On Thursday 27 January 2011 23:05:22 Paul Hartman wrote: > On Thu, Jan 27, 2011 at 3:46 PM, J. Roeleveld <jo...@antarean.org> wrote: > > On Thursday 27 January 2011 21:25:02 Paul Hartman wrote: > >> On Thu, Jan 27, 2011 at 2:15 PM, Nikos Chantziaras <rea...@arcor.de> wrote: > >> > On 01/27/2011 09:41 PM, Dale wrote: > >> >> YoYo Siska wrote: > >> >>> Yes. > >> >>> It might not be perfect, but mostly it works pretty well. > >> >>> Once make started 10 or so process, which ate all my ram, because I > >> >>> forgot to reenable swap, when I was playing with something before > >> >>> that > >> >>> > >> >>> :) > >> >>> > >> >>> yoyo > >> >> > >> >> I noticed the same thing with mine. It used a LOT of ram. I have 4Gbs > >> >> and it was up to about 3Gbs at one point and using some swap as well. > >> >> I'm hoping to max out to 16Gbs as soon as I can. May upgrade to a 6 > >> >> core CPU too. > >> >> > >> >> I wonder how much faster it would be if the work directory is put on > >> >> tmpfs? With 16Gbs, that should work even for OOo. > >> > > >> > Btw, if you're using more instances than the amount of CPUs, the > >> > result will be slow-down. > >> > > >> > With the default kernel scheduler, best if amount of CPUs + 1. (On a > >> > 4-core, that's -j5). > >> > >> Once, when building my kernel, I accidentally forgot to specify the > >> number of makes and ran "make -j all". That was a really bad idea, the > >> system became totally unresponsive for quite a long time, much longer > >> than normal kernel build time, but it did eventually finish! > > > > I have found that multi-core systems with sufficient memory can handle > > "-j" (no value) a lot better then sindle-core systems. I do on occasion > > do it with the kernel and can still continue using the system. (For > > comparison, my desktop is a 4-core AMD64 with 8GB memory) > > Strange, in my case it was an i7 920 (4 cores, hyperthreaded, appears > as 8 CPUs to Linux) with 12GB of RAM. Maybe if I prefixed it > with"nice" it would not have brought my computer to its knees... or > maybe related to the schedulers and other kernel voodoo that I don't > understand. I might try it again someday :)
That is strange, unless your harddrive is really underperforming? Or do you have all the options in the kernel selected? Btw, HyperThreading doesn't work too well when you have a lot of identical tasks. In that case, you might end up with lesser performance as there are no "usable unused" parts in your cores, but the CPU-schedules (the hardware one for HT) is looking for things to fill those last few bits with. -- Joost
