tree c8b50351568601428b6f9396ebfdd65e486b3097
parent eed3b9cf3fe3fcc7a50238dfcab63a63914e8f42
author Martin Schwidefsky <schwidefsky@de.ibm.com> 1254227116 +0200
committer Thomas Gleixner <tglx@linutronix.de> 1257404033 +0100

nohz: Introduce arch_needs_cpu

Allow the architecture to request a normal jiffy tick when the system
goes idle and tick_nohz_stop_sched_tick is called . On s390 the hook is
used to prevent the system going fully idle if there has been an
interrupt other than a clock comparator interrupt since the last wakeup.

On s390 the HiperSockets response time for 1 connection ping-pong goes
down from 42 to 34 microseconds. The CPU cost decreases by 27%.

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
LKML-Reference: <20090929122533.402715150@de.ibm.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>