@@ -187,6 +187,19 @@ static struct workqueue_struct *hfi_updates_wq;
#ifdef CONFIG_IPC_CLASSES
static int __percpu *hfi_ipcc_scores;
+/*
+ * A task may be unclassified if it has been recently created, spend most of
+ * its lifetime sleeping, or hardware has not provided a classification.
+ *
+ * Most tasks will be classified as scheduler's IPC class 1 (HFI class 0)
+ * eventually. Meanwhile, the scheduler will place tasks of higher IPC score
+ * on higher-performance CPUs.
+ *
+ * IPC class 1 is a reasonable choice. It matches the performance capability
+ * of the legacy, classless, HFI table.
+ */
+#define HFI_UNCLASSIFIED_DEFAULT 1
+
int intel_hfi_has_ipc_classes(void)
{
return cpu_feature_enabled(X86_FEATURE_ITD);
@@ -222,7 +235,7 @@ int intel_hfi_get_ipcc_score(unsigned short ipcc, int cpu)
return -EINVAL;
if (ipcc == IPC_CLASS_UNCLASSIFIED)
- return -EINVAL;
+ ipcc = HFI_UNCLASSIFIED_DEFAULT;
/*
* Scheduler IPC classes start at 1. HFI classes start at 0.
A task may be unclassified if it has been recently created, spend most of its lifetime sleeping, or hardware has not provided a classification. Most tasks will be eventually classified as scheduler's IPC class 1 (HFI class 0). This class corresponds to the capabilities in the legacy, classless, HFI table. IPC class 1 is a reasonable choice until hardware provides an actual classification. Meanwhile, the scheduler will place other tasks with higher scores on higher-performance CPUs. Cc: Ben Segall <bsegall@google.com> Cc: Daniel Bristot de Oliveira <bristot@redhat.com> Cc: Dietmar Eggemann <dietmar.eggemann@arm.com> 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 Signed-off-by: Ricardo Neri <ricardo.neri-calderon@linux.intel.com> --- Changes since v1: * Now the default class is 1. --- drivers/thermal/intel/intel_hfi.c | 15 ++++++++++++++- 1 file changed, 14 insertions(+), 1 deletion(-)