学编程做网站,佛山北京网站建设公司,linux主网站设计,长尾关键词挖掘工具爱网站在linux下用 top -H -p pid 查询某个进程的线程 按理说#xff0c;都是某个进程下的线程#xff0c; 应该进程id PID一样啊#xff0c;但实际却都不一样
实际是被PID的名字给弄混了#xff0c;线程进程都会有自己的ID#xff0c;这个ID就叫做PID#xff0c;P…在linux下用 top -H -p pid 查询某个进程的线程 按理说都是某个进程下的线程 应该进程id PID一样啊但实际却都不一样
实际是被PID的名字给弄混了线程进程都会有自己的ID这个ID就叫做PIDPID是不特指进程ID线程ID也可以叫做PID。
pthread库里的每一个线程都对应一个内核线程都是有单独的pid。 The four threads will have the same PID but only when viewed from above. What you (as a user) call a PID is not what the kernel (looking from below) calls a PID. In the kernel, each thread has its own ID, called a PID (although it would possibly make more sense to call this a TID, or thread ID) and they also have a TGID (thread group ID) which is the PID of the thread that started the whole process. Simplistically, when a new process is created, it appears as a thread where both the PID and TGID are the same (new) number. When a thread starts another thread, that started thread gets its own PID (so the scheduler can schedule it independently) but it inherits the TGID from the original thread. That way, the kernel can happily schedule threads independent of what process they belong to, while processes (thread group IDs) are reported to you. 关于线程继承关系图如下 USER VIEW-- PID 43 -- ----------------- PID 42 --------------------------| process |_| pid42 |__/ | tgid42 | \_ (new thread) __ (fork) _/ --------- \/ ---------
--------- | process |
| process | | pid44 |
| pid43 | | tgid42 |
| tgid43 | ---------
----------- PID 43 -- --------- PID 42 -------- --- PID 44 ---KERNEL VIEW 在这里你可以清晰的看到创建一个新的进程会给一个新的PID和TGID并且2个值相同当创建一个新的线程的时候会给你一个新的PID并且TGID和之前开始的进程一致。 Linux通过进程查看线程的方法 1).htop按t(显示进程线程嵌套关系)和H(显示线程) 然后F4过滤进程名。2).ps -eLf | grep java(快照带线程命令e是显示全部进程L是显示线程f全格式输出) 3).pstree -p pid(显示进程树不加pid显示所有) 4).top -Hp pid (实时) 5).ps -T -p pid(快照) 推荐程度按数字从小到大。 打印线程的PID的方法如下 getpid()方法可以打印进程的PID gettid()方法可以打印线程的PID void * thread_start(void *arg) { printf(Process ID: %d, thread ID %d\n, getpid(), gettid()); } 由于gettid()在glibc中没有包含Note: There is no glibc wrapper for this system call; see NOTES. 所以用如下syscall函数在用户空间替代gettid()的功能syscall(__NR_gettid)) 或者 syscall(SYS_gettid) 在文件 /usr/include/bits/syscall.h里 有一行 #define SYS_gettid __NR_gettid 可见二者是一样的。__NR_gettid是系统调用号#include pthread.h #include stdio.h #include sys/types.h #include sys/syscall.h #include unistd.h void * thread_start(void *arg) { printf([1] Process ID: %d, thread ID %d\n, getpid(), syscall(__NR_gettid)); printf([2] Process ID: %d, thread ID %d\n, getpid(), syscall(SYS_gettid)); }
