perf, x86: Add hw_watchdog_set_attr() in a sake of nmi-watchdog on P4
Due to restriction and specifics of Netburst PMU we need a separated
event for NMI watchdog. In particular every Netburst event
consumes not just a counter and a config register, but also an
additional ESCR register.
Since ESCR registers are grouped upon counters (i.e. if ESCR is occupied
for some event there is no room for another event to enter until its
released) we need to pick up the "least" used ESCR (or the most available
one) for nmi-watchdog purposes -- so MSR_P4_CRU_ESCR2/3 was chosen.
With this patch nmi-watchdog and perf top should be able to run simultaneously.
Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
CC: Lin Ming <ming.m.lin@intel.com>
CC: Arnaldo Carvalho de Melo <acme@redhat.com>
CC: Frederic Weisbecker <fweisbec@gmail.com>
Tested-and-reviewed-by: Don Zickus <dzickus@redhat.com>
Tested-and-reviewed-by: Stephane Eranian <eranian@google.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/20110623124918.GC13050@sun
Signed-off-by: Ingo Molnar <mingo@elte.hu>
diff --git a/arch/x86/kernel/cpu/perf_event.c b/arch/x86/kernel/cpu/perf_event.c
index 3a0338b..8a57f9a 100644
--- a/arch/x86/kernel/cpu/perf_event.c
+++ b/arch/x86/kernel/cpu/perf_event.c
@@ -233,6 +233,7 @@
void (*enable_all)(int added);
void (*enable)(struct perf_event *);
void (*disable)(struct perf_event *);
+ void (*hw_watchdog_set_attr)(struct perf_event_attr *attr);
int (*hw_config)(struct perf_event *event);
int (*schedule_events)(struct cpu_hw_events *cpuc, int n, int *assign);
unsigned eventsel;
@@ -315,6 +316,12 @@
[PERF_COUNT_HW_CACHE_OP_MAX]
[PERF_COUNT_HW_CACHE_RESULT_MAX];
+void hw_nmi_watchdog_set_attr(struct perf_event_attr *wd_attr)
+{
+ if (x86_pmu.hw_watchdog_set_attr)
+ x86_pmu.hw_watchdog_set_attr(wd_attr);
+}
+
/*
* Propagate event elapsed time into the generic event.
* Can only be executed on the CPU where the event is active.
diff --git a/arch/x86/kernel/cpu/perf_event_p4.c b/arch/x86/kernel/cpu/perf_event_p4.c
index ead584f..f76fddf 100644
--- a/arch/x86/kernel/cpu/perf_event_p4.c
+++ b/arch/x86/kernel/cpu/perf_event_p4.c
@@ -705,6 +705,31 @@
return 0;
}
+static void p4_hw_watchdog_set_attr(struct perf_event_attr *wd_attr)
+{
+ /*
+ * Watchdog ticks are special on Netburst, we use
+ * that named "non-sleeping" ticks as recommended
+ * by Intel SDM Vol3b.
+ */
+ WARN_ON_ONCE(wd_attr->type != PERF_TYPE_HARDWARE ||
+ wd_attr->config != PERF_COUNT_HW_CPU_CYCLES);
+
+ wd_attr->type = PERF_TYPE_RAW;
+ wd_attr->config =
+ p4_config_pack_escr(P4_ESCR_EVENT(P4_EVENT_EXECUTION_EVENT) |
+ P4_ESCR_EMASK_BIT(P4_EVENT_EXECUTION_EVENT, NBOGUS0) |
+ P4_ESCR_EMASK_BIT(P4_EVENT_EXECUTION_EVENT, NBOGUS1) |
+ P4_ESCR_EMASK_BIT(P4_EVENT_EXECUTION_EVENT, NBOGUS2) |
+ P4_ESCR_EMASK_BIT(P4_EVENT_EXECUTION_EVENT, NBOGUS3) |
+ P4_ESCR_EMASK_BIT(P4_EVENT_EXECUTION_EVENT, BOGUS0) |
+ P4_ESCR_EMASK_BIT(P4_EVENT_EXECUTION_EVENT, BOGUS1) |
+ P4_ESCR_EMASK_BIT(P4_EVENT_EXECUTION_EVENT, BOGUS2) |
+ P4_ESCR_EMASK_BIT(P4_EVENT_EXECUTION_EVENT, BOGUS3)) |
+ p4_config_pack_cccr(P4_CCCR_THRESHOLD(15) | P4_CCCR_COMPLEMENT |
+ P4_CCCR_COMPARE);
+}
+
static int p4_hw_config(struct perf_event *event)
{
int cpu = get_cpu();
@@ -1179,6 +1204,7 @@
.cntval_bits = ARCH_P4_CNTRVAL_BITS,
.cntval_mask = ARCH_P4_CNTRVAL_MASK,
.max_period = (1ULL << (ARCH_P4_CNTRVAL_BITS - 1)) - 1,
+ .hw_watchdog_set_attr = p4_hw_watchdog_set_attr,
.hw_config = p4_hw_config,
.schedule_events = p4_pmu_schedule_events,
/*
diff --git a/kernel/watchdog.c b/kernel/watchdog.c
index 3d0c56a..752b75b 100644
--- a/kernel/watchdog.c
+++ b/kernel/watchdog.c
@@ -200,6 +200,8 @@
}
#ifdef CONFIG_HARDLOCKUP_DETECTOR
+void __weak hw_nmi_watchdog_set_attr(struct perf_event_attr *wd_attr) { }
+
static struct perf_event_attr wd_hw_attr = {
.type = PERF_TYPE_HARDWARE,
.config = PERF_COUNT_HW_CPU_CYCLES,
@@ -368,9 +370,11 @@
if (event != NULL)
goto out_enable;
- /* Try to register using hardware perf events */
wd_attr = &wd_hw_attr;
wd_attr->sample_period = hw_nmi_get_sample_period(watchdog_thresh);
+ hw_nmi_watchdog_set_attr(wd_attr);
+
+ /* Try to register using hardware perf events */
event = perf_event_create_kernel_counter(wd_attr, cpu, NULL, watchdog_overflow_callback);
if (!IS_ERR(event)) {
printk(KERN_INFO "NMI watchdog enabled, takes one hw-pmu counter.\n");