Re: [gentoo-user] Re: Simultaneously emerging multiple packages with same dependencies

[Mick]

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 <joost@××××××××.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