Speeding up live cd boot through optimizing file layout

[Hervé Fache]

I might have missed a 's' for plural, but of course placing ONE file
far from the others would be very stupid!

The other advantage of having the most accessed files at the edge is
that there is more data at one given radius (it was actually implied
in a previous post). And before mdz reminds me, I know it's a spiral!

So there might be some good benefits to get from this scheme...


On 5/30/06, Matt Zimmerman <mdz at ubuntu.com> wrote:
> On Mon, May 29, 2006 at 04:25:18PM -0700, plougher wrote:
> >
> > Matt Zimmerman wrote:
> > >Optimizations like this are rarely so simple, and certainly not in this
> > >case.  The advantage of the outer edges is in throughput, not latency.
> > >Placing a file there, away from most other files, requires that the drive
> > >seek a long way to get at it.  Meanwhile, caching means that files which
> > are
> > >accessed very frequently will be held in memory anyway, so this could even
> > >be a net loss in performance.
> >
> > By and large this is correct.  However, there are a couple of reasons why
> > moving files accessed together at start-up to the edge of the disk works
> > well on Squashfs.
>
> The above was written in response to a proposal to move the single most
> frequently accessed file to the edge of the disk; what you are describing is
> something quite different: grouping the files read at boot in one place on
> the disc.
>
> This, in fact, has a reasonable chance of improving performance, since all
> of these files are read in a single pass by /etc/init.d/readahead.
>
> --
>  - mdz
>
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>


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