Messages in this thread |  | | Date | Mon, 11 Sep 2006 10:37:34 +0200 | From | Nick Piggin <> | Subject | Re: [PATCH] Fix longstanding load balancing bug in the scheduler. |
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On Sat, Sep 09, 2006 at 12:56:16PM -0700, Christoph Lameter wrote: > On Fri, 8 Sep 2006, Christoph Lameter wrote: > > > > one or more, it is unnecessary for the common case. > > > > The common case is an arch with much less cpus. The maxinum on i386 > > f.e. is 255 meaning 8 bytes. That fits in the cacheline that is already > > used for the stack frame of the calling function. > > Ughh. Wrong. 255 cpus require 32 bytes. System rarely have that > much. If you configure a kernel with less than 32 cpus then this will be > one word on the stack. > > Also note that the patch restricts the search to online cpus. The > scheduler will check offline cpus without this patch. That may actually > result in speed improvements since the cachelines from offline cpus are > no longer brought in during the search for the busiest group / cpu.
This should not be the case. The sched-domain structure should always reflect the online CPUs only (see our hotplug cpu handler), and if you find otherwise then that would be a bug.
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