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authorSrivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com>2014-02-26 05:37:43 +0530
committerBenjamin Herrenschmidt <benh@kernel.crashing.org>2014-03-05 15:55:04 +1100
commit1b67bee129a36c22c17186cc2a9981678e9323ee (patch)
treeaf3787d56f78a8f4624aabb7771589deb1428192 /arch/powerpc/kernel/time.c
parent402d9a1e02f7215628f13b7c80ff3e98c3a0cadc (diff)
downloadop-kernel-dev-1b67bee129a36c22c17186cc2a9981678e9323ee.zip
op-kernel-dev-1b67bee129a36c22c17186cc2a9981678e9323ee.tar.gz
powerpc: Implement tick broadcast IPI as a fixed IPI message
For scalability and performance reasons, we want the tick broadcast IPIs to be handled as efficiently as possible. Fixed IPI messages are one of the most efficient mechanisms available - they are faster than the smp_call_function mechanism because the IPI handlers are fixed and hence they don't involve costly operations such as adding IPI handlers to the target CPU's function queue, acquiring locks for synchronization etc. Luckily we have an unused IPI message slot, so use that to implement tick broadcast IPIs efficiently. Signed-off-by: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com> [Functions renamed to tick_broadcast* and Changelog modified by Preeti U. Murthy<preeti@linux.vnet.ibm.com>] Signed-off-by: Preeti U. Murthy <preeti@linux.vnet.ibm.com> Acked-by: Geoff Levand <geoff@infradead.org> [For the PS3 part] Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Diffstat (limited to 'arch/powerpc/kernel/time.c')
-rw-r--r--arch/powerpc/kernel/time.c5
1 files changed, 5 insertions, 0 deletions
diff --git a/arch/powerpc/kernel/time.c b/arch/powerpc/kernel/time.c
index b3dab20..3ff97db 100644
--- a/arch/powerpc/kernel/time.c
+++ b/arch/powerpc/kernel/time.c
@@ -825,6 +825,11 @@ static void decrementer_set_mode(enum clock_event_mode mode,
decrementer_set_next_event(DECREMENTER_MAX, dev);
}
+/* Interrupt handler for the timer broadcast IPI */
+void tick_broadcast_ipi_handler(void)
+{
+}
+
static void register_decrementer_clockevent(int cpu)
{
struct clock_event_device *dec = &per_cpu(decrementers, cpu);
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