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| author | Martin Schwidefsky <schwidefsky@de.ibm.com> | 2009-09-29 14:25:16 +0200 |
|---|---|---|
| committer | Thomas Gleixner <tglx@linutronix.de> | 2009-11-05 07:53:53 +0100 |
| commit | 3c5d92a0cfb5103c0d5ab74d4ae6373d3af38148 (patch) | |
| tree | c8b50351568601428b6f9396ebfdd65e486b3097 /include/linux/tick.h | |
| parent | eed3b9cf3fe3fcc7a50238dfcab63a63914e8f42 (diff) | |
| download | op-kernel-dev-3c5d92a0cfb5103c0d5ab74d4ae6373d3af38148.zip op-kernel-dev-3c5d92a0cfb5103c0d5ab74d4ae6373d3af38148.tar.gz | |
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>
Diffstat (limited to 'include/linux/tick.h')
| -rw-r--r-- | include/linux/tick.h | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/include/linux/tick.h b/include/linux/tick.h index 0482229..8dc0821 100644 --- a/include/linux/tick.h +++ b/include/linux/tick.h @@ -98,6 +98,9 @@ extern int tick_check_oneshot_change(int allow_nohz); extern struct tick_sched *tick_get_tick_sched(int cpu); extern void tick_check_idle(int cpu); extern int tick_oneshot_mode_active(void); +# ifndef arch_needs_cpu +# define arch_needs_cpu(cpu) (0) +# endif # else static inline void tick_clock_notify(void) { } static inline int tick_check_oneshot_change(int allow_nohz) { return 0; } |
