EX2 ten ticks

.gitignore

@@ -14,3 +14,4 @@ kernel
 kernelmemfs
 mkfs
 .gdbinit
+.idea

Makefile

@@ -51,7 +51,7 @@ TOOLPREFIX := $(shell if i386-jos-elf-objdump -i 2>&1 | grep '^elf32-i386$$' >/d
 endif
 
 # If the makefile can't find QEMU, specify its path here
-# QEMU = qemu-system-i386
+QEMU = qemu-system-i386
 
 # Try to infer the correct QEMU
 ifndef QEMU
@@ -76,7 +76,7 @@ AS = $(TOOLPREFIX)gas
 LD = $(TOOLPREFIX)ld
 OBJCOPY = $(TOOLPREFIX)objcopy
 OBJDUMP = $(TOOLPREFIX)objdump
-CFLAGS = -fno-pic -static -fno-builtin -fno-strict-aliasing -O2 -Wall -MD -ggdb -m32 -Werror -fno-omit-frame-pointer
+CFLAGS = -fno-pic -static -fno-builtin -fno-strict-aliasing -O2 -Wall -MD -ggdb -m32 -fno-omit-frame-pointer
 CFLAGS += $(shell $(CC) -fno-stack-protector -E -x c /dev/null >/dev/null 2>&1 && echo -fno-stack-protector)
 ASFLAGS = -m32 -gdwarf-2 -Wa,-divide
 # FreeBSD ld wants ``elf_i386_fbsd''
@@ -181,6 +181,8 @@ UPROGS=\
 	_usertests\
 	_wc\
 	_zombie\
+	_hello\
+	_ticktest\
 
 fs.img: mkfs README $(UPROGS)
 	./mkfs fs.img README $(UPROGS)
@@ -217,7 +219,7 @@ QEMUGDB = $(shell if $(QEMU) -help | grep -q '^-gdb'; \
 	then echo "-gdb tcp::$(GDBPORT)"; \
 	else echo "-s -p $(GDBPORT)"; fi)
 ifndef CPUS
-CPUS := 2
+CPUS := 1
 endif
 QEMUOPTS = -drive file=fs.img,index=1,media=disk,format=raw -drive file=xv6.img,index=0,media=disk,format=raw -smp $(CPUS) -m 512 $(QEMUEXTRA)
 

hello.c

@@ -0,0 +1,12 @@
+// Test syscall hello.
+
+#include "types.h"
+#include "stat.h"
+#include "user.h"
+
+int
+main(void)
+{
+  hello();
+  exit();
+}

proc.c

@@ -324,6 +324,7 @@ scheduler(void)
 {
   struct proc *p;
   struct cpu *c = mycpu();
+  int ticks_run;
   c->proc = 0;
 
   for(;;){
@@ -333,21 +334,29 @@ scheduler(void)
     // Loop over process table looking for process to run.
     acquire(&ptable.lock);
     for(p = ptable.proc; p < &ptable.proc[NPROC]; p++){
+      // Looking for RUNNABLE process
       if(p->state != RUNNABLE)
         continue;
 
-      // Switch to chosen process.  It is the process's job
-      // to release ptable.lock and then reacquire it
-      // before jumping back to us.
-      c->proc = p;
-      switchuvm(p);
-      p->state = RUNNING;
+      cprintf("Scheduler starts running process %d\n", p->pid);
 
-      swtch(&(c->scheduler), p->context);
-      switchkvm();
+      for (ticks_run = 1; ticks_run <= 10; ticks_run++) {
+        if (p->state == ZOMBIE)
+            break;
+
+        c->proc = p;
+        switchuvm(p);
+        p->state = RUNNING;
+
+        swtch(&(c->scheduler), p->context);
+        switchkvm();
+
+        cprintf("Process %d finished running %d ticks\n", p->pid, ticks_run);
+      }
 
       // Process is done running for now.
       // It should have changed its p->state before coming back.
+      cprintf("Finished running process %d\n", p->pid);
       c->proc = 0;
     }
     release(&ptable.lock);

syscall.c

@@ -103,6 +103,7 @@ extern int sys_unlink(void);
 extern int sys_wait(void);
 extern int sys_write(void);
 extern int sys_uptime(void);
+extern int sys_hello(void);
 
 static int (*syscalls[])(void) = {
 [SYS_fork]    sys_fork,
@@ -126,6 +127,7 @@ static int (*syscalls[])(void) = {
 [SYS_link]    sys_link,
 [SYS_mkdir]   sys_mkdir,
 [SYS_close]   sys_close,
+[SYS_hello]   sys_hello,
 };
 
 void

syscall.h

@@ -20,3 +20,4 @@
 #define SYS_link   19
 #define SYS_mkdir  20
 #define SYS_close  21
+#define SYS_hello  22

sysproc.c

@@ -89,3 +89,10 @@ sys_uptime(void)
   release(&tickslock);
   return xticks;
 }
+
+int
+sys_hello(void)
+{
+  cprintf("Hello from xv6!\n");
+  return 0;
+}

ticktest.c

@@ -0,0 +1,31 @@
+#include "types.h"
+#include "stat.h"
+#include "user.h"
+
+#define NUM_PROCESSES 5
+
+void busy_work() {
+  for (int i = 0; i <= 100000000; i++){
+    continue;
+  }
+  exit();
+}
+
+int main(void) {
+  int i;
+
+  for (i = 0; i < NUM_PROCESSES; i++) {
+    int pid = fork();
+    if (pid == 0) {
+      // Child process: sleep
+      busy_work();
+    }
+  }
+
+  // Parent process: wait for all children
+  for (i = 0; i < NUM_PROCESSES; i++) {
+    wait();
+  }
+
+  exit();
+}

user.h

@@ -23,6 +23,7 @@ int getpid(void);
 char* sbrk(int);
 int sleep(int);
 int uptime(void);
+int hello(void);
 
 // ulib.c
 int stat(const char*, struct stat*);

usys.S

@@ -29,3 +29,4 @@ SYSCALL(getpid)
 SYSCALL(sbrk)
 SYSCALL(sleep)
 SYSCALL(uptime)
+SYSCALL(hello)