x86: move warning message of polling idle and HT enabled
The warning message at idle_setup() is never shown because
smp_num_sibling hasn't been updated at this point yet.
Move this polling idle and HT enabled warning to select_idle_routine().
I also implement this warning on 64-bit kernel.
Signed-off-by: Hiroshi Shimamoto <h-shimamoto@ct.jp.nec.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
diff --git a/arch/x86/kernel/process_64.c b/arch/x86/kernel/process_64.c
index dbe0a84..9531353 100644
--- a/arch/x86/kernel/process_64.c
+++ b/arch/x86/kernel/process_64.c
@@ -291,20 +291,27 @@
void __cpuinit select_idle_routine(const struct cpuinfo_x86 *c)
{
- static int printed;
+ static int selected;
+
+ if (selected)
+ return;
+#ifdef CONFIG_X86_SMP
+ if (pm_idle == poll_idle && smp_num_siblings > 1) {
+ printk(KERN_WARNING "WARNING: polling idle and HT enabled,"
+ " performance may degrade.\n");
+ }
+#endif
if (cpu_has(c, X86_FEATURE_MWAIT) && mwait_usable(c)) {
/*
* Skip, if setup has overridden idle.
* One CPU supports mwait => All CPUs supports mwait
*/
if (!pm_idle) {
- if (!printed) {
- printk(KERN_INFO "using mwait in idle threads.\n");
- printed = 1;
- }
+ printk(KERN_INFO "using mwait in idle threads.\n");
pm_idle = mwait_idle;
}
}
+ selected = 1;
}
static int __init idle_setup(char *str)