Re: high sys time, very very slow builds on new 24-core system

[Andrew Doran <ad%netbsd.org@localhost>]

On Fri, Mar 25, 2011 at 12:16:32AM -0700, Erik Fair wrote:

> It will be interesting to see if this class of problem shows up again when
> NetBSD is supported on the UltraSPARC "Niagra" CPUs.

Agree.  Although as it stands 24 cores/threads would be a problem for
sparc64 since it has a single mutex around the pmap.  One of the goals of
the uvmplock branch is to make it very easy to address that problem.

On x86 the majority of lock contention is likely to come from uvm_pageqlock,
v_interlock on libc.so and ld.so, and directory vnode locks for / and /usr
and /usr/lib an so on.  Things like the scheduler and memory allocators and
so on should not pose any problem, unless there is a bug/regression.