Wednesday 04/08/2010

This month's meetings

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IRC Nick

Amit Kucheria


Amit Arora


Vishwanath Sripathy


Bobby Bhatacharia


Srinivas Kalaga


Yong Shen



  • Review action items from last meeting
  • Blueprint status



Master blueprint for PM WG


PM Tools




Action Items from this Meeting

  • ACTION: Robin and Srinivas to send mail to team, to target the ftrace patches for upstream.
  • ACTION: Amit K to send email regarding power aware scheduling by Intel (CONFIG_SCHED_MC & CONFIG_SCHED_SMT ?) Yes!

  • ACTION: Yong Shen to test Amit Arora's powertop patches and powerdebug tool.
  • ACTION: Yong Shen to investigate plugging in cpufreq framework for freescale boards
  • ACTION: Amit Arora to creat a new wiki page for instructions on how to setup your own git repo on
  • ACTION: Amit K to talk to jeremy about power domain framework
  • ACTION: Amit Arora and Yong to discuss about reporting sensor information (hwmon, or some other source for ARM?)

Action Items from Previous Meeting

  • ACTIVE (Immediate):
    • ACTION: Bobby to investigate android contraints (e.g. display keep-alive): CLOSED
      • Bobby sent a mail. Considering closed.
    • ACTION: Srinivas to add ftrace item to task list and send patches to linaro: CLOSED
      • Srinivas has emailed the patches to team. Needed to get time-stamps when system is entering low power state with various workloads
    • ACTION: Vishwa to create a new blue print for the instrumentation of cpuidle related work: CLOSED
      • Blue print created and assigned to Vishwa.
    • ACTION: Amit Arora to create tarballs of his current work and share it internally for testing: CLOSED
      • considered done, git tree now available on
    • ACTION: Amit Kucheria and Vishwa to get inputs from community on the issues related to CPUIDLE governor: POSTPONED until instrumentation work
  • ACTIVE (Long Term) :
    • ACTION: Srinivas to provide details of where he believes userspace - kernel interaction is required. (low prio)
    • ACTION: Bobby to check on multi-core boards availability (request open)
    • ACTION: ARM to discuss giving out internal Eclipse based tool (similar to powertop) (no ETA as of now)
    • ACTION: ARM to share internal instrumentation flow (BAB: we might also align with Linaro on workload discussions)
      • Might take couple of months


  • ftrace patches part of larger tool work inside ARM, perhaps the ftrace patch doesn't need to wait for the entire tool and can be sent upstream
  • power aware scheduling using perf counters, cache misses/hits, TLB hits/misses?
    • ties into instrumentation work for cpuidle being done by Vishwa
  • Discussion regarding power domain framework
    • Similar to clock framework
    • Does SRF replacement handle it? No, according to Vishwa.
  • displaying sensors information - is it duplicating work done by lm-sensors tool?
    • figure out what drivers are using hwmon
    • perhaps it would make sense to use the lm-sensor library (is there any?) to grab this info?
  • API to read performance counters
    • arch/arm/kernel/pmu.h perf_event.c
    • No documentation? (Perhaps we should provide docs?)

WorkingGroups/PowerManagement/Meetings/2010-08-04 (last modified 2010-08-04 09:21:22)