@@ -29,6 +29,7 @@
#include <linux/kernel.h>
#include <linux/math.h>
#include <linux/mutex.h>
+#include <linux/percpu.h>
#include <linux/percpu-defs.h>
#include <linux/printk.h>
#include <linux/processor.h>
@@ -172,6 +173,35 @@ static struct workqueue_struct *hfi_updates_wq;
#define HFI_UPDATE_INTERVAL HZ
#define HFI_MAX_THERM_NOTIFY_COUNT 16
+#ifdef CONFIG_IPC_CLASSES
+static int __percpu *hfi_ipcc_scores;
+
+static int alloc_hfi_ipcc_scores(void)
+{
+ hfi_ipcc_scores = __alloc_percpu(sizeof(*hfi_ipcc_scores) *
+ hfi_features.nr_classes,
+ sizeof(*hfi_ipcc_scores));
+
+ return !hfi_ipcc_scores;
+}
+
+static void set_hfi_ipcc_score(void *caps, int cpu)
+{
+ int i, *hfi_class = per_cpu_ptr(hfi_ipcc_scores, cpu);
+
+ for (i = 0; i < hfi_features.nr_classes; i++) {
+ struct hfi_cpu_data *class_caps;
+
+ class_caps = caps + i * hfi_features.class_stride;
+ WRITE_ONCE(hfi_class[i], class_caps->perf_cap);
+ }
+}
+
+#else
+static int alloc_hfi_ipcc_scores(void) { return 0; }
+static void set_hfi_ipcc_score(void *caps, int cpu) { }
+#endif /* CONFIG_IPC_CLASSES */
+
static void get_hfi_caps(struct hfi_instance *hfi_instance,
struct thermal_genl_cpu_caps *cpu_caps)
{
@@ -194,6 +224,8 @@ static void get_hfi_caps(struct hfi_instance *hfi_instance,
cpu_caps[i].efficiency = caps->ee_cap << 2;
++i;
+
+ set_hfi_ipcc_score(caps, cpu);
}
raw_spin_unlock_irq(&hfi_instance->table_lock);
}
@@ -572,8 +604,14 @@ void __init intel_hfi_init(void)
if (!hfi_updates_wq)
goto err_nomem;
+ if (alloc_hfi_ipcc_scores())
+ goto err_ipcc;
+
return;
+err_ipcc:
+ destroy_workqueue(hfi_updates_wq);
+
err_nomem:
for (j = 0; j < i; ++j) {
hfi_instance = &hfi_instances[j];
The scheduler reads the IPCC scores when balancing load. These reads can be quite frequent. Hardware can also update the HFI table frequently. Concurrent access may cause a lot of contention. It gets worse as the number of CPUs increases. Instead, create separate per-CPU IPCC scores that the scheduler can read without the HFI table lock. Cc: Ben Segall <bsegall@google.com> Cc: Daniel Bristot de Oliveira <bristot@redhat.com> Cc: Dietmar Eggemann <dietmar.eggemann@arm.com> Cc: Joel Fernandes (Google) <joel@joelfernandes.org> Cc: Len Brown <len.brown@intel.com> Cc: Mel Gorman <mgorman@suse.de> Cc: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Cc: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Tim C. Chen <tim.c.chen@intel.com> Cc: Valentin Schneider <vschneid@redhat.com> Cc: x86@kernel.org Cc: linux-pm@vger.kernel.org Cc: linux-kernel@vger.kernel.org Suggested-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Ricardo Neri <ricardo.neri-calderon@linux.intel.com> --- Changes since v1: * Added this patch. --- drivers/thermal/intel/intel_hfi.c | 38 +++++++++++++++++++++++++++++++ 1 file changed, 38 insertions(+)