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powerpc/pseries: Do not start secondaries in Open Firmware

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Starting secondary CPUs early on from Open Firmware and placing them
in a holding spin loop slows down the boot process significantly under
some hypervisors such as KVM.

This is also unnecessary when RTAS supports querying the CPU state

So let's not do it.

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
This commit is contained in:
Benjamin Herrenschmidt
2013-09-25 14:02:50 +10:00
parent 0c9fa29149
commit dbe78b4011
2 changed files with 37 additions and 10 deletions
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26
arch/powerpc/platforms/pseries/smp.c
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@@ -233,17 +233,23 @@ static void __init smp_init_pseries(void)
alloc_bootmem_cpumask_var(&of_spin_mask);
/* Mark threads which are still spinning in hold loops. */
if (cpu_has_feature(CPU_FTR_SMT)) {
for_each_present_cpu(i) {
if (cpu_thread_in_core(i) == 0)
cpumask_set_cpu(i, of_spin_mask);
}
} else {
cpumask_copy(of_spin_mask, cpu_present_mask);
}
/*
* Mark threads which are still spinning in hold loops
*
* We know prom_init will not have started them if RTAS supports
* query-cpu-stopped-state.
*/
if (rtas_token("query-cpu-stopped-state") == RTAS_UNKNOWN_SERVICE) {
if (cpu_has_feature(CPU_FTR_SMT)) {
for_each_present_cpu(i) {
if (cpu_thread_in_core(i) == 0)
cpumask_set_cpu(i, of_spin_mask);
}
} else
cpumask_copy(of_spin_mask, cpu_present_mask);
cpumask_clear_cpu(boot_cpuid, of_spin_mask);
cpumask_clear_cpu(boot_cpuid, of_spin_mask);
}
/* Non-lpar has additional take/give timebase */
if (rtas_token("freeze-time-base") != RTAS_UNKNOWN_SERVICE) {