Re: locking hierarchy based on lockdep

From: Pavel Machek
Date: Wed Nov 08 2006 - 08:17:33 EST


Hi!

> > * Jason Baron <jbaron@xxxxxxxxxx> wrote:
> >
> > > I've implemented this as a /proc file, but Ingo suggested that it
> > > might be better for us to simply produce an adjaceny list, and then
> > > generate a locking hierarchy or anything else of interest off of that
> > > list.... [...]
> >
> > this would certainly be the simplest thing to do - we could extend
> > /proc/lockdep with the list of 'immediately after' locks separated by
> > commas. (that list already exists: it's the lock_class.locks_after list)
> >
> > i like your idea of using lockdep to document locking hierarchies.
> >
> > Ingo
> >
>
> hi,
>
> So below is patch that does what you suggest, although i had to add the
> concept of 'distance' to the patch since the locks_after list loses this
> dependency info afaict. i also wrote a user space program to sort the
> locks into cluster of interelated locks and then sorted within these
> clusters...the results show one large clump of locks...perhaps there are a
> few locks that time them all together like scheduler locks...but i
> couldn't figure out which ones to exclude to make the list look really
> pretty (also, there could be a bug in my program :). Anyways i'm including
> my test program and its output too...

Perhaps presenting it as a tree is worth it?
Pavel
--
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html
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