[tip:perf/pebs] perf, x86: Disable PEBS on clovertown chips
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From: tip-bot for Peter Zijlstra on 10 Mar 2010 08:30 Commit-ID: 3c44780b220e876b01e39d4028cd6f4205fbf5d6 Gitweb: http://git.kernel.org/tip/3c44780b220e876b01e39d4028cd6f4205fbf5d6 Author: Peter Zijlstra <a.p.zijlstra(a)chello.nl> AuthorDate: Thu, 4 Mar 2010 21:49:01 +0100 Committer: Ingo Molnar <mingo(a)elte.hu> CommitDate: Wed, 10 Mar 2010 13:23:35 +0100 perf, x86: Disable PEBS on clovertown chips This CPU has just too many handycaps to be really useful. Signed-off-by: Peter Zijlstra <a.p.zijlstra(a)chello.nl> Cc: Arnaldo Carvalho de Melo <acme(a)infradead.org> Cc: paulus(a)samba.org Cc: eranian(a)google.com Cc: robert.richter(a)amd.com Cc: fweisbec(a)gmail.com LKML-Reference: <20100305154128.890278662(a)chello.nl> Signed-off-by: Ingo Molnar <mingo(a)elte.hu> --- arch/x86/kernel/cpu/perf_event.c | 4 ++++ arch/x86/kernel/cpu/perf_event_intel.c | 27 +++++++++++++++++++++++++++ 2 files changed, 31 insertions(+), 0 deletions(-) diff --git a/arch/x86/kernel/cpu/perf_event.c b/arch/x86/kernel/cpu/perf_event.c index 7b5430b..335ee1d 100644 --- a/arch/x86/kernel/cpu/perf_event.c +++ b/arch/x86/kernel/cpu/perf_event.c @@ -197,6 +197,7 @@ struct x86_pmu { void (*put_event_constraints)(struct cpu_hw_events *cpuc, struct perf_event *event); struct event_constraint *event_constraints; + void (*quirks)(void); void (*cpu_prepare)(int cpu); void (*cpu_starting)(int cpu); @@ -1373,6 +1374,9 @@ void __init init_hw_perf_events(void) pr_cont("%s PMU driver.\n", x86_pmu.name); + if (x86_pmu.quirks) + x86_pmu.quirks(); + if (x86_pmu.num_events > X86_PMC_MAX_GENERIC) { WARN(1, KERN_ERR "hw perf events %d > max(%d), clipping!", x86_pmu.num_events, X86_PMC_MAX_GENERIC); diff --git a/arch/x86/kernel/cpu/perf_event_intel.c b/arch/x86/kernel/cpu/perf_event_intel.c index 246c072..224c952 100644 --- a/arch/x86/kernel/cpu/perf_event_intel.c +++ b/arch/x86/kernel/cpu/perf_event_intel.c @@ -792,6 +792,32 @@ static __initconst struct x86_pmu intel_pmu = { .cpu_dying = fini_debug_store_on_cpu, }; +static void intel_clovertown_quirks(void) +{ + /* + * PEBS is unreliable due to: + * + * AJ67 - PEBS may experience CPL leaks + * AJ68 - PEBS PMI may be delayed by one event + * AJ69 - GLOBAL_STATUS[62] will only be set when DEBUGCTL[12] + * AJ106 - FREEZE_LBRS_ON_PMI doesn't work in combination with PEBS + * + * AJ67 could be worked around by restricting the OS/USR flags. + * AJ69 could be worked around by setting PMU_FREEZE_ON_PMI. + * + * AJ106 could possibly be worked around by not allowing LBR + * usage from PEBS, including the fixup. + * AJ68 could possibly be worked around by always programming + * a pebs_event_reset[0] value and coping with the lost events. + * + * But taken together it might just make sense to not enable PEBS on + * these chips. + */ + printk(KERN_WARNING "PEBS disabled due to CPU errata.\n"); + x86_pmu.pebs = 0; + x86_pmu.pebs_constraints = NULL; +} + static __init int intel_pmu_init(void) { union cpuid10_edx edx; @@ -856,6 +882,7 @@ static __init int intel_pmu_init(void) break; case 15: /* original 65 nm celeron/pentium/core2/xeon, "Merom"/"Conroe" */ + x86_pmu.quirks = intel_clovertown_quirks; case 22: /* single-core 65 nm celeron/core2solo "Merom-L"/"Conroe-L" */ case 23: /* current 45 nm celeron/core2/xeon "Penryn"/"Wolfdale" */ case 29: /* six-core 45 nm xeon "Dunnington" */ -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo(a)vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/ |