From a6c4f29f835a9c768f217cb1fbf70d385dce3569 Mon Sep 17 00:00:00 2001
From: Recolic Keghart <root@recolic.net>
Date: Sun, 29 Dec 2019 23:28:13 +0800
Subject: [PATCH] async device update
---
nemu/Makefile | 2 +-
nemu/src/device/device.cc | 26 +++++++++++++++++++-------
2 files changed, 20 insertions(+), 8 deletions(-)
diff --git a/nemu/Makefile b/nemu/Makefile
index 57860b6..d47a0af 100644
--- a/nemu/Makefile
+++ b/nemu/Makefile
@@ -53,7 +53,7 @@ NEMU_EXEC := $(BINARY) $(ARGS)
$(BINARY): $(OBJS)
$(call git_commit, "compile")
@echo + LD $@
- @$(LD) -O2 -rdynamic $(SO_LDLAGS) -o $@ $^ -lSDL2 -lreadline -ldl
+ @$(LD) -O2 -rdynamic $(SO_LDLAGS) -o $@ $^ -lSDL2 -lreadline -ldl -pthread
run: $(BINARY)
$(call git_commit, "run")
diff --git a/nemu/src/device/device.cc b/nemu/src/device/device.cc
index 560d1b0..b36ae40 100644
--- a/nemu/src/device/device.cc
+++ b/nemu/src/device/device.cc
@@ -6,13 +6,16 @@
#include <signal.h>
#include <SDL2/SDL.h>
+#include <thread>
+#include <atomic>
+
#define TIMER_HZ 100
#define VGA_HZ 50
static uint64_t jiffy = 0;
static struct itimerval it;
-static int device_update_flag = false;
-static int update_screen_flag = false;
+static std::atomic<bool> device_update_flag(false);
+static std::atomic<bool> update_screen_flag(false);
void init_serial();
void init_timer();
@@ -37,12 +40,9 @@ static void timer_sig_handler(int signum) {
Assert(ret == 0, "Can not set timer");
}
-void device_update() {
- if (!device_update_flag) {
- return;
- }
- device_update_flag = false;
+void device_update() {} // Now an independent thread will do it.
+void device_update_impl() {
if (update_screen_flag) {
update_screen();
update_screen_flag = false;
@@ -72,6 +72,16 @@ void device_update() {
}
}
+static void device_update_thread_daemon() {
+ while(true) {
+ if(device_update_flag.exchange(false)) {
+ device_update_impl();
+ }
+ // At most, 1000FPS
+ std::this_thread::sleep_for(std::chrono::milliseconds(1));
+ }
+}
+
void sdl_clear_event_queue() {
SDL_Event event;
while (SDL_PollEvent(&event));
@@ -93,6 +103,8 @@ void init_device() {
it.it_value.tv_usec = 1000000 / TIMER_HZ;
ret = setitimer(ITIMER_VIRTUAL, &it, NULL);
Assert(ret == 0, "Can not set timer");
+
+ std::thread(device_update_thread_daemon).detach();
}
#else
--
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