Before & After Under The Giant Lock

[Roman Divacky]

On Sun, Nov 25, 2007 at 02:41:35PM -0600, Stephen Montgomery-Smith wrote:
> 
> 
> On Sun, 25 Nov 2007, Robert Watson wrote:
> 
> >........................
> >In FreeBSD 8, I expect we'll see a continued focus on both locking 
> >granularity and improving opportunities for kernel parallelism by better 
> >distributing workloads over CPU pools.  This is important because the 
> >number of cores/chip is continuing to increase dramatically, so MP 
> >performance is going to be important to keep working on.  That said, the 
> >results to date have been extremely promising, and I anticipate that we 
> >will continue to find ways to better exploit multiprocessor hardware, 
> >especially in the network stack.
> >
> 
> I just want to add my 2 cents, that my recent experience with FreeBSD MP 
> has been extremely positive.  I tend to use highly CPU bound MP programs, 
> typically lots and lots of floating point operations.  It used to be that 
> Linux beat FreeBSD hands down - now FreeBSD seems to have a slight edge! 
> Basically my program runs about twice as fast when I run two threads as 
> opposed to one - I cannot see doing any better than that!

pure computation does not need kernel operations most of the time.. ie. 
multi-threading kernel wont help much ;)