On Thursday 27 January 2011 22:18:22 J. Roeleveld wrote: > 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:
> > >> 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. I'm running i7 Q 720 (4 cores, hyperthreaded) and have MAKEOPTS="-j9" without any slowdown. One or two packages (like OpenOffice) will fail and need -j=1 to emerge. Otherwise no noticeable drop in desktop responsiveness. I have not set up portage niceness so it runs with default value. Given the above what shall I set --load-average as? -- Regards, Mick
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