On 06/13/2010 06:03 PM, Avi Kivity wrote:
Currently fpu management is only lazy in one direction. When we switch into a task, we may avoid loading the fpu state in the hope that the task will never use it. If we guess right we save an fpu load/save cycle; if not, a Device not Available exception will remind us to load the fpu. However, in the other direction, fpu management is eager. When we switch out of an fpu-using task, we always save its fpu state. This is wasteful if the task(s) that run until we switch back in all don't use the fpu, since we could have kept the task's fpu on the cpu all this time and saved an fpu save/load cycle. This can be quite common with threaded interrupts, but will also happen with normal kernel threads and even normal user tasks. This patch series converts task fpu management to be fully lazy. When switching out of a task, we keep its fpu state on the cpu, only flushing it if some other task needs the fpu.
Ingo, Peter, any feedback on this? -- error compiling committee.c: too many arguments to function -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
