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Re: Boot poster challenge



On Thu, 2004-11-18 at 08:36 +0100, Arjan van de Ven wrote: 
> > There's a 20 MB load of files in your readahead list and they are being
> > read for 15 seconds.  I guess a 26.60 MB/sec 'hdparm -t' suggests room
> > for improvement?  Note that this is on a 4200 RPM drive.
> 
> hmm yeah there ought to be room; I'll need to think about how to use that
> though.

Yeah I guess the fact that disk caches are loaded on a per-file basis
doesn't help either.  Because in theory: stat-ing your list takes about
3 sec and readahead on a tarball is instantaneous (both of course
without boot-time readahead).

(A kick in the dark probably, but I'm thinking a contiguous readahead
cache file kept updated with the changed files only.)

> One question: was the drive (light) mostly quiet when readahead was finished ?

Well there are occasional flashes, even if I turn off synchronous
logging (which wasn't the case when I posted the chart).  I guess I'd
have to tailor the list first.

BTW, some time ago (http://kerneltrap.org/node/view/2157) you mentioned
11,000 files being read during boot.  This list only contains 923.  Are
all the rest gnome-related?

-- 
Ziga


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