On 03/16/2018 12:25 PM, Vincent Guittot wrote:
[...]
For a 15 seconds long test on a hikey 6220 (octo core cortex A53 platfrom),
the cpufreq statistics outputs (stats are reset just before the test) :
$ cat /sys/devices/system/cpu/cpufreq/policy0/stats/total_trans
without patchset : 1230
with patchset : 14
If we replace the cfs thread of rt-app by a sysbench cpu test, we can see
performance improvements:
- Without patchset :
Test execution summary:
total time: 15.0009s
total number of events: 4903
total time taken by event execution: 14.9972
per-request statistics:
min: 1.23ms
avg: 3.06ms
max: 13.16ms
approx. 95 percentile: 12.73ms
Threads fairness:
events (avg/stddev): 4903.0000/0.00
execution time (avg/stddev): 14.9972/0.00
- With patchset:
Test execution summary:
total time: 15.0014s
total number of events: 7694
total time taken by event execution: 14.9979
per-request statistics:
min: 1.23ms
avg: 1.95ms
max: 10.49ms
approx. 95 percentile: 10.39ms
Threads fairness:
events (avg/stddev): 7694.0000/0.00
execution time (avg/stddev): 14.9979/0.00
The performance improvement is 56% for this use case.
How do you get this number? Normally we use the 'total time' value.
[...]
