x86/smpboot: Remove SIPI delays from cpu_up()
x86/smpboot: Remove SIPI delays from cpu_up()

MPS 1.4 example code shows the following required delays during processor
on-lining:

	INIT
	 udelay(10,000)
	SIPI
	 udelay(200)
	SIPI
	 udelay(200) /* Linux actually implements this as udelay(300) */

Linux skips the udelay(10,000) on modern processors.
This patch removes the udelay(200) after each SIPI
on those same processors.

All three legacy delays can be restored by the cmdline
"cpu_init_udelay=10000".

As measured by analyze_suspend.py, this patch speeds
processor resume time on my desktop from 2.4ms to 1.8ms, per AP.

Signed-off-by: Len Brown <b060cfa1096cc6e8be83699ddb4ed8a77dd63af5@intel.com>
Cc: Andy Lutomirski <2cc0d0d76de2e6f37b92deeb83c85cb306fc5dc1@amacapital.net>
Cc: Arjan van de Ven <9043bf4b08f6c93a2cb55d98c3494b123858348f@linux.intel.com>
Cc: Boris Ostrovsky <b41c17b861974b03cec38e3ec2992769b9bfae55@oracle.com>
Cc: Borislav Petkov <0691a664b24b6f15b20cd5aee64b72271db08be1@alien8.de>
Cc: Dave Hansen <71bcd3d88361b22cd828f9a350d19d8775f56d4e@linux.intel.com>
Cc: Igor Mammedov <376726f239c919d31d97c9332191663ab16d47b5@redhat.com>
Cc: Jan H. Schönherr <1efe2936df018d84495bec87c3af247a9b3ee9f2@amazon.de>
Cc: Linus Torvalds <69652caca27c8b940640ad396ab71f93cacec34f@linux-foundation.org>
Cc: Paul E. McKenney <1e0ce936bb9b355d257bf5790d2513c3f28be22b@linux.vnet.ibm.com>
Cc: Peter Zijlstra <3fddac958924aef220f202ca567388ddab3f14a8@infradead.org>
Cc: Thomas Gleixner <00e4cf8f46a57000a44449bf9dd8cbbcc209fd2a@linutronix.de>
Cc: Zhu Guihua <353a5266279d714de7e448f7bfb8ee55549e7a2c@cn.fujitsu.com>
Link: http://lkml.kernel.org/r/a5dfdbc8fbfdd813784da204aad5677fe459ac37.1439739165.git.b060cfa1096cc6e8be83699ddb4ed8a77dd63af5@intel.com
Signed-off-by: Ingo Molnar <9dbbbf0688fedc85ad4da37637f1a64b8c718ee2@kernel.org>

KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs