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Diffstat (limited to 'arch/x86/events/intel/lbr.c')
-rw-r--r--arch/x86/events/intel/lbr.c56
1 files changed, 49 insertions, 7 deletions
diff --git a/arch/x86/events/intel/lbr.c b/arch/x86/events/intel/lbr.c
index cf372b90557e..f3e006bed9a7 100644
--- a/arch/x86/events/intel/lbr.c
+++ b/arch/x86/events/intel/lbr.c
@@ -216,6 +216,8 @@ static void intel_pmu_lbr_reset_64(void)
void intel_pmu_lbr_reset(void)
{
+ struct cpu_hw_events *cpuc = this_cpu_ptr(&cpu_hw_events);
+
if (!x86_pmu.lbr_nr)
return;
@@ -223,6 +225,9 @@ void intel_pmu_lbr_reset(void)
intel_pmu_lbr_reset_32();
else
intel_pmu_lbr_reset_64();
+
+ cpuc->last_task_ctx = NULL;
+ cpuc->last_log_id = 0;
}
/*
@@ -334,6 +339,7 @@ static inline u64 rdlbr_to(unsigned int idx)
static void __intel_pmu_lbr_restore(struct x86_perf_task_context *task_ctx)
{
+ struct cpu_hw_events *cpuc = this_cpu_ptr(&cpu_hw_events);
int i;
unsigned lbr_idx, mask;
u64 tos;
@@ -344,9 +350,21 @@ static void __intel_pmu_lbr_restore(struct x86_perf_task_context *task_ctx)
return;
}
- mask = x86_pmu.lbr_nr - 1;
tos = task_ctx->tos;
- for (i = 0; i < tos; i++) {
+ /*
+ * Does not restore the LBR registers, if
+ * - No one else touched them, and
+ * - Did not enter C6
+ */
+ if ((task_ctx == cpuc->last_task_ctx) &&
+ (task_ctx->log_id == cpuc->last_log_id) &&
+ rdlbr_from(tos)) {
+ task_ctx->lbr_stack_state = LBR_NONE;
+ return;
+ }
+
+ mask = x86_pmu.lbr_nr - 1;
+ for (i = 0; i < task_ctx->valid_lbrs; i++) {
lbr_idx = (tos - i) & mask;
wrlbr_from(lbr_idx, task_ctx->lbr_from[i]);
wrlbr_to (lbr_idx, task_ctx->lbr_to[i]);
@@ -354,14 +372,24 @@ static void __intel_pmu_lbr_restore(struct x86_perf_task_context *task_ctx)
if (x86_pmu.intel_cap.lbr_format == LBR_FORMAT_INFO)
wrmsrl(MSR_LBR_INFO_0 + lbr_idx, task_ctx->lbr_info[i]);
}
+
+ for (; i < x86_pmu.lbr_nr; i++) {
+ lbr_idx = (tos - i) & mask;
+ wrlbr_from(lbr_idx, 0);
+ wrlbr_to(lbr_idx, 0);
+ if (x86_pmu.intel_cap.lbr_format == LBR_FORMAT_INFO)
+ wrmsrl(MSR_LBR_INFO_0 + lbr_idx, 0);
+ }
+
wrmsrl(x86_pmu.lbr_tos, tos);
task_ctx->lbr_stack_state = LBR_NONE;
}
static void __intel_pmu_lbr_save(struct x86_perf_task_context *task_ctx)
{
+ struct cpu_hw_events *cpuc = this_cpu_ptr(&cpu_hw_events);
unsigned lbr_idx, mask;
- u64 tos;
+ u64 tos, from;
int i;
if (task_ctx->lbr_callstack_users == 0) {
@@ -371,15 +399,22 @@ static void __intel_pmu_lbr_save(struct x86_perf_task_context *task_ctx)
mask = x86_pmu.lbr_nr - 1;
tos = intel_pmu_lbr_tos();
- for (i = 0; i < tos; i++) {
+ for (i = 0; i < x86_pmu.lbr_nr; i++) {
lbr_idx = (tos - i) & mask;
- task_ctx->lbr_from[i] = rdlbr_from(lbr_idx);
+ from = rdlbr_from(lbr_idx);
+ if (!from)
+ break;
+ task_ctx->lbr_from[i] = from;
task_ctx->lbr_to[i] = rdlbr_to(lbr_idx);
if (x86_pmu.intel_cap.lbr_format == LBR_FORMAT_INFO)
rdmsrl(MSR_LBR_INFO_0 + lbr_idx, task_ctx->lbr_info[i]);
}
+ task_ctx->valid_lbrs = i;
task_ctx->tos = tos;
task_ctx->lbr_stack_state = LBR_VALID;
+
+ cpuc->last_task_ctx = task_ctx;
+ cpuc->last_log_id = ++task_ctx->log_id;
}
void intel_pmu_lbr_sched_task(struct perf_event_context *ctx, bool sched_in)
@@ -531,7 +566,7 @@ static void intel_pmu_lbr_read_32(struct cpu_hw_events *cpuc)
*/
static void intel_pmu_lbr_read_64(struct cpu_hw_events *cpuc)
{
- bool need_info = false;
+ bool need_info = false, call_stack = false;
unsigned long mask = x86_pmu.lbr_nr - 1;
int lbr_format = x86_pmu.intel_cap.lbr_format;
u64 tos = intel_pmu_lbr_tos();
@@ -542,7 +577,7 @@ static void intel_pmu_lbr_read_64(struct cpu_hw_events *cpuc)
if (cpuc->lbr_sel) {
need_info = !(cpuc->lbr_sel->config & LBR_NO_INFO);
if (cpuc->lbr_sel->config & LBR_CALL_STACK)
- num = tos;
+ call_stack = true;
}
for (i = 0; i < num; i++) {
@@ -555,6 +590,13 @@ static void intel_pmu_lbr_read_64(struct cpu_hw_events *cpuc)
from = rdlbr_from(lbr_idx);
to = rdlbr_to(lbr_idx);
+ /*
+ * Read LBR call stack entries
+ * until invalid entry (0s) is detected.
+ */
+ if (call_stack && !from)
+ break;
+
if (lbr_format == LBR_FORMAT_INFO && need_info) {
u64 info;