From 1dcdb5a9e7c235e6e80f1f4d5b8247b3e5347e48 Mon Sep 17 00:00:00 2001
From: Andi Kleen <andi@firstfloor.org>
Date: Mon, 27 Apr 2009 17:44:11 +0200
Subject: [PATCH] oprofile: re-add force_arch_perfmon option
This re-adds the force_arch_perfmon option that was in the original
arch perfmon patchkit. Originally this was rejected in favour
of a generalized perfmon=name option, but it turned out implementing
the later in a reliable way is hard (and it would have been easy
to crash the kernel if a user gets it wrong)
But now Atom and Core i7 support being readded a user would
need to update their oprofile userland to beyond 0.9.4 to use oprofile again
on Atom or Core i7.
To avoid this problem readd the force_arch_perfmon option.
Signed-off-by: Andi Kleen <ak@linux.intel.com>
Signed-off-by: Robert Richter <robert.richter@amd.com>
---
Documentation/kernel-parameters.txt | 6 ++++++
arch/x86/oprofile/nmi_int.c | 6 ++++++
2 files changed, 12 insertions(+)
diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index 90b3924071b6c..9b9566bf3301f 100644
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -1650,6 +1650,12 @@ and is between 256 and 4096 characters. It is defined in the file
oprofile.timer= [HW]
Use timer interrupt instead of performance counters
+ oprofile.force_arch_perfmon=1 [X86]
+ Force use of architectural perfmon instead of
+ the CPU specific event set.
+ This might be useful if you have older oprofile
+ userland or if you want common events over Intel CPUs.
+
osst= [HW,SCSI] SCSI Tape Driver
Format: <buffer_size>,<write_threshold>
See also Documentation/scsi/st.txt.
diff --git a/arch/x86/oprofile/nmi_int.c b/arch/x86/oprofile/nmi_int.c
index 202864ad49a7e..e5171c99e1576 100644
--- a/arch/x86/oprofile/nmi_int.c
+++ b/arch/x86/oprofile/nmi_int.c
@@ -389,10 +389,16 @@ static int __init p4_init(char **cpu_type)
return 0;
}
+int force_arch_perfmon;
+module_param(force_arch_perfmon, int, 0);
+
static int __init ppro_init(char **cpu_type)
{
__u8 cpu_model = boot_cpu_data.x86_model;
+ if (force_arch_perfmon && cpu_has_arch_perfmon)
+ return 0;
+
switch (cpu_model) {
case 0 ... 2:
*cpu_type = "i386/ppro";
--
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