saving power in a Dell Poweredge 750.

[George Hartzell]

Oliver Fromme writes:
 > George Hartzell wrote:
 >  > I'm setting up a Dell Poweredge 750 1U server.  A friend is loaning me
 >  > space in his rack and since his rack usage is limited by power I'd
 >  > like to be as thrifty as possible.
 >  > 
 >  > I hooked my kill-a-watt meter up and ran the machine for a couple of
 >  > days and it uses 88 watts (3.90KWH/44.01H).
 >  > 
 >  > Then I kldloaded cpufreq and enabled powerd and it still uses 88 watts
 >  > (8.35KWH/93.47H).
 > 
 > Did you verify that powerd actually reduced the CPU
 > frequency?  What's the output from "sysctl dev.cpu.0"?
 > 
 > It might be enlightening to watch the following shell
 > loop for a while:
 > while :; do sysctl dev.cpu.0.freq; sleep 1; done

I hadn't actually done *that* (but I had run powerd -v for a while and
watched).  Here you go:

  (merlin)[9:11am]~>>while (1)
  while? sysctl dev.cpu.0.freq
  while? sleep 5
  while? end
  dev.cpu.0.freq: 350
  dev.cpu.0.freq: 350
  dev.cpu.0.freq: 350
  dev.cpu.0.freq: 350
  dev.cpu.0.freq: 350
  dev.cpu.0.freq: 350
  dev.cpu.0.freq: 1051
  dev.cpu.0.freq: 2102
  dev.cpu.0.freq: 1401
  dev.cpu.0.freq: 700
  dev.cpu.0.freq: 350

 > By the way, do you have an SMP system, or are you running
 > a kernel without SMP?  "sysctl machdep.cpu_idle_hlt"?

It's a uniprocessor machine, hyperthreading capable but that's
disabled in the bios.

  (merlin)[9:12am]~>>sysctl machdep.cpu_idle_hlt
  machdep.cpu_idle_hlt: 1

Thanks for thinking about this!

g.