nachos3.4 threads管理 (c++)
Main.cc
//引导代码初始化操作系统内核。允许直接调用内部操作系统功能,简化调试和测试。在实践中,bootstrap代码只会初始化数据结构,
//并启动一个用户程序来打印登录提示。//许多内容只有在分配之后才是需要的。
(比如说在线程管理中,我们只定义了THREAD,这样文件系统等相关信息就不会被执行)
// Usage: nachos -d <debugflags> -rs <random seed #>
// -s -x <nachos file> -c <consoleIn> <consoleOut>
// -f -cp <unix file> <nachos file>
// -p <nachos file> -r <nachos file> -l -D -t
// -n <network reliability> -m <machine id>
// -o <other machine id>
// -z
//
// -d causes certain debugging messages to be printed (cf. utility.h)
// -rs causes Yield to occur at random (but repeatable) spots
// -z prints the copyright message
//
// USER_PROGRAM
// -s causes user programs to be executed in single-step mode
// -x runs a user program
// -c tests the con
-d 与调试信息相关,如果执行时增加参数 -d -t 则是打印出和thread相关的调试信息,如果执行时增加参数 -d + 则打印出所有调试信息。否则不打印。
-d 所跟的参数代表了需要打印哪些相关参数(具体见utility.h)
-rs 在指定的范围内随机触发线程的Yield方法,让出cpu,这个范围就是-rs 之后跟的参数(个人理解,不一定对)
-z 打印版本信息
之后都是与 USER_PROGRAM,FILESYS,NETWORK相关的内容,现在先不考虑
// FILESYS
// -f causes the physical disk to be formatted
// -cp copies a file from UNIX to Nachos
// -p prints a Nachos file to stdout
// -r removes a Nachos file from the file system
// -l lists the contents of the Nachos directory
// -D prints the contents of the entire file system
// -t tests the performance of the Nachos file system
//
// NETWORK
// -n sets the network reliability
// -m sets this machine's host id (needed for the network)
// -o runs a simple test of the Nachos network software
//
// NOTE -- flags are ignored until the relevant assignment.
// Some of the flags are interpreted here; some in system.cc.
//
// Copyright (c) 1992-1993 The Regents of the University of California.
// All rights reserved. See copyright.h for copyright notice and limitation
// of liability and disclaimer of warranty provisions.
#define MAIN #include "copyright.h" #undef MAIN #include "utility.h" #include "system.h" #ifdef THREADS extern int testnum; #endif // External functions used by this file extern void ThreadTest(void), Copy(char *unixFile, char *nachosFile); extern void Print(char *file), PerformanceTest(void); extern void StartProcess(char *file), ConsoleTest(char *in, char *out); extern void MailTest(int networkID);
#ifdef THREADS
extern int testnum;
#endif
由于现在分析的是线程管理过程,我们在Makefile中只定义了THREADS
DEFINES = -DTHREADS
所以将会定义参数testnum,用来记录测试的线程数。
在额外函数中,我们只调用了如下函数,该函数在threadtest.cc 文件中,执行一个线程测试。
extern void ThreadTest(void)
//---------------------------------------------------------------------- // main // Bootstrap the operating system kernel. // // Check command line arguments // Initialize data structures // (optionally) Call test procedure // // "argc" is the number of command line arguments (including the name of the command) -- ex: "nachos -d +" -> argc = 3 // "argv " is an array of strings, one for each command line argument ex: "nachos -d +" -> argv = {"nachos", "-d", "+"} //----------------------------------------------------------------------
int main(int argc, char **argv) { int argCount; // the number of arguments // for a particular command DEBUG('t', "Entering main"); (void) Initialize(argc, argv); #ifdef THREADS for (argc--, argv++; argc > 0; argc -= argCount, argv += argCount) { argCount = 1; switch (argv[0][1]) { case 'q': testnum = atoi(argv[1]); argCount++; break; default: testnum = 1; break; } } ThreadTest(); #endif