On Tue, 16 Apr 2013 11:27:44 +0200 Wendy Lin wrote:
> On 15 April 2013 20:37, Phong Vo <[email protected]> wrote:
> >
> > Exhausting VA space is not likely but keeping processes behaving nicely
> > toward
> > one another should be a good thing. You need to think about cases when many
> > processes do large I/O at the same time and the physical memory available on
> > the machine is far less than what the VA space can accommodate.
> >
> > It's little known but Sfio does adaptive buffer filling to reduce read I/O,
> > esp. when many seeks are done (hence most read data are wasted). The same
> > strategy could be adapted to mapped I/O. We'll look into that.
> Commenting here since it affects the builtin grep
> Phong, please keep the implementation KISS ("Keep it simple, stupid").
> The VM system in Linux and AIX better work with large mappings which
> do not change than a moving target which changes frequently.
> In a 64bit application libast should map the whole file and let the
> kernel worry about the rest.
we are concerned about ast/sfio being a good neighbor and not hogging all
resources
its fine for every app on a single user desktop to map in 16Gib files
how about each or 2^t threads doing that with 2^f different files of size 2^z
there has to be a point of diminishing returns
and that is what sfio concerns itself with
so that ast apps do not have to worry
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