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  1. 14 Aug, 2006 1 commit
  3. 11 Aug, 2006 4 commits
    • Rafa Bilski's avatar
      [CPUFREQ] Longhaul - Disable arbiter · 179da8e6
      Rafa Bilski authored 
      ACPI C3 works for "Powersaver" processors, so use it only for them.

Older CPU will change frequency on "halt" only. But we can protect transition
in two ways:
- by ACPI PM2 register, there is "bus master arbiter disable" bit.
  This isn't tested because VIA mainboards don't have PM2 register,
- by PLE133 PCI/AGP arbiter disable register.
  There are two bits in this register. First is "PCI arbiter disable",
  second "AGP arbiter disable". This is working on VIA Epia 800 mainboards.

Test on bm_control is more proper because this is true
when PM2 register exist.
Signed-off-by: default avatarRafa³ Bilski <rafalbilski@interia.pl>
Signed-off-by: default avatarDave Jones <davej@redhat.com>
      179da8e6
    • 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
  5. 06 Aug, 2006 35 commits
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