[RFC PATCH 17/23] thermal: intel: hfi: Enable the Intel Thread Director

Ricardo Neri
2022-09-09T23:07:54Z

Enable Intel Thread Director from the CPU hotplug callback: globally from
CPU0 and then enable the thread-classification hardware in each logical
processor individually.

Also, initialize the number of classes supported.

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-kernel@vger.kernel.org
Signed-off-by: Ricardo Neri <ricardo.neri-calderon@linux.intel.com>
---
arch/x86/include/asm/msr-index.h | 2 ++
drivers/thermal/intel/Kconfig | 12 ++++++++++++
drivers/thermal/intel/intel_hfi.c | 30 ++++++++++++++++++++++++++++--
3 files changed, 42 insertions(+), 2 deletions(-)

diff --git a/arch/x86/include/asm/msr-index.h b/arch/x86/include/asm/msr-index.h
index 6674bdb096f3..810b950dc2e0 100644
--- a/arch/x86/include/asm/msr-index.h
+++ b/arch/x86/include/asm/msr-index.h
@@ -1053,5 +1053,7 @@
/* Hardware Feedback Interface */
#define MSR_IA32_HW_FEEDBACK_PTR 0x17d0
#define MSR_IA32_HW_FEEDBACK_CONFIG 0x17d1
+#define MSR_IA32_HW_FEEDBACK_THREAD_CONFIG 0x17d4
+#define MSR_IA32_HW_FEEDBACK_CHAR 0x17d2

#endif /* _ASM_X86_MSR_INDEX_H */
diff --git a/drivers/thermal/intel/Kconfig b/drivers/thermal/intel/Kconfig
index f0c845679250..8848bf45ffbc 100644
--- a/drivers/thermal/intel/Kconfig
+++ b/drivers/thermal/intel/Kconfig
@@ -113,3 +113,15 @@ config INTEL_HFI_THERMAL
These capabilities may change as a result of changes in the operating
conditions of the system such power and thermal limits. If selected,
the kernel relays updates in CPUs' capabilities to userspace.
+
+config INTEL_THREAD_DIRECTOR
+ bool "Intel Thread Director"
+ depends on INTEL_HFI_THERMAL
+ depends on SMP
+ select SCHED_TASK_CLASSES
+ help
+ Select this option to enable the Intel Thread Director. If selected,
+ hardware classifies tasks based on the type of instructions they
+ execute. It also provides performance capabilities for each class of
+ task. On hybrid processors, the scheduler uses this data to place
+ tasks of classes of higher performance on higher-performnance CPUs.
diff --git a/drivers/thermal/intel/intel_hfi.c b/drivers/thermal/intel/intel_hfi.c
index 967899d2c01f..9ddd3047eb39 100644
--- a/drivers/thermal/intel/intel_hfi.c
+++ b/drivers/thermal/intel/intel_hfi.c
@@ -49,6 +49,8 @@
/* Hardware Feedback Interface MSR configuration bits */
#define HW_FEEDBACK_PTR_VALID_BIT BIT(0)
#define HW_FEEDBACK_CONFIG_HFI_ENABLE_BIT BIT(0)
+#define HW_FEEDBACK_CONFIG_ITD_ENABLE_BIT BIT(1)
+#define HW_FEEDBACK_THREAD_CONFIG_ENABLE_BIT BIT(0)

/* CPUID detection and enumeration definitions for HFI */

@@ -73,6 +75,15 @@ union cpuid6_edx {
u32 full;
};

+union cpuid6_ecx {
+ struct {
+ u32 dont_care0:8;
+ u32 nr_classes:8;
+ u32 dont_care1:16;
+ } split;
+ u32 full;
+};
+
#ifdef CONFIG_INTEL_THREAD_DIRECTOR
union hfi_thread_feedback_char_msr {
struct {
@@ -481,6 +492,11 @@ void intel_hfi_online(unsigned int cpu)

init_hfi_cpu_index(info);

+ if (cpu_feature_enabled(X86_FEATURE_ITD)) {
+ msr_val = HW_FEEDBACK_THREAD_CONFIG_ENABLE_BIT;
+ wrmsrl(MSR_IA32_HW_FEEDBACK_THREAD_CONFIG, msr_val);
+ }
+
/*
* Now check if the HFI instance of the package/die of @cpu has been
* initialized (by checking its header). In such case, all we have to
@@ -536,6 +552,10 @@ void intel_hfi_online(unsigned int cpu)
*/
rdmsrl(MSR_IA32_HW_FEEDBACK_CONFIG, msr_val);
msr_val |= HW_FEEDBACK_CONFIG_HFI_ENABLE_BIT;
+
+ if (cpu_feature_enabled(X86_FEATURE_ITD))
+ msr_val |= HW_FEEDBACK_CONFIG_ITD_ENABLE_BIT;
+
wrmsrl(MSR_IA32_HW_FEEDBACK_CONFIG, msr_val);

unlock:
@@ -615,8 +635,14 @@ static __init int hfi_parse_features(void)
*/
hfi_features.class_stride = nr_capabilities;

- /* For now, use only one class of the HFI table */
- hfi_features.nr_classes = 1;
+ if (cpu_feature_enabled(X86_FEATURE_ITD)) {
+ union cpuid6_ecx ecx;
+
+ ecx.full = cpuid_ecx(CPUID_HFI_LEAF);
+ hfi_features.nr_classes = ecx.split.nr_classes;
+ } else {
+ hfi_features.nr_classes = 1;
+ }

/*
* The header contains change indications for each supported feature.
--
2.25.1