Mailinglist Archive: opensuse (1620 mails)

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[opensuse] Re: Task & Resource Management (evolution? or NIH syndrome?)
Carlos E. R. wrote:
On modern CPUs, you use less electricity by having the task run as fast
as possible, then fully idling the cpu at the end, that by running it
slowly. I doubt this, specially if the cpu runs at a lower clock, but
there are apparently studies on this. I'm not sure about the fan and
cabinet heat control, though.
Since I use my excess heat to heat my home about 8 months out
of the year, it doesn't go to waste. I used to go through about 1.5 "cords"
of wood ea/winter.

If you want to bring in clock speed, you can adjust that with the
cpu governor as well as the "cpupower" command -- restrict it to 100% of
your lowest cpu-freq. That should keep the cache busy but use minimal
extra power. That said, things are almost always a bit specific to a
particular work load, but set the cpu and ionice to minimal (ionice -c3 nice -19
for the lowest jobs). Since my linux server has all my data, I have
a another sched-task to bump-UP any "smb" processes running as me.

I have more uses of ionice -c2 -nX (best effort;X:0-7)
as well as using different cpunice (aka 'nice') values for different tasks.

I.e. many of my background processes are resource controlled
and tuned to my normal usage patterns. Generally I use the CFQ cpu
scheduler with the default auto-grouping -- that was a HUGE improvement
over earlier schedulers. I can run a kernel build with 'make -j' and
usually have no effect on interactive tasks. Usually I go for "-j <#cpus*1.3>"
for optimal balance between disks and cpu's. I check for changes to
verify they actually help -- if not, I try to roll things back to defaults.

A recent problem caused by Xd: random changes in the cgroup
format -- with the more useful features being hidden away from the "/sys"
interface. Haven't had time to deal with that yet. *sigh*....

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