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Subject[PATCH] x86: move warning message of polling idle and HT enabled
From: Hiroshi Shimamoto <h-shimamoto@ct.jp.nec.com>
Subject: [PATCH] x86: move warning message of polling idle and HT enabled

This warning 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 message to select_idle_routine().
I also implement this warning on 64-bit kernel and make select_idle_routine()
call after detect_ht() call.

Signed-off-by: Hiroshi Shimamoto <h-shimamoto@ct.jp.nec.com>
---
Ingo, this patch needs Andi's patch;
i386: Move MWAIT idle check to generic CPU
http://lkml.org/lkml/2008/1/2/358
I haven't found it in x86.git tree.
arch/x86/kernel/process_32.c | 18 ++++++++++++------
arch/x86/kernel/process_64.c | 17 ++++++++++++-----
arch/x86/kernel/setup_64.c | 3 ++-
3 files changed, 26 insertions(+), 12 deletions(-)
diff --git a/arch/x86/kernel/process_32.c b/arch/x86/kernel/process_32.c
index 69a69c3..d52c032 100644
--- a/arch/x86/kernel/process_32.c
+++ b/arch/x86/kernel/process_32.c
@@ -287,17 +287,27 @@ static void mwait_idle(void)

void __cpuinit select_idle_routine(const struct cpuinfo_x86 *c)
{
+ 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)) {
- printk("monitor/mwait feature present.\n");
/*
* Skip, if setup has overridden idle.
* One CPU supports mwait => All CPUs supports mwait
*/
if (!pm_idle) {
- printk("using mwait in idle threads.\n");
+ printk(KERN_INFO "using mwait in idle threads.\n");
pm_idle = mwait_idle;
}
}
+ selected = 1;
}

static int __init idle_setup(char *str)
@@ -305,10 +315,6 @@ static int __init idle_setup(char *str)
if (!strcmp(str, "poll")) {
printk("using polling idle threads.\n");
pm_idle = poll_idle;
-#ifdef CONFIG_X86_SMP
- if (smp_num_siblings > 1)
- printk("WARNING: polling idle and HT enabled, performance may degrade.\n");
-#endif
} else if (!strcmp(str, "mwait"))
force_mwait = 1;
else
diff --git a/arch/x86/kernel/process_64.c b/arch/x86/kernel/process_64.c
index 5e12edd..8cff606 100644
--- a/arch/x86/kernel/process_64.c
+++ b/arch/x86/kernel/process_64.c
@@ -282,20 +282,27 @@ static void mwait_idle(void)

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)) {
/*
* 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)
diff --git a/arch/x86/kernel/setup_64.c b/arch/x86/kernel/setup_64.c
index c8dcdd2..8ebf990 100644
--- a/arch/x86/kernel/setup_64.c
+++ b/arch/x86/kernel/setup_64.c
@@ -1067,7 +1067,6 @@ void __cpuinit identify_cpu(struct cpuinfo_x86 *c)
break;
}

- select_idle_routine(c);
detect_ht(c);

/*
@@ -1085,6 +1084,8 @@ void __cpuinit identify_cpu(struct cpuinfo_x86 *c)
#ifdef CONFIG_X86_MCE
mcheck_init(c);
#endif
+ select_idle_routine(c);
+
if (c != &boot_cpu_data)
mtrr_ap_init();
#ifdef CONFIG_NUMA
--
1.5.3.6



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