From: Sonny Rao <sonnyrao@us.ibm.com>
To: benh@kernel.crashing.org
Cc: linuxppc-dev@ozlabs.org, sonnyrao@us.ibm.com, paulus@samba.org,
miltonm@bga.com
Subject: [PATCH] powerpc: don't spin on sync
Date: Fri, 11 Jul 2008 18:00:26 -0500 [thread overview]
Message-ID: <20080711230026.GB17878@us.ibm.com> (raw)
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>
--- next.git/arch/powerpc/kernel/head_64.S~orig 2008-07-11 17:28:47.000000000 -0500
+++ next.git/arch/powerpc/kernel/head_64.S 2008-07-11 17:31:50.000000000 -0500
@@ -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)
reply other threads:[~2008-07-11 23:00 UTC|newest]
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