eas-dev May 2019

eas-dev@lists.linaro.org

5 participants
4 discussions

Questions about per-task utilization clamping (uclamp)

by Zhifei Yang (Arm Technology China)

(Post the questions here on behalf of Yun Hsiang) Hi all, I’d like to ask discuss some questions about uclamp in linux-power.git<http://www.linux-arm.org/git?p=linux-power.git;a=summary>. Code is based on the following version. linux-power.git<http://www.linux-arm.org/git?p=linux-power.git;a=summary> tag: topic-util_clamp-20190412 1. If a task clamped utilization is higher than a cpu capacity, should EAS bypass that cpu? kernel/sched/fair.c static int find_energy_efficient_cpu(struct task_struct *p, int prev_cpu) { … /* Skip CPUs that will be overutilized. */ util = cpu_util_next(cpu, p, cpu); <= Should this util use task clamped utilization? cpu_cap = capacity_of(cpu); if (cpu_cap * 1024 < util * capacity_margin) continue; … } 1. Will uclamp add a kernel-space API to set per-task utilization clamping? Drivers/kernel module can use this API for precise performance/power tuning. Best regards, Yun IMPORTANT NOTICE: The contents of this email and any attachments are confidential and may also be privileged. If you are not the intended recipient, please notify the sender immediately and do not disclose the contents to any other person, use it for any purpose, or store or copy the information in any medium. Thank you.

6 years, 3 months

[Query]About LISA

by Cheng-Chang Chang

Hi Linaro, I am really intrested in LISA... and may I ask some question about it? on github https://github.com/ARM-software/lisa and PDF https://developer.arm.com/-/media/developer/developers/open-source/energy-a… P.43 I just read and download the source code and try to test my android phone... however, I could not understand "Slack"'s definition in code. === Thus two types of test failures can result from these tests: 1. test_task_placement asserts that the placement was energy efficient. In a big.LITTLE system, if a low-utilisation task was placed on a big CPU then this test should be expected to fail. *2. test_slack asserts that the required bandwidth was provided. In a big.LITTLE system if a high-utilization task was placed on a LITTLE CPU then this test should be expected to fail.* === I run generic.py and can see sometimes "Slack" is negative and sometimes is positive... Negative > test failed, positive > test pass... === How to define this SLACK + or -...? I cannot understand... ==== Besides, Could I judge my algorithm is worse or better about power efficient by hikey_energy.py & est_power = self.get_power_df(experiment) est_energy = area_under_curve(est_power.sum(axis=1), method='rect (I don't have energy meter.... so.. I can just est by EM. Ofcause, I will design a power for xxx_energy.py) Really appreciate for your help. I want to write a report and see this module is so excited. Best, CCC

6 years, 3 months

[Integration Branch] Update 03-May-2019

by Dietmar Eggemann

Hi, A new EAS integration branch eas/next/integration is available on http://linux-arm.org/git?p=linux-power.git . For further information about main features, test coverage and work items for next integration have a look at: https://developer.arm.com/tools-and-software/open-source-software/linux-ker… . Best Regards, -- Dietmar

6 years, 3 months

[Integration Branch] Update 03-May-2019

by Dietmar Eggemann

6 years, 3 months

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eas-dev May 2019