On Thu, Nov 15, 2007 at 12:07:47PM -0800, Christoph Lameter wrote: > On Thu, 15 Nov 2007, Micah Dowty wrote: > > > For reference, the exact test I used with git-bisect is attached. The > > C program (priosched) starts two busy-looping threads and a > > high-priority high-frequency thread which uses relatively little > > CPU. The Python program repeatedly starts the C program, runs it for a > > half second, and measures the resulting imbalance in CPU usage. On > > kernels prior to the above commit, this reports values within about > > 10% of 1.0. On later kernels, it crashes within a couple iterations > > due to a divide-by-zero error :) > > The kernel crashes? Sounds like your application crashes with a divide by > zero?
Yes, the Python test harness crashes, not the kernel. It's just because on a kernel which exhibits this SMP balancer bug, within a couple of test iterations I'll hit a case where cpu1 was almost totally idle and the test harness divides by zero when calculating the imbalance. --Micah - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
