Re: Ottawa - kernel hackers ...

[Alan Cox <alan redhat com>]

> 	eg. (and I pick on GConf again) if you start up Gnome - it does in the
> worst case in the order of a:
> 
> 	time find ~/.gconf -name '*.xml' -exec cat {} > /dev/null \;

I'd hope it doesn't run cat for each one 8)

> scattering a single, huge, uniformly unused chunk of memory across the
> disk in 1000 tiny fragments points to some underlying brokenness
> somewhere. [ RH 8.0 stock kernel ]. Of course - OTOH, perhaps the X
> server is splitting it into tiles internally - but even so ...

Entropy. We do actually try and build bigger chunks but its an almost
insoluble problem. We dont know the properties of the image. If it was
mmapped and file backed it would be fine

> 	we can infer that it's the unaccounted for 8seconds that are seek time
> on an unloaded system - but can those numbers be got more easily /
> reliably ?

Most of those seem to be loading copies of cat I'd guess. 

> 	Also - is there an easy way to totally empty any disk caching to easily
> simulate cold start ( I believe an unmount / remount of a partition
> could do that - but not wanting to re-partition makes that a painful
> option ).

Not really. You can eliminate the seek part for testing however by using
ramfs