On Tue, 03 Apr 2007 09:54:46 -0700 Ulrich Drepper <[EMAIL PROTECTED]> wrote:
> More and more code depends on knowing the number of processors in the > system to efficiently scale the code. E.g., in OpenMP it is used by > default to determine how many threads to create. Creating more threads > than there are processors/cores doesn't make sense. but... It would be a mistake for an application to assume that it is allowed to _use_ all the present CPUs. People can and do run applications within cpusets, and under sched_setaffinity(). So I'd have thought that in general an application should be querying its present affinity mask - something like sched_getaffinity()? That fixes the CPU hotplug issues too, of course. But we discussed this all a couple years back and it was decided that sched_getaffinity() was unsuitable. I remember at the time not really understanding why? - 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/
