Hi

I was wandering if BOINC support power-saving hardware features (like HLT instruction, http://en.wikipedia.org/wiki/HLT). If it doesn't, is it potentially possible to implement (it is not a proposal, i'm just curious about technical possibility)?

The reason of this question: i've been crunching for several years, but there are people who want to save few $/year so much that they just don't care about participating in projects@home. For example, users of win98 didn't spend anything on crunching because there weren't any powersaving features, but now, for multicore CPUs this question becomes important.
Personally i don't care about power-saving problem, but if BOINC could be tuned to run as system idle process (controlling power-saving), it would be easier to aggitate -- "hey, it won't take a penny from you".

Projects under BOINC run at slightly higher than Idle priority, only taking CPU cycles that are really left over. It won't run when you let your system go into hibernation (which is normal), but there is a catch there. It's advised to use the "Suspend work if no mouse/keyboard activity in last x.xx minutes" option prior to allowing your computer to go into low-power, or hibernation mode.

So in other words, the option is available already.

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Yes, i see that. Standby is also an answer, but let me to concretize the question.

Suppose i'm working in ms word whole day, so the system doesn't go to power-saving mode, but cpu usage is 1-3%, so (as i understand) "system idle process" (http://en.wikipedia.org/wiki/System_Idle_Process) run HLT and CPU shuts some of it's parts down. If i run boinc, the system idle process doesn't get cpu time so CPU use full power. Again, IMO, it's a barely economy because RAM, MB, HDD, display are still active, but it's interesting if it is technically possible to run HLT by BOINC, so it could be "a replacement" to system idle process?

BOINC is designed to use otherwise unused CPU cycles of your computer. How could it do that if there are none because of a HLT directive having been executed?

BOINC is designed to use otherwise unused CPU cycles of your computer. How could it do that if there are none because of a HLT directive having been executed?

Then it follows that when system idle process has 99% cpu usage, your cpu is really doing nothing? It should be cold then.

BOINC is designed to use otherwise unused CPU cycles of your computer. How could it do that if there are none because of a HLT directive having been executed?

Then it follows that when system idle process has 99% cpu usage, your cpu is really doing nothing? It should be cold then.

When idle process takes 99% the CPU does nothing.
Will it be cold or not actually depends from OS. Advanced OS can use different power saving modes available in new CPUs, ancient windows versions could do just wait loop even w/o halt instruction - CPU will be used just as heater then. What windows version is doing with what CPU you can learn from some manuals and Intel's optimization guide offers nice overview of power saving modes current Intel's CPU supports.

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