[MACTCL] Re: Stub-linking TkAqua and threaded carbon notifier reform

[Daniel A. S. <st...@ic...>]

On 28/04/2005, at 17:21, Zoran Vasiljevic wrote:

>> AFAIU the libSystem spinlock API immediately yields on a single  
>> processor, and spins very briefly on a multiprocessor and then  
>> yields. Certainly all of CoreFoundation uses spinlocks for locking...
>
> Ah... I'd have to look into that. So, they spin but after some quantum  
> go sleep?
> I thought they were pure spin locks (just spinning, no yielding)... I  
> will look into
> this. Yes, this would mean improvements on MP machines (perhaps Apple  
> will do more
> MP machines now they rearranged the kernel to be more granular)...

the implementation on 10.3 is here:
	http://darwinsource.opendarwin.org/10.3/xnu-517/osfmk/ppc/commpage/ 
spinlocks.s
I don't know if this has changed on 10.4

as you can see, spinlock_32_lock_up immediately relinquishes, whereas  
spinlock_32_lock_mp spins 1000 times before relinquishing the current  
thread, same for the 64 bit versions.

> So. lets dig into it. If I come against something suspicious, I'll let  
> you
> know. This change won't require a TIP I suppose, also no stub-changes?

no, not for the third option, that's one of its advantages.

The other two change proposals would also only require changes to the  
internal stubs tables, so no TIP

BTW, I have committed the tkMacOSXNotify.c changes that just sync it  
with tclUnixNotfy.c, so the patches probably no longer apply cleanly, I  
will update them ASAP; or you can apply to the tree from before 25-4

Cheers,

Daniel

-- 
** Daniel A. Steffen     **  "And now for something completely
** Dept. of Mathematics  **   different"    Monty Python
** Macquarie University  **  <mailto:st...@ma...>
** NSW 2109 Australia    **  <http://www.maths.mq.edu.au/~steffen/>