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Diffstat (limited to 'arch/x86/kernel/cpu/perf_event.c')
-rw-r--r--arch/x86/kernel/cpu/perf_event.c83
1 files changed, 62 insertions, 21 deletions
diff --git a/arch/x86/kernel/cpu/perf_event.c b/arch/x86/kernel/cpu/perf_event.c
index 87848ebe2bb7..4f7001f28936 100644
--- a/arch/x86/kernel/cpu/perf_event.c
+++ b/arch/x86/kernel/cpu/perf_event.c
@@ -190,6 +190,7 @@ static bool check_hw_exists(void)
u64 val, val_fail, val_new= ~0;
int i, reg, reg_fail, ret = 0;
int bios_fail = 0;
+ int reg_safe = -1;
/*
* Check to see if the BIOS enabled any of the counters, if so
@@ -204,6 +205,8 @@ static bool check_hw_exists(void)
bios_fail = 1;
val_fail = val;
reg_fail = reg;
+ } else {
+ reg_safe = i;
}
}
@@ -222,11 +225,22 @@ static bool check_hw_exists(void)
}
/*
+ * If all the counters are enabled, the below test will always
+ * fail. The tools will also become useless in this scenario.
+ * Just fail and disable the hardware counters.
+ */
+
+ if (reg_safe == -1) {
+ reg = reg_safe;
+ goto msr_fail;
+ }
+
+ /*
* Read the current value, change it and read it back to see if it
* matches, this is needed to detect certain hardware emulators
* (qemu/kvm) that don't trap on the MSR access and always return 0s.
*/
- reg = x86_pmu_event_addr(0);
+ reg = x86_pmu_event_addr(reg_safe);
if (rdmsrl_safe(reg, &val))
goto msr_fail;
val ^= 0xffffUL;
@@ -611,6 +625,7 @@ struct sched_state {
int event; /* event index */
int counter; /* counter index */
int unassigned; /* number of events to be assigned left */
+ int nr_gp; /* number of GP counters used */
unsigned long used[BITS_TO_LONGS(X86_PMC_IDX_MAX)];
};
@@ -620,27 +635,29 @@ struct sched_state {
struct perf_sched {
int max_weight;
int max_events;
- struct perf_event **events;
- struct sched_state state;
+ int max_gp;
int saved_states;
+ struct event_constraint **constraints;
+ struct sched_state state;
struct sched_state saved[SCHED_STATES_MAX];
};
/*
* Initialize interator that runs through all events and counters.
*/
-static void perf_sched_init(struct perf_sched *sched, struct perf_event **events,
- int num, int wmin, int wmax)
+static void perf_sched_init(struct perf_sched *sched, struct event_constraint **constraints,
+ int num, int wmin, int wmax, int gpmax)
{
int idx;
memset(sched, 0, sizeof(*sched));
sched->max_events = num;
sched->max_weight = wmax;
- sched->events = events;
+ sched->max_gp = gpmax;
+ sched->constraints = constraints;
for (idx = 0; idx < num; idx++) {
- if (events[idx]->hw.constraint->weight == wmin)
+ if (constraints[idx]->weight == wmin)
break;
}
@@ -687,7 +704,7 @@ static bool __perf_sched_find_counter(struct perf_sched *sched)
if (sched->state.event >= sched->max_events)
return false;
- c = sched->events[sched->state.event]->hw.constraint;
+ c = sched->constraints[sched->state.event];
/* Prefer fixed purpose counters */
if (c->idxmsk64 & (~0ULL << INTEL_PMC_IDX_FIXED)) {
idx = INTEL_PMC_IDX_FIXED;
@@ -696,11 +713,16 @@ static bool __perf_sched_find_counter(struct perf_sched *sched)
goto done;
}
}
+
/* Grab the first unused counter starting with idx */
idx = sched->state.counter;
for_each_set_bit_from(idx, c->idxmsk, INTEL_PMC_IDX_FIXED) {
- if (!__test_and_set_bit(idx, sched->state.used))
+ if (!__test_and_set_bit(idx, sched->state.used)) {
+ if (sched->state.nr_gp++ >= sched->max_gp)
+ return false;
+
goto done;
+ }
}
return false;
@@ -745,7 +767,7 @@ static bool perf_sched_next_event(struct perf_sched *sched)
if (sched->state.weight > sched->max_weight)
return false;
}
- c = sched->events[sched->state.event]->hw.constraint;
+ c = sched->constraints[sched->state.event];
} while (c->weight != sched->state.weight);
sched->state.counter = 0; /* start with first counter */
@@ -756,12 +778,12 @@ static bool perf_sched_next_event(struct perf_sched *sched)
/*
* Assign a counter for each event.
*/
-int perf_assign_events(struct perf_event **events, int n,
- int wmin, int wmax, int *assign)
+int perf_assign_events(struct event_constraint **constraints, int n,
+ int wmin, int wmax, int gpmax, int *assign)
{
struct perf_sched sched;
- perf_sched_init(&sched, events, n, wmin, wmax);
+ perf_sched_init(&sched, constraints, n, wmin, wmax, gpmax);
do {
if (!perf_sched_find_counter(&sched))
@@ -788,9 +810,9 @@ int x86_schedule_events(struct cpu_hw_events *cpuc, int n, int *assign)
x86_pmu.start_scheduling(cpuc);
for (i = 0, wmin = X86_PMC_IDX_MAX, wmax = 0; i < n; i++) {
- hwc = &cpuc->event_list[i]->hw;
+ cpuc->event_constraint[i] = NULL;
c = x86_pmu.get_event_constraints(cpuc, i, cpuc->event_list[i]);
- hwc->constraint = c;
+ cpuc->event_constraint[i] = c;
wmin = min(wmin, c->weight);
wmax = max(wmax, c->weight);
@@ -801,7 +823,7 @@ int x86_schedule_events(struct cpu_hw_events *cpuc, int n, int *assign)
*/
for (i = 0; i < n; i++) {
hwc = &cpuc->event_list[i]->hw;
- c = hwc->constraint;
+ c = cpuc->event_constraint[i];
/* never assigned */
if (hwc->idx == -1)
@@ -821,9 +843,26 @@ int x86_schedule_events(struct cpu_hw_events *cpuc, int n, int *assign)
}
/* slow path */
- if (i != n)
- unsched = perf_assign_events(cpuc->event_list, n, wmin,
- wmax, assign);
+ if (i != n) {
+ int gpmax = x86_pmu.num_counters;
+
+ /*
+ * Do not allow scheduling of more than half the available
+ * generic counters.
+ *
+ * This helps avoid counter starvation of sibling thread by
+ * ensuring at most half the counters cannot be in exclusive
+ * mode. There is no designated counters for the limits. Any
+ * N/2 counters can be used. This helps with events with
+ * specific counter constraints.
+ */
+ if (is_ht_workaround_enabled() && !cpuc->is_fake &&
+ READ_ONCE(cpuc->excl_cntrs->exclusive_present))
+ gpmax /= 2;
+
+ unsched = perf_assign_events(cpuc->event_constraint, n, wmin,
+ wmax, gpmax, assign);
+ }
/*
* In case of success (unsched = 0), mark events as committed,
@@ -840,7 +879,7 @@ int x86_schedule_events(struct cpu_hw_events *cpuc, int n, int *assign)
e = cpuc->event_list[i];
e->hw.flags |= PERF_X86_EVENT_COMMITTED;
if (x86_pmu.commit_scheduling)
- x86_pmu.commit_scheduling(cpuc, e, assign[i]);
+ x86_pmu.commit_scheduling(cpuc, i, assign[i]);
}
}
@@ -1292,8 +1331,10 @@ static void x86_pmu_del(struct perf_event *event, int flags)
x86_pmu.put_event_constraints(cpuc, event);
/* Delete the array entry. */
- while (++i < cpuc->n_events)
+ while (++i < cpuc->n_events) {
cpuc->event_list[i-1] = cpuc->event_list[i];
+ cpuc->event_constraint[i-1] = cpuc->event_constraint[i];
+ }
--cpuc->n_events;
perf_event_update_userpage(event);
generated by cgit v1.2.3-55-g7522 (git 2.39.0) at 2024-07-09 07:29:04 +0200