The choice was made from running analysis on a wide range of Intel
machines, old and new. We are trying to select the optimal choice for a
wide range of CPUs for a wide range of use cases. Generally speaking,
the intel-pstate governor has deeper understanding of the processor
features and can access CPU metrics that can guide it to making an
informed choice.

>From our understanding, The intel-pstate driver should be the optimal
choice for Intel Sandy Bridge CPUs onwards.  The intel-pstate driver
supports only the performance and powersave governors. In benchmarking
we didn't observe much computational difference between the too once the
CPU is fully loaded. However, cranking up or cranking down the load one
will discover that the performance setting is more responsive than
powersave. The overall compute throughput when fully loaded is the same,
it's just a case that powersave may take a little longer to crank up to
the full speed.

It makes sense to default to powersave for most scenarios, especially
for laptop users.

Pre-Intel Sandy Bridge or non-x86 CPUs will default back to the non-
intel pstate governor.

So, question:

Which kernel(s) are you referring to?

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  Bring back ondemand.service or switch kernel default governor for
  pstate - pstate now defaults to performance governor

Status in linux package in Ubuntu:
Status in systemd package in Ubuntu:
Status in linux source package in Groovy:
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Bug description:
  In a recent merge from Debian we lost ondemand.service, meaning all
  CPUs now run in Turbo all the time when idle, which is clearly

  The discussion in bug 1806012 seems misleading, focusing on p-state vs
  other drivers, when in fact, the script actually set the default
  governor for the pstate driver on platforms that use pstate.
  Everything below only looks at systems that use pstate.

  pstate has two governors: performance and powerstate. performance runs
  CPU at maximum frequency constantly, and powersave can be configured
  using various energy profiles energy profiles:

  - performance
  - balanced performance
  - balanced power
  - power

  It defaults to balanced performance, I think, but I'm not sure.

  Whether performance governor is faster than powersave governor is not
  even clear.
  cpufreq&num=5 benchmarked them, but did not benchmark the individual
  energy profiles.

  For a desktop/laptop, the expected behavior is the powersave governor
  with balanced_performance on AC and balanced_power on battery.

  I don't know about servers or VMs, but the benchmark series seems to
  indicate it does not really matter much performance wise.

  I think most other distributions configure their kernels to use the
  powersave governor by default, whereas we configure it to use the
  performance governor and then switch it later in the boot to get the
  maximum performance during bootup. It's not clear to me that's
  actually useful.

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