From: Zachary Amsden Date: Mon, 5 Mar 2007 08:30:35 +0000 (-0800) Subject: [PATCH] vmi: sched clock paravirt op fix X-Git-Tag: v2.6.21-rc3~80 X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=6cb9a8350aee789100a365794272ed20cc8f2401;p=pandora-kernel.git [PATCH] vmi: sched clock paravirt op fix The custom_sched_clock hook is broken. The result from sched_clock needs to be in nanoseconds, not in CPU cycles. The TSC is insufficient for this purpose, because TSC is poorly defined in a virtual environment, and mostly represents real world time instead of scheduled process time (which can be interrupted without notice when a virtual machine is descheduled). To make the scheduler consistent, we must expose a different nature of time, that is scheduled time. So deprecate this custom_sched_clock hack and turn it into a paravirt-op, as it should have been all along. This allows the tsc.c code which converts cycles to nanoseconds to be shared by all paravirt-ops backends. It is unfortunate to add a new paravirt-op, but this is a very distinct abstraction which is clearly different for all virtual machine implementations, and it gets rid of an ugly indirect function which I ashamedly admit I hacked in to try to get this to work earlier, and then even got in the wrong units. Signed-off-by: Zachary Amsden Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- Reading git-diff-tree failed