Re: VM tuning through fault trace gathering [with actual code]

[John Fremlin]

Rik van Riel <[e-mail]> writes:

> On 25 Jun 2001, John Fremlin wrote:
> 
> > Last year I had the idea of tracing the memory accesses of the
> > system to improve the VM - the traces could be used to test
> > algorithms in userspace. The difficulty is of course making all
> > memory accesses fault without destroying system performance.
> 
> Sounds like a cool idea.  One thing you should keep in mind though
> is to gather traces of the WHOLE SYSTEM and not of individual
> applications.

In the current patch all pagefaults are recorded from all sources. I'd
like to be able to catch read(2) and write(2) (buffer cache stuff) as
well but I don't know how . . . .

> There has to be a way to balance the eviction of pages from
> applications against those of other applications.

Of course! It is important not to regard each thread group as an
independent entity IMHO (had a big old argument about this).

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