Re: Downsides to madvise/fadvise(willneed) for application startup

[Andi Kleen]

Taras Glek <tglek@xxxxxxxxxxx> writes:

> Hello,
> I am working on improving Mozilla startup times. It turns out that
> page faults(caused by lack of cooperation between user/kernelspace)
> are the main cause of slow startup. I need some insights from someone
> who understands linux vm behavior.

I have an older patch to create dynamic bitmaps based on the last 
run and only prefetch those pages. 

It wasn't entirely a win for everything and didn't work for shared
libraries, but with some additional tuning the approach still has
potential I think, by combining memory saving with prefetching.

ftp://firstfloor.org/pub/ak/pbitmap/INTRO
http://halobates.de/dp2.pdf

For your use case the algorithm would likely need some glibc support.

-Andi

-- 
ak@xxxxxxxxxxxxxxx -- Speaking for myself only.
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