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authorVince Weaver <vincent.weaver@maine.edu>2012-10-17 21:05:45 +0400
committerIngo Molnar <mingo@kernel.org>2012-10-24 14:00:49 +0400
commite4074b3049f99c6ad6e1a33e6d93d8ec0652e2c1 (patch)
tree7e2710993db62f28f25b153a345a5ded68e67bd6 /arch/x86
parent7d011962afbaa6e572cd8e0dbb7abf773e166e64 (diff)
downloadlinux-e4074b3049f99c6ad6e1a33e6d93d8ec0652e2c1.tar.xz
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 <vincent.weaver@maine.edu> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Paul Mackerras <paulus@samba.org> Cc: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Cc: eranian@gmail.com Cc: Meadows Lawrence F <lawrence.f.meadows@intel.com> 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 <mingo@kernel.org>
Diffstat (limited to 'arch/x86')
-rw-r--r--arch/x86/kernel/cpu/perf_event_knc.c78
1 files changed, 77 insertions, 1 deletions
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 <linux/perf_event.h>
#include <linux/types.h>
+#include <asm/hardirq.h>
+
#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,