On Wed, 02 Mar 2011 22:24:00 -0800, Charles Polisher wrote: > Kwan Lowe wrote: [...] > > You might explore what vmstat says about disk activity during an initial > vs follow-on run. Also, I wonder what "top" shows in the WCHAN and nFLT > columns. The problem is OBE since I added some real processing to the code, and I no longer get the apparent buffering. But please see my new thread: "top and allocation issues". Mike.