[kaffe] Lock patch

Guilhem Lavaux guilhem at kaffe.org
Tue Mar 8 10:00:08 PST 2005


Timothy Stack wrote:
> 
> On Mar 8, 2005, at 5:38 AM, Helmer Krämer wrote:
> 
>>
>> If *lkp does not point to a heavy lock, a new one is allocated on the 
>> heap.
> 

Hi Tim,

> 
> I just want to interject a little note here, which I'm not sure is even 
> relevant...
> Basically, Pat Tullmann (i think) once observed that the maximum number
> of heavy locks needed by the system was the same as the number of threads
> in the system.  In other words, every thread is either: running, blocked 
> trying
> to obtain a lock, or blocked in an Object.wait().  Therefore, you could
> preallocate all of the lock objects when creating threads and not have to
> try and allocate memory when taking a lock.  Of course, this may not apply
> anymore since y'all seem to be leaving the heavies in place.  Anyways,
> there is an implementation of this in the janosvm if you're interested.
> 

Yep. I've though about caching the semaphore but not the heavy lock. As 
I've detected another deadlock with the new implementation I will 
stabilize it a little more then maybe add a cache in threadData as 
JanosVM do.

Thanks Tim !

Regards,

Guilhem.




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