1. 11 Aug, 2006 3 commits
    • Alexey Starikovskiy's avatar
      [CPUFREQ][2/2] ondemand: updated add powersave_bias tunable · 05ca0350
      Alexey Starikovskiy authored
      ondemand selects the minimum frequency that can retire
      a workload with negligible idle time -- ideally resulting in the highest
      performance/power efficiency with negligible performance impact.
      
      But on some systems and some workloads, this algorithm
      is more performance biased than necessary, and
      de-tuning it a bit to allow some performance impact
      can save measurable power.
      
      This patch adds a "powersave_bias" tunable to ondemand
      to allow it to reduce its target frequency by a specified percent.
      
      By default, the powersave_bias is 0 and has no effect.
      powersave_bias is in units of 0.1%, so it has an effective range
      of 1 through 1000, resulting in 0.1% to 100% impact.
      
      In practice, users will not be able to detect a difference between
      0.1% increments, but 1.0% increments turned out to be too large.
      Also, the max value of 1000 (100%) would simply peg the system
      in its deepest power saving P-state, unless the processor really has
      a hardware P-state at 0Hz:-)
      
      For example, If ondemand requests 2.0GHz based on utilization,
      and powersave_bias=100, this code will knock 10% off the target
      and seek  a target of 1.8GHz instead of 2.0GHz until the
      next sampling.  If 1.8 is an exact match with an hardware frequency
      we use it, otherwise we average our time between the frequency
      next higher than 1.8 and next lower than 1.8.
      
      Note that a user or administrative program can change powersave_bias
      at run-time depending on how they expect the system to be used.
      
      Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi at intel.com>
      Signed-off-by: Alexey Starikovskiy <alexey.y.starikovskiy at intel.com>
      Signed-off-by: default avatarDave Jones <davej@redhat.com>
      05ca0350
    • Alexey Starikovskiy's avatar
      [CPUFREQ][1/2] ondemand: updated tune for hardware coordination · 1ce28d6b
      Alexey Starikovskiy authored
      Try to make dbs_check_cpu() call on all CPUs at the same jiffy.
      This will help when multiple cores share P-states via Hardware Coordination.
      
      Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi at intel.com>
      Signed-off-by: Alexey Starikovskiy <alexey.y.starikovskiy at intel.com>
      Signed-off-by: default avatarDave Jones <davej@redhat.com>
      1ce28d6b
    • Dave Jones's avatar
      [CPUFREQ] Fix typo. · cd878479
      Dave Jones authored
      Signed-off-by: default avatarDave Jones <davej@redhat.com>
      cd878479
  2. 06 Aug, 2006 37 commits