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authorJack Steiner <steiner@sgi.com>2007-03-27 14:30:19 -0500
committerTony Luck <tony.luck@intel.com>2007-03-29 15:17:11 -0700
commitead6caae1e52a982bf09137c9b5382e9e2d52fdb (patch)
tree2aa16852ac080814f7fd1684c57e2cf594fc6ffe /arch/ia64/kernel/smpboot.c
parent83d2cd3de48a7fb73838c45145780cfa9b1f61fd (diff)
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[IA64] Speed up boot - skip unnecessary clock calibration
Skip clock calibration if cpu being brought online is exactly the same speed, stepping, etc., as the previous cpu. This significantly reduces the time to boot very large systems. Signed-off-by: Jack Steiner <steiner@sgi.com> Signed-off-by: Tony Luck <tony.luck@intel.com>
Diffstat (limited to 'arch/ia64/kernel/smpboot.c')
-rw-r--r--arch/ia64/kernel/smpboot.c17
1 files changed, 16 insertions, 1 deletions
diff --git a/arch/ia64/kernel/smpboot.c b/arch/ia64/kernel/smpboot.c
index b21ddecea94..ff7df439da6 100644
--- a/arch/ia64/kernel/smpboot.c
+++ b/arch/ia64/kernel/smpboot.c
@@ -375,6 +375,7 @@ static void __devinit
smp_callin (void)
{
int cpuid, phys_id, itc_master;
+ struct cpuinfo_ia64 *last_cpuinfo, *this_cpuinfo;
extern void ia64_init_itm(void);
extern volatile int time_keeper_id;
@@ -424,7 +425,21 @@ smp_callin (void)
* Get our bogomips.
*/
ia64_init_itm();
- calibrate_delay();
+
+ /*
+ * Delay calibration can be skipped if new processor is identical to the
+ * previous processor.
+ */
+ last_cpuinfo = cpu_data(cpuid - 1);
+ this_cpuinfo = local_cpu_data;
+ if (last_cpuinfo->itc_freq != this_cpuinfo->itc_freq ||
+ last_cpuinfo->proc_freq != this_cpuinfo->proc_freq ||
+ last_cpuinfo->features != this_cpuinfo->features ||
+ last_cpuinfo->revision != this_cpuinfo->revision ||
+ last_cpuinfo->family != this_cpuinfo->family ||
+ last_cpuinfo->archrev != this_cpuinfo->archrev ||
+ last_cpuinfo->model != this_cpuinfo->model)
+ calibrate_delay();
local_cpu_data->loops_per_jiffy = loops_per_jiffy;
#ifdef CONFIG_IA32_SUPPORT