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[IA64] add missing cpu_relax() in ITC syncing code 

Call cpu_relax() in busy-waiting loops of the ITC-syncing code.

Signed-off-by: David Mosberger-Tang <davidm@hpl.hp.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>
This commit is contained in:
David Mosberger-Tang 2005-04-25 11:44:02 -07:00 committed by Tony Luck
parent bf1cf98fa9
commit 8297511530
1 changed files with 7 additions and 4 deletions
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11
arch/ia64/kernel/smpboot.c
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@ -1,7 +1,7 @@
/* /*
* SMP boot-related support * SMP boot-related support
* *
* Copyright (C) 1998-2003 Hewlett-Packard Co * Copyright (C) 1998-2003, 2005 Hewlett-Packard Co
* David Mosberger-Tang <davidm@hpl.hp.com> * David Mosberger-Tang <davidm@hpl.hp.com>
* *
* 01/05/16 Rohit Seth <rohit.seth@intel.com> Moved SMP booting functions from smp.c to here. * 01/05/16 Rohit Seth <rohit.seth@intel.com> Moved SMP booting functions from smp.c to here.
@ -156,7 +156,8 @@ sync_master (void *arg)
local_irq_save(flags); local_irq_save(flags);
{ {
for (i = 0; i < NUM_ROUNDS*NUM_ITERS; ++i) { for (i = 0; i < NUM_ROUNDS*NUM_ITERS; ++i) {
while (!go[MASTER]); while (!go[MASTER])
cpu_relax();
go[MASTER] = 0; go[MASTER] = 0;
go[SLAVE] = ia64_get_itc(); go[SLAVE] = ia64_get_itc();
} }
@ -179,7 +180,8 @@ get_delta (long *rt, long *master)
for (i = 0; i < NUM_ITERS; ++i) { for (i = 0; i < NUM_ITERS; ++i) {
t0 = ia64_get_itc(); t0 = ia64_get_itc();
go[MASTER] = 1; go[MASTER] = 1;
while (!(tm = go[SLAVE])); while (!(tm = go[SLAVE]))
cpu_relax();
go[SLAVE] = 0; go[SLAVE] = 0;
t1 = ia64_get_itc(); t1 = ia64_get_itc();
@ -258,7 +260,8 @@ ia64_sync_itc (unsigned int master)
return; 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); spin_lock_irqsave(&itc_sync_lock, flags);
{ {