Subject: Re: Lock benchmarks
To: Jason R Thorpe <firstname.lastname@example.org>
From: Gregory McGarry <email@example.com>
Date: 09/19/2002 08:33:18
Jason R Thorpe wrote:
> > The assembler routines will be the ones used in the pthread library
> > if it is decided that RAS locks should be used by default on
> > uniprocessor machines. I guess the jury is still out on that one.
> I have some comments on the asm:
> 1. In a RAS locking scheme, you only ever want to provide
> or use the "lock_try" version. This is because if the
> lock is held, know either: (a) you need to context
> switch, (b) you need to croak (deadlock). If you spin
> around, then you're just consuming cpu time, and might
> deadlock if your threads aren't being timesliced against
> each other.
Yep. And the pthread library currently works like that.
-- Gregory McGarry <firstname.lastname@example.org>