[28/35] x86, UV: Remove UV delay in starting slave cpus

From: Greg KH
Date: Sat Aug 27 2011 - 10:59:01 EST


3.0-stable review patch. If anyone has any objections, please let us know.

------------------

From: Jack Steiner <steiner@xxxxxxx>

commit 05e33fc20ea5e493a2a1e7f1d04f43cdf89f83ed upstream.

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@xxxxxxx>
Link: http://lkml.kernel.org/r/20110805140900.GA6774@xxxxxxx
Signed-off-by: Ingo Molnar <mingo@xxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxx>

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

--- 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
((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) |


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