Messages in this thread Patch in this message | | | Date | Thu, 5 Jul 2012 23:27:46 -0700 | From | tip-bot for Robert Richter <> | Subject | [tip:perf/core] perf/x86: Improve debug output in check_hw_exists( ) |
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Commit-ID: f285f92f7e4c9af20149130c8fd5027131b39b0e Gitweb: http://git.kernel.org/tip/f285f92f7e4c9af20149130c8fd5027131b39b0e Author: Robert Richter <robert.richter@amd.com> AuthorDate: Wed, 20 Jun 2012 20:46:36 +0200 Committer: Ingo Molnar <mingo@kernel.org> 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@amd.com> [ added hunk to avoid GCC warn ] Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Link: http://lkml.kernel.org/r/1340217996-2254-5-git-send-email-robert.richter@amd.com Signed-off-by: Ingo Molnar <mingo@kernel.org> --- 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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