Re: Question about LWLockAcquire's use of semaphores instead of spinlocks

Tom Lane writes:
> 
> 
> "Robert E. Bruccoleri" <bruc@stone.congenomics.com> writes:
> > On SGI multiprocessor machines, I suspect that a spinlock
> > implementation of LWLockAcquire would give better performance than
> > using IPC semaphores.  Is there any specific reason that a spinlock
> > could not be used in this context?
> 
> Are you confusing LWLockAcquire with TAS spinlocks?

No.

> If you're saying that we don't have an implementation of TAS for
> SGI hardware, then feel free to contribute one.  If you are wanting to
> replace LWLocks with spinlocks, then you are sadly mistaken, IMHO.

This touches on my question. Why am I mistaken? I don't understand.

BTW, about 5 years ago, I rewrote the TAS spinlocks for the
SGI platform to make it work correctly. The current implementation
is fine.

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| Robert E. Bruccoleri, Ph.D. | email: bruc@acm.org                |
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