Re: [GIT PATCH] TTY patches for 2.6.33-git

[Arjan van de Ven]

On Sun, 13 Dec 2009 07:58:44 +0100
Ingo Molnar <mingo@xxxxxxx> wrote:

> 
> * Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx> wrote:
> 
> > We've had quite a bit of BKL work this merge-window. Maybe we'll
> > even get rid of it one of these days. There are "only" about 600
> > instances of "lock_kernel()" in the tree right now ;)
> 
> I tend to use unlock_kernel() as the metric. (as it's more precisely
> greppable and it is also more indicative of the underlying complexity
> of locking, as it gets used more in more complex scenarios)

another metric is... how many times do we take the BKL for some
workload. (For example booting or compiling a kernel).
A counter like "BKLs-per-second" would be nice to expose
(and then we can track that number going up as a regression etc)

For me, a secondary metric would be "how many times do we depend on the
magic auto-drop/reget behavior".. also easy to build a counter for.

-- 
Arjan van de Ven 	Intel Open Source Technology Centre
For development, discussion and tips for power savings, 
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