Oprofile : need to adjust PC by 16 bytes

[Eric Dumazet]

Very strange results on my Intel E5450 CPU

I found that I have to bias regs->ip by 16 bytes in order to have
correct profiling.

Does it rings a bell to anyone ?

opcontrol --version
opcontrol: oprofile 0.9.4 compiled on Nov  3 2008 06:45:57

Thank you

diff --git a/arch/x86/oprofile/op_model_ppro.c b/arch/x86/oprofile/op_model_ppro.c
index 3f1b81a..051fb16 100644
--- a/arch/x86/oprofile/op_model_ppro.c
+++ b/arch/x86/oprofile/op_model_ppro.c
@@ -131,7 +131,9 @@ static int ppro_check_ctrs(struct pt_regs * const regs,
                       continue;
               rdmsrl(msrs->counters[i].addr, val);
               if (CTR_OVERFLOWED(val)) {
+                       regs->ip -= 0x10;
                       oprofile_add_sample(regs, i);
+                       regs->ip += 0x10;
                       wrmsrl(msrs->counters[i].addr, -reset_value[i]);
               }
       }

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