* [PATCH] Add cpu_relax in idle spin loop for no-hlt kernel option
@ 2004-12-04 0:18 Fenghua Yu
0 siblings, 0 replies; only message in thread
From: Fenghua Yu @ 2004-12-04 0:18 UTC (permalink / raw)
To: linux-kernel
If given no-hlt kernel option, ia32 idle loop turns out to be a spin loop.
Add cpu_relax() in this spin loop because IA32 SDM recommends that a PAUSE
instruction be put in all spin loops.
The patch is against 2.6.9 kernel.
Signed-off-by: Fenghua Yu <fenghua.yu@intel.com>
diff -Nurp a/arch/i386/kernel/process.c b/arch/i386/kernel/process.c
--- a/arch/i386/kernel/process.c 2004-10-18 14:53:05.000000000 -0700
+++ b/arch/i386/kernel/process.c 2004-12-02 18:04:43.000000000 -0800
@@ -97,6 +97,8 @@ void default_idle(void)
else
local_irq_enable();
}
+ else
+ cpu_relax();
}
/*
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2004-12-04 0:18 [PATCH] Add cpu_relax in idle spin loop for no-hlt kernel option Fenghua Yu
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