filesystem optimizations (Re: comments on KDE performance tips)

[Roger Larsson]

On Thursday 16 January 2003 17:51, Alexander Kellett wrote:
> On Thu, Jan 16, 2003 at 05:30:13PM +0100, Roger Larsson wrote:
> > The nice thing is that once you start a program it reads more or less=20
exactly
> > the same stuff from the filesystem. If it, or another program, records=
=20
this=20
> > info - can be done with strace - and plays it back so that reads are do=
ne
> > immediately when the data is requested it might feel like a win but now
> > you have to be very careful not to create two threads that compete with
> > eachother. And you will still do "random" accesses. And since the origi=
nal
> > program will get cached data all the time it will quickly catch up.
> > [I have tried this]
>=20
> problems is that from what i understand libraries are
> most of the loading time and libs are not read directly
> but mmap'ed thus nothing will be seen in the strace :(
>=20

You can see the mmap calls, so you have quite a chance to know what MIGHT
be needed in future...
Maybe that would be a good enough tool? One that detects the mappings and
reads those ahead - kernel could also do that for mappings that are less to=
=20
some limit.

/RogerL

=2D-=20
Roger Larsson
Skellefte=E5
Sweden