[PATCH] LoongArch: Add SMT (Simultaneous Multi-Threading) support
From: Liupu Wang
Date: Wed Jun 14 2023 - 05:38:14 EST
From: Huacai Chen <chenhuacai@xxxxxxxxxxx>
Loongson-3A6000 has SMT (Simultaneous Multi-Threading) support, each
physical core has two logical cores (threads). This patch add SMT probe
and scheduler support via ACPI PPTT.
If SCHED_SMT enabled, Loongson-3A6000 is treated as 4 cores, 8 threads;
If SCHED_SMT disabled, Loongson-3A6000 is treated as 8 cores, 8 threads.
Remove smp_num_siblings to support HMP (Heterogeneous Multi-Processing).
Signed-off-by: Liupu Wang <wangliupu@xxxxxxxxxxx>
Signed-off-by: Huacai Chen <chenhuacai@xxxxxxxxxxx>
---
arch/loongarch/Kconfig | 8 +++++++
arch/loongarch/include/asm/acpi.h | 9 ++++++++
arch/loongarch/include/asm/cpu-info.h | 1 +
arch/loongarch/kernel/acpi.c | 32 +++++++++++++++++++++++++++
arch/loongarch/kernel/proc.c | 1 +
arch/loongarch/kernel/smp.c | 24 +++++++++-----------
drivers/acpi/Kconfig | 2 +-
7 files changed, 62 insertions(+), 15 deletions(-)
diff --git a/arch/loongarch/Kconfig b/arch/loongarch/Kconfig
index d38b066fc931..6d36b681068e 100644
--- a/arch/loongarch/Kconfig
+++ b/arch/loongarch/Kconfig
@@ -5,6 +5,7 @@ config LOONGARCH
select ACPI
select ACPI_GENERIC_GSI if ACPI
select ACPI_MCFG if ACPI
+ select ACPI_PPTT if ACPI
select ACPI_SYSTEM_POWER_STATES_SUPPORT if ACPI
select ARCH_BINFMT_ELF_STATE
select ARCH_ENABLE_MEMORY_HOTPLUG
@@ -372,6 +373,13 @@ config EFI_STUB
This kernel feature allows the kernel to be loaded directly by
EFI firmware without the use of a bootloader.
+config SCHED_SMT
+ bool "SMT scheduler support"
+ default y
+ help
+ Improves scheduler's performance when there are multiple
+ threads in one physical core.
+
config SMP
bool "Multi-Processing support"
help
diff --git a/arch/loongarch/include/asm/acpi.h b/arch/loongarch/include/asm/acpi.h
index 976a810352c6..5c78b5d2bfb7 100644
--- a/arch/loongarch/include/asm/acpi.h
+++ b/arch/loongarch/include/asm/acpi.h
@@ -13,6 +13,7 @@ extern int acpi_strict;
extern int acpi_disabled;
extern int acpi_pci_disabled;
extern int acpi_noirq;
+extern int pptt_enabled;
#define acpi_os_ioremap acpi_os_ioremap
void __iomem *acpi_os_ioremap(acpi_physical_address phys, acpi_size size);
@@ -30,6 +31,14 @@ static inline bool acpi_has_cpu_in_madt(void)
}
extern struct list_head acpi_wakeup_device_list;
+extern struct acpi_madt_core_pic acpi_core_pic[NR_CPUS];
+
+extern int __init parse_acpi_topology(void);
+
+static inline u32 get_acpi_id_for_cpu(unsigned int cpu)
+{
+ return acpi_core_pic[cpu_logical_map(cpu)].processor_id;
+}
#endif /* !CONFIG_ACPI */
diff --git a/arch/loongarch/include/asm/cpu-info.h b/arch/loongarch/include/asm/cpu-info.h
index cd73a6f57fe3..900589cb159d 100644
--- a/arch/loongarch/include/asm/cpu-info.h
+++ b/arch/loongarch/include/asm/cpu-info.h
@@ -54,6 +54,7 @@ struct cpuinfo_loongarch {
struct cache_desc cache_leaves[CACHE_LEAVES_MAX];
int core; /* physical core number in package */
int package;/* physical package number */
+ int global_id; /* physical global thread number */
int vabits; /* Virtual Address size in bits */
int pabits; /* Physical Address size in bits */
unsigned int ksave_mask; /* Usable KSave mask. */
diff --git a/arch/loongarch/kernel/acpi.c b/arch/loongarch/kernel/acpi.c
index 98f431157e4c..9450e09073eb 100644
--- a/arch/loongarch/kernel/acpi.c
+++ b/arch/loongarch/kernel/acpi.c
@@ -33,6 +33,8 @@ u64 acpi_saved_sp;
#define PREFIX "ACPI: "
+struct acpi_madt_core_pic acpi_core_pic[NR_CPUS];
+
void __init __iomem * __acpi_map_table(unsigned long phys, unsigned long size)
{
@@ -99,6 +101,7 @@ acpi_parse_processor(union acpi_subtable_headers *header, const unsigned long en
acpi_table_print_madt_entry(&header->common);
#ifdef CONFIG_SMP
+ acpi_core_pic[processor->core_id] = *processor;
set_processor_mask(processor->core_id, processor->flags);
#endif
@@ -140,6 +143,35 @@ static void __init acpi_process_madt(void)
loongson_sysconf.nr_cpus = num_processors;
}
+int pptt_enabled;
+
+int __init parse_acpi_topology(void)
+{
+ int cpu, topology_id;
+
+ for_each_possible_cpu(cpu) {
+ topology_id = find_acpi_cpu_topology(cpu, 0);
+ if (topology_id < 0) {
+ pr_warn("Invalid BIOS PPTT\n");
+ return -ENOENT;
+ }
+
+ if (acpi_pptt_cpu_is_thread(cpu) <= 0)
+ cpu_data[cpu].core = topology_id;
+ else {
+ topology_id = find_acpi_cpu_topology(cpu, 1);
+ if (topology_id < 0)
+ return -ENOENT;
+
+ cpu_data[cpu].core = topology_id;
+ }
+ }
+
+ pptt_enabled = 1;
+
+ return 0;
+}
+
#ifndef CONFIG_SUSPEND
int (*acpi_suspend_lowlevel)(void);
#else
diff --git a/arch/loongarch/kernel/proc.c b/arch/loongarch/kernel/proc.c
index 0d82907b5404..d4b270630bb5 100644
--- a/arch/loongarch/kernel/proc.c
+++ b/arch/loongarch/kernel/proc.c
@@ -49,6 +49,7 @@ static int show_cpuinfo(struct seq_file *m, void *v)
seq_printf(m, "processor\t\t: %ld\n", n);
seq_printf(m, "package\t\t\t: %d\n", cpu_data[n].package);
seq_printf(m, "core\t\t\t: %d\n", cpu_data[n].core);
+ seq_printf(m, "global_id\t\t: %d\n", cpu_data[n].global_id);
seq_printf(m, "CPU Family\t\t: %s\n", __cpu_family[n]);
seq_printf(m, "Model Name\t\t: %s\n", __cpu_full_name[n]);
seq_printf(m, "CPU Revision\t\t: 0x%02x\n", version);
diff --git a/arch/loongarch/kernel/smp.c b/arch/loongarch/kernel/smp.c
index ed167e244cda..062f3fe8df60 100644
--- a/arch/loongarch/kernel/smp.c
+++ b/arch/loongarch/kernel/smp.c
@@ -8,6 +8,7 @@
* Copyright (C) 2000, 2001 Silicon Graphics, Inc.
* Copyright (C) 2000, 2001, 2003 Broadcom Corporation
*/
+#include <linux/acpi.h>
#include <linux/cpu.h>
#include <linux/cpumask.h>
#include <linux/init.h>
@@ -37,10 +38,6 @@ EXPORT_SYMBOL(__cpu_number_map);
int __cpu_logical_map[NR_CPUS]; /* Map logical to physical */
EXPORT_SYMBOL(__cpu_logical_map);
-/* Number of threads (siblings) per CPU core */
-int smp_num_siblings = 1;
-EXPORT_SYMBOL(smp_num_siblings);
-
/* Representing the threads (siblings) of each logical CPU */
cpumask_t cpu_sibling_map[NR_CPUS] __read_mostly;
EXPORT_SYMBOL(cpu_sibling_map);
@@ -228,9 +225,12 @@ void __init loongson_prepare_cpus(unsigned int max_cpus)
{
int i = 0;
+ parse_acpi_topology();
+
for (i = 0; i < loongson_sysconf.nr_cpus; i++) {
set_cpu_present(i, true);
csr_mail_send(0, __cpu_logical_map[i], 0);
+ cpu_data[i].global_id = __cpu_logical_map[i];
}
per_cpu(cpu_state, smp_processor_id()) = CPU_ONLINE;
@@ -271,10 +271,10 @@ void loongson_init_secondary(void)
numa_add_cpu(cpu);
#endif
per_cpu(cpu_state, cpu) = CPU_ONLINE;
- cpu_data[cpu].core =
- cpu_logical_map(cpu) % loongson_sysconf.cores_per_package;
cpu_data[cpu].package =
cpu_logical_map(cpu) / loongson_sysconf.cores_per_package;
+ cpu_data[cpu].core = pptt_enabled ? cpu_data[cpu].core :
+ cpu_logical_map(cpu) % loongson_sysconf.cores_per_package;
}
void loongson_smp_finish(void)
@@ -380,14 +380,10 @@ static inline void set_cpu_sibling_map(int cpu)
cpumask_set_cpu(cpu, &cpu_sibling_setup_map);
- if (smp_num_siblings <= 1)
- cpumask_set_cpu(cpu, &cpu_sibling_map[cpu]);
- else {
- for_each_cpu(i, &cpu_sibling_setup_map) {
- if (cpus_are_siblings(cpu, i)) {
- cpumask_set_cpu(i, &cpu_sibling_map[cpu]);
- cpumask_set_cpu(cpu, &cpu_sibling_map[i]);
- }
+ for_each_cpu(i, &cpu_sibling_setup_map) {
+ if (cpus_are_siblings(cpu, i)) {
+ cpumask_set_cpu(i, &cpu_sibling_map[cpu]);
+ cpumask_set_cpu(cpu, &cpu_sibling_map[i]);
}
}
}
diff --git a/drivers/acpi/Kconfig b/drivers/acpi/Kconfig
index ccbeab9500ec..00dd309b6682 100644
--- a/drivers/acpi/Kconfig
+++ b/drivers/acpi/Kconfig
@@ -542,10 +542,10 @@ config ACPI_PFRUT
if ARM64
source "drivers/acpi/arm64/Kconfig"
+endif
config ACPI_PPTT
bool
-endif
config ACPI_PCC
bool "ACPI PCC Address Space"
--
2.39.1