[patch 04/54] i386: Fix K8/core2 oprofile on multiple CPUs

Chris Wright
2007-06-08T07:35:08Z

[-- Attachment #1: i386-fix-k8-core2-oprofile-on-multiple-cpus.patch --]
[-- Type: text/plain, Size: 1633 bytes --]

-stable review patch. If anyone has any objections, please let us know.
---------------------

From: Andi Kleen <ak@suse.de>

Only try to allocate MSRs once instead of for every CPU.

This assumes the MSRs are the same on all CPUs which is currently
true. P4-HT is a special case for different SMT threads, but the code
always saves/restores all MSRs so it works identical.

Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Chris Wright <chrisw@sous-sol.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
---
arch/i386/oprofile/nmi_int.c | 9 ++++++++-
1 file changed, 8 insertions(+), 1 deletion(-)

--- linux-2.6.21.4.orig/arch/i386/oprofile/nmi_int.c
+++ linux-2.6.21.4/arch/i386/oprofile/nmi_int.c
@@ -131,7 +131,6 @@ static void nmi_save_registers(void * du
{
int cpu = smp_processor_id();
struct op_msrs * msrs = &cpu_msrs[cpu];
- model->fill_in_addresses(msrs);
nmi_cpu_save_registers(msrs);
}

@@ -195,6 +194,7 @@ static struct notifier_block profile_exc
static int nmi_setup(void)
{
int err=0;
+ int cpu;

if (!allocate_msrs())
return -ENOMEM;
@@ -207,6 +207,13 @@ static int nmi_setup(void)
/* We need to serialize save and setup for HT because the subset
* of msrs are distinct for save and setup operations
*/
+
+ /* Assume saved/restored counters are the same on all CPUs */
+ model->fill_in_addresses(&cpu_msrs[0]);
+ for_each_possible_cpu (cpu) {
+ if (cpu != 0)
+ cpu_msrs[cpu] = cpu_msrs[0];
+ }
on_each_cpu(nmi_save_registers, NULL, 0, 1);
on_each_cpu(nmi_cpu_setup, NULL, 0, 1);
nmi_enabled = 1;

--