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[IA64] Speed up boot - skip unnecessary clock calibration

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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>
This commit is contained in:
Jack Steiner 2007-03-27 14:30:19 -05:00 committed by Tony Luck
parent 83d2cd3de4
commit ead6caae1e
1 changed files with 16 additions and 1 deletions
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17
arch/ia64/kernel/smpboot.c
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@ -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