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HV: Use the mwait instead of pause for cpu_idle

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Now it will use the pause when cpu is in idle state. It will consume
more power. If the mwait is supported, it will use the monitor/mwait to
enter the deep CPU C-state. It helps to save power.

Signed-off-by: Zhao Yakui <yakui.zhao@intel.com>
This commit is contained in:
Zhao Yakui 2019-08-27 16:25:39 +08:00
parent 21bd1c8bd3
commit a7706e0c39
4 changed files with 49 additions and 17 deletions
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39
hypervisor/arch/x86/cpu.c
View File

@ -367,9 +367,34 @@ void stop_pcpus(void)
wait_pcpus_offline(mask);
}
static
inline void asm_monitor(const uint64_t *addr, uint64_t ecx, uint64_t edx)
{
asm volatile("monitor\n" : : "a" (addr), "c" (ecx), "d" (edx));
}
static
inline void asm_mwait(uint64_t eax, uint64_t ecx)
{
asm volatile("mwait\n" : : "a" (eax), "c" (ecx));
}
void cpu_do_idle(void)
{
asm_pause();
uint16_t pcpu_id = get_pcpu_id();
struct sched_context *ctx = &per_cpu(sched_ctx, pcpu_id);
if (ctx->mwait_flags) {
CPU_IRQ_DISABLE();
asm_monitor(&ctx->flags, 0UL, 0UL);
if (!bitmap_test(NEED_RESCHEDULE, &ctx->flags))
asm_mwait(0x60UL, 1UL);
CPU_IRQ_ENABLE();
} else {
CPU_IRQ_ENABLE();
asm_pause();
CPU_IRQ_DISABLE();
}
}
/**
@ -415,18 +440,6 @@ static void print_hv_banner(void)
printf(boot_msg);
}
static
inline void asm_monitor(const uint64_t *addr, uint64_t ecx, uint64_t edx)
{
asm volatile("monitor\n" : : "a" (addr), "c" (ecx), "d" (edx));
}
static
inline void asm_mwait(uint64_t eax, uint64_t ecx)
{
asm volatile("mwait\n" : : "a" (eax), "c" (ecx));
}
/* wait until *sync == wake_sync */
void wait_sync_change(uint64_t *sync, uint64_t wake_sync)
{

2
hypervisor/common/hv_main.c
View File

@ -92,9 +92,7 @@ void default_idle(__unused struct sched_object *obj)
} else if (need_shutdown_vm(pcpu_id)) {
shutdown_vm_from_idle(pcpu_id);
} else {
CPU_IRQ_ENABLE();
cpu_do_idle();
CPU_IRQ_DISABLE();
}
}
}

19
hypervisor/common/schedule.c
View File

@ -12,6 +12,12 @@
#include <lapic.h>
#include <schedule.h>
#include <sprintf.h>
#include <cpuid.h>
#include <cpu_caps.h>
#define CPUID_MWAIT_LEAF 5
#define CPUID5_ECX_EXTENSIONS_SUPPORTED 0x1
#define CPUID5_ECX_INTERRUPT_BREAK 0x2
static uint64_t pcpu_used_bitmap;
@ -20,7 +26,19 @@ void init_scheduler(void)
struct sched_context *ctx;
uint32_t i;
uint16_t pcpu_nums = get_pcpu_nums();
uint32_t mwait_flag = 0;
if (has_monitor_cap()) {
uint32_t eax, ebx, ecx, edx;
mwait_flag = 1;
cpuid(CPUID_MWAIT_LEAF, &eax, &ebx, &ecx, &edx);
if (!(ecx & CPUID5_ECX_EXTENSIONS_SUPPORTED) ||
!(ecx & CPUID5_ECX_INTERRUPT_BREAK) ||
!edx) {
mwait_flag = 0;
}
}
for (i = 0U; i < pcpu_nums; i++) {
ctx = &per_cpu(sched_ctx, i);
@ -29,6 +47,7 @@ void init_scheduler(void)
INIT_LIST_HEAD(&ctx->runqueue);
ctx->flags = 0UL;
ctx->curr_obj = NULL;
ctx->mwait_flags = mwait_flag;
}
}

6
hypervisor/include/common/schedule.h
View File

@ -28,12 +28,14 @@ struct sched_object {
};
struct sched_context {
uint64_t flags;
uint64_t mwait_flags;
uint64_t rserved[6];
spinlock_t runqueue_lock;
struct list_head runqueue;
uint64_t flags;
struct sched_object *curr_obj;
spinlock_t scheduler_lock;
};
} __aligned(64);
void init_scheduler(void);
void switch_to_idle(run_thread_t idle_thread);