From 90203803d3d8ddf7d2c9a3a0a74d898b8a4c6672 Mon Sep 17 00:00:00 2001
From: fslongjin <fslongjin@vip.qq.com>
Date: Wed, 27 Jul 2022 21:19:59 +0800
Subject: [PATCH] =?UTF-8?q?:new:=20=E4=BD=BF=E7=94=A8rdtsc=E8=BF=9B?=
 =?UTF-8?q?=E8=A1=8C=E7=B2=BE=E7=A1=AE=E5=AE=9A=E6=97=B6?=
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---
 kernel/process/process.c |  1 +
 kernel/time/sleep.c      | 29 +++++++++++++++++++----------
 2 files changed, 20 insertions(+), 10 deletions(-)

diff --git a/kernel/process/process.c b/kernel/process/process.c
index 205565b4..36bcadd9 100644
--- a/kernel/process/process.c
+++ b/kernel/process/process.c
@@ -5,6 +5,7 @@
 #include <common/stdio.h>
 #include <common/compiler.h>
 #include <common/libELF/elf.h>
+#include <common/time.h>
 #include <driver/video/video.h>
 #include <driver/usb/usb.h>
 #include <exception/gate.h>
diff --git a/kernel/time/sleep.c b/kernel/time/sleep.c
index 6646c205..05be1685 100644
--- a/kernel/time/sleep.c
+++ b/kernel/time/sleep.c
@@ -4,6 +4,9 @@
 #include <process/process.h>
 #include <sched/sched.h>
 #include <mm/slab.h>
+#include <common/cpu.h>
+#include <common/glib.h>
+
 /**
  * @brief nanosleep定时事件到期后，唤醒指定的进程
  *
@@ -24,26 +27,32 @@ void nanosleep_handler(void *pcb)
 int nanosleep(const struct timespec *rqtp, struct timespec *rmtp)
 {
     int64_t total_ns = rqtp->tv_nsec;
-    // kdebug("totalns = %ld", total_ns);
+
     if (total_ns < 0 || total_ns >= 1000000000)
         return -EINVAL;
 
-    // todo: 对于小于500us的时间，使用spin/rdtsc来进行定时
-    if (total_ns < 50000)
-        return 0;
-
+    // 对于小于500us的时间，使用spin/rdtsc来进行定时
     if (total_ns < 500000)
-        total_ns = 500000;
+    {
+        kdebug("use rdtsc to nanosleep");
+        uint64_t expired_tsc = rdtsc() + (total_ns * Cpu_tsc_freq) / 1000000000;
+        while (rdtsc() < expired_tsc)
+            pause();
+
+        if (rmtp != NULL)
+        {
+            rmtp->tv_nsec = 0;
+            rmtp->tv_sec = 0;
+        }
+        return 0;
+    }
 
     // 增加定时任务
     struct timer_func_list_t *sleep_task = (struct timer_func_list_t *)kmalloc(sizeof(struct timer_func_list_t), 0);
     memset(sleep_task, 0, sizeof(struct timer_func_list_t));
 
-    
-
-    
     timer_func_init_us(sleep_task, &nanosleep_handler, (void *)current_pcb, total_ns / 1000);
-    
+
     timer_func_add(sleep_task);
 
     current_pcb->state = PROC_INTERRUPTIBLE;