Re: [PATCH][2.6] Completely out of line spinlocks / i386

[William Lee Irwin III]

On Wed, 11 Aug 2004, Pavel Machek wrote:
>> Fine, so perhaps we do not want config option?

On Wed, Aug 11, 2004 at 03:13:15PM -0700, Linus Torvalds wrote:
> The inline spinlocks are _wonderful_ for seeing where the contention is in 
> a simple profile.
> In contrast, in a profile the out-of-lines ones will show "x% was spent on 
> spinlocks". Which doesn't help much when you want to see where the problem 
> is.
> This was _hugely_ useful, at least for me, for seeing what locks were 
> problematic.

Well, one trick with the kinda-sorta inline spinlocks is that they need
additional diagnostics (which are *REALLY* painful to get out of users)
to find where the overhead was, hence there were CONFIG_SPINLINE
patches to get rid of the lock section bits.


-- wli
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