> > > We could use POSIX spinlocks/semaphores now but we
> > > don't because of performance, right?
> > 
> > No. As long as no one proved with test that mutexes are bad for
> > performance...
> > Funny, such test would require ~ 1 day of work.
> 
> Good question. I know the number of function calls to spinlock stuff
> is huge. Seems real semaphores may be a big win on multi-cpu boxes.

Ok, being tired of endless discussions I'll try to use mutexes instead
of spinlocks and run pgbench on my Solaris WS 10 and E4500 (4 CPU) boxes.

Vadim

> > > > We could use POSIX spinlocks/semaphores now but we
> > > > don't because of performance, right?
> > > 
> > > No. As long as no one proved with test that mutexes are bad for
> > > performance...
> > > Funny, such test would require ~ 1 day of work.
> > 
> > Good question. I know the number of function calls to spinlock stuff
> > is huge. Seems real semaphores may be a big win on multi-cpu boxes.
> 
> Ok, being tired of endless discussions I'll try to use mutexes instead
> of spinlocks and run pgbench on my Solaris WS 10 and E4500 (4 CPU) boxes.

I have updated the TODO list with:

    * Improve spinlock code 
        o use SysV semaphores or queue of backends waiting on the lock
        o wakeup sleeper or sleep for less than one clock tick 
        o spin for lock on multi-cpu machines, yield on single cpu machines
        o read/write locks

-- 
  Bruce Momjian                        |  http://candle.pha.pa.us
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