[BENCHMARK] 100Hz v 1000Hz with contest

Con Kolivas (kernel@kolivas.org)
Tue, 3 Jun 2003 13:21:44 +1000


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I've attempted to answer the question does 1000Hz hurt responsiveness in 2.5
as much as I've found in 2.4; since subjectively the difference wasn't there
in 2.5. Using the same config with preempt enabled here are results from
2.5.70-mm3 set at default 1000Hz and at 100Hz (mm31):

no_load:
Kernel [runs] Time CPU% Loads LCPU% Ratio
2.5.70-mm3 1 79 94.9 0.0 0.0 1.00
2.5.70-mm31 1 77 94.8 0.0 0.0 1.00
cacherun:
Kernel [runs] Time CPU% Loads LCPU% Ratio
2.5.70-mm3 1 76 97.4 0.0 0.0 0.96
2.5.70-mm31 1 74 98.6 0.0 0.0 0.96
process_load:
Kernel [runs] Time CPU% Loads LCPU% Ratio
2.5.70-mm3 2 108 68.5 64.5 28.7 1.37
2.5.70-mm31 2 107 69.2 67.0 29.0 1.39
ctar_load:
Kernel [runs] Time CPU% Loads LCPU% Ratio
2.5.70-mm3 3 114 70.2 1.0 5.3 1.44
2.5.70-mm31 3 105 73.3 0.7 3.8 1.36
xtar_load:
Kernel [runs] Time CPU% Loads LCPU% Ratio
2.5.70-mm3 3 123 62.6 2.3 5.7 1.56
2.5.70-mm31 3 122 61.5 2.0 4.9 1.58
io_load:
Kernel [runs] Time CPU% Loads LCPU% Ratio
2.5.70-mm3 4 116 66.4 40.6 18.8 1.47
2.5.70-mm31 4 114 65.8 41.0 19.3 1.48
io_other:
Kernel [runs] Time CPU% Loads LCPU% Ratio
2.5.70-mm3 2 116 66.4 50.0 22.2 1.47
2.5.70-mm31 2 112 67.9 46.1 21.4 1.45
read_load:
Kernel [runs] Time CPU% Loads LCPU% Ratio
2.5.70-mm3 2 104 75.0 8.2 5.8 1.32
2.5.70-mm31 2 100 76.0 7.5 7.0 1.30
list_load:
Kernel [runs] Time CPU% Loads LCPU% Ratio
2.5.70-mm3 2 95 80.0 0.0 7.4 1.20
2.5.70-mm31 2 92 82.6 0.0 5.4 1.19
mem_load:
Kernel [runs] Time CPU% Loads LCPU% Ratio
2.5.70-mm3 2 98 80.6 53.0 2.0 1.24
2.5.70-mm31 2 95 81.1 53.0 2.1 1.23
dbench_load:
Kernel [runs] Time CPU% Loads LCPU% Ratio
2.5.70-mm3 4 313 24.3 5.0 56.9 3.96
2.5.70-mm31 4 297 24.9 4.5 52.5 3.86

At first glance everything looks faster at 100Hz. However it is well known
that it will take slightly longer even with no load at 1000Hz. Taking that
into consideration and looking more at the final ratios than the absolute
numbers it is apparent that the difference is statistically insignificant,
except on ctar_load.

Previously I had benchmark results on 1000Hz which showed preempt improved the
results in a few of the loads. For my next experiment I will compare 100Hz
with preempt to 100Hz without.

Con
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