[PATCH] x86, UV: Remove UV delay in starting slave cpus

[PATCH] x86, UV: Remove UV delay in starting slave cpus

[Jack Steiner]

Delete the 10 msec delay between the INIT and SIPI when starting slave
cpus. I can find no requirement for this delay. BIOS also has similar code
sequences without the delay.

Removing the delay reduces boot time by 40 sec. Every bit helps.

Signed-off-by: Jack Steiner <steiner@sgi.com>


---
 arch/x86/kernel/apic/x2apic_uv_x.c |    1 -
 1 file changed, 1 deletion(-)

Index: linux/arch/x86/kernel/apic/x2apic_uv_x.c
===================================================================
--- linux.orig/arch/x86/kernel/apic/x2apic_uv_x.c	2011-08-05 08:22:42.511980932 -0500
+++ linux/arch/x86/kernel/apic/x2apic_uv_x.c	2011-08-05 08:23:27.488613896 -0500
@@ -207,7 +207,6 @@ static int __cpuinit uv_wakeup_secondary
 	    ((start_rip << UVH_IPI_INT_VECTOR_SHFT) >> 12) |
 	    APIC_DM_INIT;
 	uv_write_global_mmr64(pnode, UVH_IPI_INT, val);
-	mdelay(10);
 
 	val = (1UL << UVH_IPI_INT_SEND_SHFT) |
 	    (phys_apicid << UVH_IPI_INT_APIC_ID_SHFT) |

[tip:x86/urgent] x86, UV: Remove UV delay in starting slave cpus

[tip-bot for Jack Steiner]

Commit-ID:  05e33fc20ea5e493a2a1e7f1d04f43cdf89f83ed
Gitweb:     http://git.kernel.org/tip/05e33fc20ea5e493a2a1e7f1d04f43cdf89f83ed
Author:     Jack Steiner <steiner@sgi.com>
AuthorDate: Fri, 5 Aug 2011 09:09:00 -0500
Committer:  Ingo Molnar <mingo@elte.hu>
CommitDate: Fri, 5 Aug 2011 23:48:34 +0200

x86, UV: Remove UV delay in starting slave cpus

Delete the 10 msec delay between the INIT and SIPI when starting
slave cpus. I can find no requirement for this delay. BIOS also
has similar code sequences without the delay.

Removing the delay reduces boot time by 40 sec. Every bit helps.

Signed-off-by: Jack Steiner <steiner@sgi.com>
Cc: <stable@kernel.org>
Link: http://lkml.kernel.org/r/20110805140900.GA6774@sgi.com
Signed-off-by: Ingo Molnar <mingo@elte.hu>
---
 arch/x86/kernel/apic/x2apic_uv_x.c |    1 -
 1 files changed, 0 insertions(+), 1 deletions(-)

diff --git a/arch/x86/kernel/apic/x2apic_uv_x.c b/arch/x86/kernel/apic/x2apic_uv_x.c
index adc66c3..34b1859 100644
--- a/arch/x86/kernel/apic/x2apic_uv_x.c
+++ b/arch/x86/kernel/apic/x2apic_uv_x.c
@@ -207,7 +207,6 @@ static int __cpuinit uv_wakeup_secondary(int phys_apicid, unsigned long start_ri
 	    ((start_rip << UVH_IPI_INT_VECTOR_SHFT) >> 12) |
 	    APIC_DM_INIT;
 	uv_write_global_mmr64(pnode, UVH_IPI_INT, val);
-	mdelay(10);
 
 	val = (1UL << UVH_IPI_INT_SEND_SHFT) |
 	    (phys_apicid << UVH_IPI_INT_APIC_ID_SHFT) |