Gitweb: http://git.kernel.org/git/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commit;h=b6f6b9...
Commit: b6f6b98a4e91fcf31db7de54c3aa86252fc6fb5f
Parent: cd6f37be7fdc9fea407379745350f6630b9d3cdd
Author: Sonny Rao <sonnyrao@us.ibm.com>
AuthorDate: Sat Jul 12 09:00:26 2008 +1000
Committer: Benjamin Herrenschmidt <benh@kernel.crashing.org>
CommitDate: Tue Jul 15 12:29:28 2008 +1000
powerpc: Don't spin on sync instruction at boot time
Push the sync below the secondary smp init hold loop and comment its purpose.
This should speed up boot by reducing global traffic during the single-threaded
portion of boot.
Signed-off-by: Sonny Rao <sonnyrao@us.ibm.com>
Signed-off-by: Milton Miller <miltonm@bga.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
---
arch/powerpc/kernel/head_64.S | 3 ++-
1 files changed, 2 insertions(+), 1 deletions(-)
diff --git a/arch/powerpc/kernel/head_64.S b/arch/powerpc/kernel/head_64.S
index ecced1e..cc8fb47 100644
--- a/arch/powerpc/kernel/head_64.S
+++ b/arch/powerpc/kernel/head_64.S
@@ -1198,7 +1198,6 @@ _GLOBAL(generic_secondary_smp_init)
3: HMT_LOW
lbz r23,PACAPROCSTART(r13) /* Test if this processor should */
/* start. */
- sync
#ifndef CONFIG_SMP
b 3b /* Never go on non-SMP */
@@ -1206,6 +1205,8 @@ _GLOBAL(generic_secondary_smp_init)
cmpwi 0,r23,0
beq 3b /* Loop until told to go */
+ sync /* order paca.run and cur_cpu_spec */
+
/* See if we need to call a cpu state restore handler */
LOAD_REG_IMMEDIATE(r23, cur_cpu_spec)
ld r23,0(r23)
--
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