Hi Tony,
Attached trivial patch adds 3 cpu_relax() calls in busy-waiting loops.
Please apply.
Thanks,
--david
Call cpu_relax() in busy-waiting loops of the ITC-syncing code.
Signed-off-by: David Mosberger-Tang <[EMAIL PROTECTED]>
===== arch/ia64/kernel/smpboot.c 1.65 vs edited =====
--- 1.65/arch/ia64/kernel/smpboot.c 2005-01-22 13:13:47 -08:00
+++ edited/arch/ia64/kernel/smpboot.c 2005-03-10 22:08:36 -08:00
@@ -1,7 +1,7 @@
/*
* SMP boot-related support
*
- * Copyright (C) 1998-2003 Hewlett-Packard Co
+ * Copyright (C) 1998-2003, 2005 Hewlett-Packard Co
* David Mosberger-Tang <[EMAIL PROTECTED]>
*
* 01/05/16 Rohit Seth <[EMAIL PROTECTED]> Moved SMP booting functions
from smp.c to here.
@@ -124,7 +124,8 @@
local_irq_save(flags);
{
for (i = 0; i < NUM_ROUNDS*NUM_ITERS; ++i) {
- while (!go[MASTER]);
+ while (!go[MASTER])
+ cpu_relax();
go[MASTER] = 0;
go[SLAVE] = ia64_get_itc();
}
@@ -147,7 +148,8 @@
for (i = 0; i < NUM_ITERS; ++i) {
t0 = ia64_get_itc();
go[MASTER] = 1;
- while (!(tm = go[SLAVE]));
+ while (!(tm = go[SLAVE]))
+ cpu_relax();
go[SLAVE] = 0;
t1 = ia64_get_itc();
@@ -226,7 +228,8 @@
return;
}
- while (go[MASTER]); /* wait for master to be ready */
+ while (go[MASTER])
+ cpu_relax(); /* wait for master to be ready */
spin_lock_irqsave(&itc_sync_lock, flags);
{
-
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