kernel [runs]           Time    CPU%    Loads   LCPU%   Ratio
s000 [3]                103.6   73      18      17      1.55
s020 [5]                135.4   62      25      18      2.03
s040 [5]                157.7   57      28      18      2.36
s060 [5]                188.1   48      32      16      2.82
s080 [5]                246.2   37      38      15      3.69
s100 [5]                378.8   24      45      11      5.67
Another massive change.

read_load:
Kernel [runs]           Time    CPU%    Loads   LCPU%   Ratio
s000 [3]                89.7    80      15      7       1.34
s020 [5]                91.1    79      13      6       1.36
s040 [5]                90.6    79      12      6       1.36
s060 [5]                90.3    79      12      6       1.35
s080 [5]                90.3    79      12      6       1.35
s100 [5]                92.2    78      10      5       1.38

list_load:
Kernel [runs]           Time    CPU%    Loads   LCPU%   Ratio
s000 [3]                81.8    85      0       9       1.23
s020 [5]                81.9    85      0       9       1.23
s040 [5]                82.0    85      0       9       1.23
s060 [5]                82.2    85      0       8       1.23
s080 [5]                82.7    85      0       8       1.24
s100 [5]                83.1    85      0       8       1.24

mem_load:
Kernel [runs]           Time    CPU%    Loads   LCPU%   Ratio
s000 [3]                233.2   32      65      1       3.49
s020 [5]                172.3   42      50      1       2.58
s040 [5]                163.8   46      44      1       2.45
s060 [5]                192.2   39      38      1       2.88
s080 [5]                186.4   42      37      0       2.79
s100 [5]                128.2   57      37      1       1.92
Here it seems only the extreme values make a difference. Un unswappy kernel 
makes it slow down significantly, whereas a swappy kernel speeds it up 
significantly.

Paolo if I was to choose a number from these values I'd suggest lower than 60 
rather than higher, BUT that is because the io load effects become a real 
problem when the kernel is swappy - don't _really_ know what this means for 
the rest of the time. Maybe in the 40-50 range. There seems to be a knee 
(bend) in the curve (most noticable in dbench_load) rather than the curves 
being linear. That knee I believe simply shows the way the algorithm for 
swappiness basically works. I might throw a 50 at the machine as well to see 
what that does.

Con
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^ permalink raw reply	[flat|nested] 13+ messages in thread

end of thread, other threads:[~2002-12-31  7:12 UTC | newest]

Thread overview: 13+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2002-12-27 13:13 [BENCHMARK] vm swappiness with contest Paolo Ciarrocchi
  -- strict thread matches above, loose matches on Subject: below --
2002-12-27  5:46 Con Kolivas
2002-12-27 10:00 ` Con Kolivas
2002-12-28  6:16   ` Con Kolivas
2002-12-28  6:26     ` Andrew Morton
2002-12-28  8:05     ` Linus Torvalds
2002-12-31  5:58     ` Con Kolivas
2002-12-31  6:08       ` Andrew Morton
2002-12-31  6:24         ` Con Kolivas
2002-12-31  6:37           ` Andrew Morton
2002-12-31  6:57             ` Con Kolivas
2002-12-31  7:08               ` Andrew Morton
2002-12-31  7:20                 ` Con Kolivas

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