QA:Testcase Power Management alpm

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Description

A simple test to determine effect of SATA link power management settings on power consumption.
Privileges: Root
Runlevel: singleuser
ETA: 10 minutes


How to test

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Live Image Friendly
You may run this test case using the USB or CD live image if you install the powertop utility with yum install powertop
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Hotplug issues
SATA link power states other than max_performance may cause problems with hotplugable external SATA ports and devices attached to those ports may have problems. Internal devices should be unaffected.
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System must remain idle
Please do not do any other work on the system while running this test, otherwise power usage figures may be inaccurate.
  1. Make sure laptop battery is fully charged.
  2. Reboot laptop to single user mode. Refer to the Install guide for more information about single user mode
  3. Unplug AC power from the laptop.
  4. Enable the max_performance link state using the following command:
    for i in /sys/class/scsi_host/host*/link_power_management_policy; do echo max_performance > $i; done
  5. Obtain system power usage using the following command:
    powertop -d -t 60 | grep 'Power usage'
  6. Record the ACPI power usage estimate printed in Watts(W). This will be the power consumption at the max_performance setting.
  7. Enable the medium_power link state using the following command:
    for i in /sys/class/scsi_host/host*/link_power_management_policy; do echo medium_power > $i; done
  8. Obtain system power usage using the following command:
    powertop -d -t 60 | grep 'Power usage'
  9. Record the ACPI power usage estimate printed in Watts(W). This will be the power consumption at the medium_power setting.
  10. Enable the min_power link state using the following command:
    for i in /sys/class/scsi_host/host*/link_power_management_policy; do echo min_power > $i; done
  11. Obtain system power usage using the following command:
    powertop -d -t 60 | grep 'Power usage'
  12. Record the ACPI power usage estimate printed in Watts(W). This will be the power consumption at the min_power setting.

Expected Results

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Sample results
[root@laptop ~]# for i in /sys/class/scsi_host/host*/link_power_management_policy; do echo medium_power > $i; done
[root@laptop ~]# powertop -d -t 60 | grep 'Power usage'
Power usage (ACPI estimate): 22.3W (1.9 hours) 

Please add the following to the results table.

  1. Power usage for all three link power settings, max_performance, medium_power, min_power.
  2. Your smolt system profile. (no need to resubmit if you have already for one of the other tests)
  3. Please open bugs if you notice any abnormal behavior such as system hangs, kernel oops messages, serious IO performance degradation.
  4. You may return your system to its default state by running the command in step 4 again or just reboot.