Re: oprofile: enabling cpu events

[Baruch Even <baruch@ev-en.org>]

li nux wrote:
> I want to profile cpu events using oprofile, when i
> issue following command, it gives me an error saying
> that oprofile is in timer mode.
> What does it mean ?
> the link
> http://oprofile.sourceforge.net/docs/intel-piii-events.php3
> says event=CPU_CLK_UNHALTED is suppported for Pentium
> II processor.
>
> Is there any way i can enable cpu events ?
>
> # opcontrol --setup  --event=CPU_CLK_UNHALTED
> You cannot specify any performance counter events
> because OProfile is in timer mode.

The code has some "protection" against too new processors, the kernel 
folks prefer that you use older CPUs, or use newer kernels.

The patch that worked for me against 2.6.6 is attached.

Baruch

 arch/i386/oprofile/nmi_int.c |    2 +-
 1 files changed, 1 insertion(+), 1 deletion(-)

Index: 2.6.6/arch/i386/oprofile/nmi_int.c
===================================================================
--- 2.6.6.orig/arch/i386/oprofile/nmi_int.c
+++ 2.6.6/arch/i386/oprofile/nmi_int.c
@@ -313,7 +313,7 @@ static int __init p4_init(void)
 {
 	__u8 cpu_model = current_cpu_data.x86_model;
 
-	if (cpu_model > 3)
+	if (cpu_model > 100)
 		return 0;
 
 #ifndef CONFIG_SMP