Messages in this thread | | | Subject | Re: [PATCH V3] Fix Committed_AS underflow | From | Dave Hansen <> | Date | Mon, 20 Apr 2009 09:15:20 -0700 |
| |
On Mon, 2009-04-20 at 10:09 +0100, Eric B Munson wrote: > 1. Change NR_CPUS to min(64, NR_CPUS) > This will limit the amount of possible skew on kernels compiled for very > large SMP machines. 64 is an arbitrary number selected to limit the worst > of the skew without using more cache lines. min(64, NR_CPUS) is used > instead of nr_online_cpus() because nr_online_cpus() requires a shared > cache line and a call to hweight to make the calculation. Its runtime > overhead and keeping this counter accurate showed up in profiles and it's > possible that nr_online_cpus() would also show.
-- Dave
| |