Commit-ID: f285f92f7e4c9af20149130c8fd5027131b39b0e
Gitweb: http://git.kernel.org/tip/f285f92f7e4c9af20149130c8fd5027131b39b0e
Author: Robert Richter <robert.richter@xxxxxxx>
AuthorDate: Wed, 20 Jun 2012 20:46:36 +0200
Committer: Ingo Molnar <mingo@xxxxxxxxxx>
CommitDate: Thu, 5 Jul 2012 21:19:42 +0200
perf/x86: Improve debug output in check_hw_exists()
It might be of interest which perfctr msr failed.
Signed-off-by: Robert Richter <robert.richter@xxxxxxx>
[ added hunk to avoid GCC warn ]
Signed-off-by: Peter Zijlstra <a.p.zijlstra@xxxxxxxxx>
Link: http://lkml.kernel.org/r/1340217996-2254-5-git-send-email-robert.richter@xxxxxxx
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
---
arch/x86/kernel/cpu/perf_event.c | 8 +++++---
1 files changed, 5 insertions(+), 3 deletions(-)
diff --git a/arch/x86/kernel/cpu/perf_event.c b/arch/x86/kernel/cpu/perf_event.c
index 7b4f1e8..3eb88eb 100644
--- a/arch/x86/kernel/cpu/perf_event.c
+++ b/arch/x86/kernel/cpu/perf_event.c
@@ -178,7 +178,7 @@ static void release_pmc_hardware(void) {}
static bool check_hw_exists(void)
{
- u64 val, val_new = 0;
+ u64 val, val_new = ~0;
int i, reg, ret = 0;
/*
@@ -211,8 +211,9 @@ static bool check_hw_exists(void)
* that don't trap on the MSR access and always return 0s.
*/
val = 0xabcdUL;
- ret = wrmsrl_safe(x86_pmu_event_addr(0), val);
- ret |= rdmsrl_safe(x86_pmu_event_addr(0), &val_new);
+ reg = x86_pmu_event_addr(0);
+ ret = wrmsrl_safe(reg, val);
+ ret |= rdmsrl_safe(reg, &val_new);
if (ret || val != val_new)
goto msr_fail;
@@ -229,6 +230,7 @@ bios_fail:
msr_fail:
printk(KERN_CONT "Broken PMU hardware detected, using software events only.\n");
+ printk(KERN_ERR "Failed to access perfctr msr (MSR %x is %Lx)\n", reg, val_new);
return false;
}
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