Re: xeon processors

On Sat, Jun 26, 2004 at 07:31:59PM -0600, Scott Marlowe wrote:
> On Fri, 2004-06-25 at 14:13, Jaime Casanova wrote:
> > Hi all,
> >
> > Can anyone tell me if postgresql has problems with xeon processors?
> > If so, there is any fix or project of fix it?
>
> To PostgreSQL, there's no difference between a dual CPU machine with no
> hyperthreading, and a single CPU machine with hyperthreading.

At some point there was trouble with spinlocks on some of the newer
Xeons (maybe those with hyperthreading?). I think there was a good deal
of discussion and resulting development because of that. According to
my archives it seems to be around december 2003. There's even a CVS
entry, listed by cvs2cl as

2003-12-27 17:58 tgl

* src/: backend/storage/lmgr/s_lock.c, include/storage/s_lock.h:
Improve spinlock code for recent x86 processors: insert a PAUSE
instruction in the s_lock() wait loop, and use test before
test-and-set in TAS() macro to avoid unnecessary bus traffic.
Patch from Manfred Spraul, reworked a bit by Tom.

Not sure if this made the 7.4.3 release ...

--
Alvaro Herrera (<alvherre[a]dcc.uchile.cl>)
"You knock on that door or the sun will be shining on places inside you
that the sun doesn't usually shine" (en Death: "The High Cost of Living")