On 05/01/2018 11:43, Viresh Kumar wrote:
Hello,
I did some comparisons of Pelt and Walt and have some very interesting performance results that I wanted to share with all of you. I haven't got any power numbers as I don't have setup for that.
Key points:
All the tests were done on Hikey960, with a 5V Fan placed over the SoC to cool it down.
HDMI port was disconnected while running tests.
CONFIG_SCHED_TUNE was configured out to keep things simple.
Only the PCmark bench was tested, with help of workload automation.
Below number shows the average out of 3 runs, performed during a single kernel boot cycle.
Pelt 8/16/32 are the half-life periods.
While testing Pelt, CONFIG_WALT was disabled.
+------------------+----------+------------+------------+-----------+ | | | | | | | Test name | WALT | Pelt 8 ms | Pelt 16 ms | Pelt 32 ms| +------------------+----------+------------+------------+-----------+ | | | | | | | DataManipulation | 5341 | 5561 | 5453 | 5400 | | | | | | | | PhotoEditingV2 | 9015 | 8577 | 7911 | 6043 | | | | | | | | VideoEditing | 0 | 4291 | 3746 | 3755 | | | | | | | | WebV2 | 6202 | 6448 | 5465 | 4648 | | | | | | | | Workv2 | 0 | 5697 | 5069 | 4517 | | | | | | | | WritingV2 | 4302 | 4549 | 3811 | 3306 | +------------------+----------+------------+------------+-----------+
As you can see in the results Pelt 8 is very much comparable to the Walt results now. Hurray ? :)
Modulating the pelt period to approach the walt results is a good approach to remove the walt code, IMO.
To make sure that is going to the right direction, may be you can the same with benchmarks measuring latencies / responsiveness ?
A detailed report is present here with some more useful numbers:
Why the amplitude of the differences for the TIS are high between different rounds ? I mean the delta between min and max.
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