Subject: Re: postgres 7.1.3
To: Joe Laffey , <port-mac68k@netbsd.org>
From: Henry B. Hotz <hotz@jpl.nasa.gov>
List: port-mac68k
Date: 11/02/2001 14:11:50
At 3:28 PM -0600 11/2/01, Joe Laffey wrote:
>Anybody able to get postgres 7.1.3 working from pkg_src? I keep getting
>_tas undefined symbol...

This doesn't solve your problem, but I can tell you what it may be: 
Postgres uses spin-locks in a few places to improve performance.  For 
a short synchronization delay it's faster to hold on to the CPU and 
busy-wait for a condition to clear than it is to take on the overhead 
of a semaphore.  This is typically done with a special CPU 
instruction called test-and-set which atomically tests a memory 
location and sets it so anyone else's test will fail.  The hardware 
implementation extends all the way down to the specific handshaking 
done for the memory access to guarantee that multi-CPU and DMA 
systems will still work correctly.

There is a lot of logic involved in patching in just the right 
assembly code for the machine being targeted.  Likely this is where 
the problem is.
-- 
The opinions expressed in this message are mine,
not those of Caltech, JPL, NASA, or the US Government.
Henry.B.Hotz@jpl.nasa.gov, or hbhotz@oxy.edu