Re: SMP buildworld times / performance tests

[Mike Smith]

> >> Just following on from this, one thing that I can see immediately being 
> >> very important to me at least is a spinlock in the timecounter structure. 
> >> Calcru and various other things call microtime(), and we're going to want 
> >> to lock out updates and parallel accesses to the timecounter.  What 
> >> should we be using for an interrupt-disabling spinlock?
> >
> >Nothing.  Accesses to the timecounter struct are already MP safe and fast.
> >Only the i8254 timecounter hardware currently needs interrupt-disabling,
> >but it is hopefully never used on SMP machines.
> 
> Worse.  It is used by default on SMP machines which don't sport the
> PIIX timecounter.

ie. anything using the PIIX3 or older (think 440FX dual P6 systems, etc.)

-- 
\\ Give a man a fish, and you feed him for a day. \\  Mike Smith
\\ Tell him he should learn how to fish himself,  \\  [EMAIL PROTECTED]
\\ and he'll hate you for a lifetime.             \\  [EMAIL PROTECTED]




To Unsubscribe: send mail to [EMAIL PROTECTED]
with "unsubscribe freebsd-current" in the body of the message