Re: [gentoo-amd64] Re: Unexpected side effect of GCC 4

[Jack Lloyd <lloyd@randombit.net>]

On Mon, Nov 06, 2006 at 01:59:33PM +0100, Hemmann, Volker Armin wrote:
> On Monday 06 November 2006 13:49, Jack Lloyd wrote:
> > On Mon, Nov 06, 2006 at 01:05:31PM +0100, Hemmann, Volker Armin wrote:
> > > lets ask the other way round. Why should it speed up anything to have
> > > X>number of cores? Instead of a single thread per core, compiling
> > > happily, you have two or more competing for one core and regularly kick
> > > out each others data from the cache.
> >
> > To account for I/O wait states
> 
> and how often does something wait for io and how often does some data is 
> purged from the cache, because the other make instance is activated?
>
> When I switched from j2 to j1, compiling did not take any longer - but the box 
> way much more usable.

OK. <shrug> On my dual core machine, -j3 seems to be the sweet
spot. Simply because something does not work for you does not mean it
is going to be universally a bad idea.
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