Re: [PATCH 0/4 v4] sched/rt: track rt rq utilization
From: Vincent Guittot
Date: Sun Apr 15 2018 - 08:01:12 EST
Hi Dietmar,
On 15 April 2018 at 13:56, Dietmar Eggemann <dietmar.eggemann@xxxxxxx> wrote:
> 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.
The test stop after an defined amount of time with --max-time=15 in my case
>
> [...]