From: Jack Steiner Date: Tue, 15 Nov 2011 23:33:56 +0000 (-0800) Subject: x86: Reduce clock calibration time during slave cpu startup X-Git-Tag: v3.3-rc1~93^2~8 X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=b565201cf75210614903ef2ae5917b4379681647;p=pandora-kernel.git x86: Reduce clock calibration time during slave cpu startup Reduce the startup time for slave cpus. Adds hooks for an arch-specific function for clock calibration. These hooks are used on x86. If a newly started cpu has the same phys_proc_id as a core already active, uses the TSC for the delay loop and has a CONSTANT_TSC, use the already-calculated value of loops_per_jiffy. This patch reduces the time required to start slave cpus on a 4096 cpu system from: 465 sec OLD 62 sec NEW This reduces boot time on a 4096p system by almost 7 minutes. Nice... Signed-off-by: Jack Steiner Cc: "H. Peter Anvin" Cc: John Stultz [fix CONFIG_SMP=n build] Signed-off-by: Andrew Morton Signed-off-by: Ingo Molnar --- Reading git-diff-tree failed