From e4074b3049f99c6ad6e1a33e6d93d8ec0652e2c1 Mon Sep 17 00:00:00 2001 From: Vince Weaver Date: Wed, 17 Oct 2012 13:05:45 -0400 Subject: [PATCH] perf/x86: Enable overflow on Intel KNC with a custom knc_pmu_handle_irq() Although based on the Intel P6 design, the interrupt mechnanism for KNC more closely resembles the Intel architectural perfmon one. We can't just re-use that code though, because KNC has different MSR numbers for the status and ack registers. In this case we just cut-and paste from perf_event_intel.c with some minor changes, as it looks like it would not be worth the trouble to change that code to be MSR-configurable. Signed-off-by: Vince Weaver Cc: Peter Zijlstra Cc: Paul Mackerras Cc: Arnaldo Carvalho de Melo Cc: eranian@gmail.com Cc: Meadows Lawrence F Link: http://lkml.kernel.org/r/alpine.DEB.2.02.1210171304410.23243@vincent-weaver-1.um.maine.edu [ Small stylistic edits. ] Signed-off-by: Ingo Molnar --- arch/x86/kernel/cpu/perf_event_knc.c | 78 +++++++++++++++++++++++++++- 1 file changed, 77 insertions(+), 1 deletion(-) diff --git a/arch/x86/kernel/cpu/perf_event_knc.c b/arch/x86/kernel/cpu/perf_event_knc.c index f3a2af41552d..4b7731bf23a8 100644 --- a/arch/x86/kernel/cpu/perf_event_knc.c +++ b/arch/x86/kernel/cpu/perf_event_knc.c @@ -3,6 +3,8 @@ #include #include +#include + #include "perf_event.h" static const u64 knc_perfmon_event_map[] = @@ -193,6 +195,80 @@ static void knc_pmu_enable_event(struct perf_event *event) (void)wrmsrl_safe(hwc->config_base + hwc->idx, val); } +static inline u64 knc_pmu_get_status(void) +{ + u64 status; + + rdmsrl(MSR_KNC_IA32_PERF_GLOBAL_STATUS, status); + + return status; +} + +static inline void knc_pmu_ack_status(u64 ack) +{ + wrmsrl(MSR_KNC_IA32_PERF_GLOBAL_OVF_CONTROL, ack); +} + +static int knc_pmu_handle_irq(struct pt_regs *regs) +{ + struct perf_sample_data data; + struct cpu_hw_events *cpuc; + int handled = 0; + int bit, loops; + u64 status; + + cpuc = &__get_cpu_var(cpu_hw_events); + + knc_pmu_disable_all(); + + status = knc_pmu_get_status(); + if (!status) { + knc_pmu_enable_all(0); + return handled; + } + + loops = 0; +again: + knc_pmu_ack_status(status); + if (++loops > 100) { + WARN_ONCE(1, "perf: irq loop stuck!\n"); + perf_event_print_debug(); + goto done; + } + + inc_irq_stat(apic_perf_irqs); + + for_each_set_bit(bit, (unsigned long *)&status, X86_PMC_IDX_MAX) { + struct perf_event *event = cpuc->events[bit]; + + handled++; + + if (!test_bit(bit, cpuc->active_mask)) + continue; + + if (!intel_pmu_save_and_restart(event)) + continue; + + perf_sample_data_init(&data, 0, event->hw.last_period); + + if (perf_event_overflow(event, &data, regs)) + x86_pmu_stop(event, 0); + } + + /* + * Repeat if there is more work to be done: + */ + status = knc_pmu_get_status(); + if (status) + goto again; + +done: + knc_pmu_enable_all(0); + + return handled; +} + + PMU_FORMAT_ATTR(event, "config:0-7" ); PMU_FORMAT_ATTR(umask, "config:8-15" ); PMU_FORMAT_ATTR(edge, "config:18" ); @@ -210,7 +286,7 @@ static struct attribute *intel_knc_formats_attr[] = { static __initconst struct x86_pmu knc_pmu = { .name = "knc", - .handle_irq = x86_pmu_handle_irq, + .handle_irq = knc_pmu_handle_irq, .disable_all = knc_pmu_disable_all, .enable_all = knc_pmu_enable_all, .enable = knc_pmu_enable_event, -- 2.30.2