On 29/08/2011 18:24, Brett Glass wrote:
With hyperthreading, the FreeBSD scheduler simply acts as if there are 4 CPUs. Each "CPU" gets clock interrupts (which add overhead), and the scheduler is naive about the fact that two of the "CPUs" are not separate chips and could be held up if its mate has a heavy load. I do not know if the supposed higher utilization of the resources on each chip (including executing one thread while the CPU waits for data for another) is worth it. What has your experience been?
Actually, the ULE scheduler does know about HyperThreading and the topology of such CPUs. I don't know what it does with the information, but it probably works to optimize cache usage etc.
-- Bruce Cran _______________________________________________ freebsd-questions@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to "freebsd-questions-unsubscr...@freebsd.org"
