Messages in this thread | | | Subject | Re: power increase issue on light load | From | "Alex,Shi" <> | Date | Fri, 24 Jun 2011 08:41:39 +0800 |
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On Thu, 2011-06-23 at 17:02 +0800, Peter Zijlstra wrote: > On Thu, 2011-06-23 at 10:43 +0800, Alex,Shi wrote: > > commit c8b281161dfa4bb5d5be63fb036ce19347b88c63 causes light load > > benchmark use more than 10% system power on platform NHM-EP and laptop > > Thinkpad T410 etc. The benchmarks are specpower and bltk office. > > > > I tried to track this issue, but only find deep C sate time reduced > > much, about from 90% to 30~40%, the C0 or C1 state increase much on > > different machines. > > > > Powertop just hints RES interrupts has a bit more. but when I try "perf > > probe native_smp_send_reschedule". I didn't find much. > > > > I also checked the /proc/schedstat, just can sure the load_balance was > > called a bit more frequency. but pull_task() was called really rare. > > > > > > The following are the /proc/schedstat increased number in about 300' when do bltk-office. > > The getting command is here: > > #on a 16 LCPU system, with 3 level domain, 0,1,2, so all domain number > > is 48, the domain statistic number is 2 + 36, so fs=38, > > > > $cat /proc/schedstat > schedstat ; sleep x ; cat /proc/schedstat >> > > schedstat ; cat schedstat | grep domain | sed '49 i \\n' | awk -v fs=38 > > 'BEGIN { RS=""; FS=" " } { if ( NR ==1) for (i=0; i<NF; i++) > > { value1[i]=$i ; } ; if ( NR ==2) for (i=0; i<NF; i++) { value2[i]= > > $i } } END {ORS=" "; for (i=0;i<NF;i++){ if (i%fs == 0) ll="\n"; else > > ll=""; print value2[i] - value1[i] ll }; print "\n" }' > > /proc/schedstat is already a massive pain to interpret and then you go > and mangle things even more and expect me to try and understand that > crap? I don't think so, life is too short. > > > BTW, the imbalance increasing is due to the SCALE increase about 1024. > > > Any ideas of this? > > What happens if you try something like the below. Increased imbalance > might lead to more load-balance action, which might lead to more task > migration/waking up of cpus etc. > > If the below makes any difference, Nikhil's changes have a funny that > needs to be caught.
Yes, it most remove the commit effect, So the power recovered.
In fact the only suspicious I found is large imbalance, but that it is the commit want to...
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