On Tue, Feb 15, 2011 at 20:01, Scott Marlowe <scott.marlowe@gmail.com> wrote:
> run htop and look for red. if youi've got lots of red bar on each CPU
> but no io wait then it's waiting for memory access.
I don't think this is true. AFAICT the red bar refers to "system
time", time that's spent in the kernel -- either in syscalls or kernel
background threads.
Operating systems don't generally account memory accesses (cache
misses) for processes, if you don't specially ask for it. The closest
thing I know of is using Linux perf tools, e.g. "perf top -e
cache-misses". OProfile, DTrace and SystemTap can probably do
something similar.
Regards,
Marti
