prctl函数设置线程别名

prctl函数用法

NAME
       prctl - operations on a process

SYNOPSIS
       #include 

       int prctl(int option, unsigned long arg2, unsigned long arg3,
                 unsigned long arg4, unsigned long arg5);

DESCRIPTION
       prctl()  is  called with a first argument describing what to do (with values defined in <linux/prctl.h>), and further arguments with a significance
       depending on the first one.  The first argument can be:


PR_SET_NAME (since Linux 2.6.9)
              Set the name of the calling thread, using the value in the location pointed to by (char *) arg2.  The name can be up to 16 bytes  long,  and should  be  null-terminated  if it contains fewer bytes.  This is the same attribute that can be set via pthread_setname_np(3) and retrieved using pthread_getname_np(3).  The attribute is likewise accessible via /proc/self/task/[tid]/comm, where tid is  the  name  of  the  calling thread.

PR_GET_NAME (since Linux 2.6.11)
              Return  the  name  of  the calling thread, in the buffer pointed to by (char *) arg2.  The buffer should allow space for up to 16 bytes; the returned string will be null-terminated if it is shorter than that.

示例代码

#include 
#include 
#include 
#include 
#include   // PR_SET_NAME

inline void SetThreadName(const std::string& name)
{
    ::prctl(PR_SET_NAME, name.c_str());
}

volatile bool g_is_running = false;

int main()
{
    std::vector<std::thread*> thread_manager;
    thread_manager.reserve(20);

    g_is_running = true;

    for (int i = 0; i < 10; i++)
    {
        thread_manager.emplace_back(new std::thread([&](){
            SetThreadName("t-" + std::to_string(i));
            while (g_is_running)
            {
                usleep(1);
            }
        }));   
    }
    
    for (auto& thr : thread_manager)
    {
        thr->join();
    }

    return 0;
}

查看cpu使用情况

➜  ~ top -H -p 10287
top - 23:35:22 up 235 days, 12:17,  2 users,  load average: 0.22, 0.11, 0.07
Threads:  11 total,   2 running,   9 sleeping,   0 stopped,   0 zombie
%Cpu(s):  4.3 us, 10.5 sy,  0.0 ni, 85.2 id,  0.0 wa,  0.0 hi,  0.0 si,  0.0 st
KiB Mem :  8008616 total,   175312 free,   625272 used,  7208032 buff/cache
KiB Swap:        0 total,        0 free,        0 used.  7068056 avail Mem

  PID USER      PR  NI    VIRT    RES    SHR S %CPU %MEM     TIME+ COMMAND
10293 root      20   0   97904   1416   1212 S 17.6  0.0   0:10.94 t-6
10289 root      20   0   97904   1416   1212 S 17.3  0.0   0:10.95 t-2
10290 root      20   0   97904   1416   1212 S 17.3  0.0   0:10.91 t-4
10291 root      20   0   97904   1416   1212 S 17.3  0.0   0:10.93 t-4
10292 root      20   0   97904   1416   1212 R 17.3  0.0   0:10.94 t-5
10294 root      20   0   97904   1416   1212 S 17.3  0.0   0:10.92 t-7
10295 root      20   0   97904   1416   1212 R 17.3  0.0   0:10.92 t-8
10296 root      20   0   97904   1416   1212 S 17.3  0.0   0:10.92 t-9
10297 root      20   0   97904   1416   1212 S 17.3  0.0   0:10.89 t-10
10288 root      20   0   97904   1416   1212 S 16.9  0.0   0:10.92 t-1
10287 root      20   0   97904   1416   1212 S  0.0  0.0   0:00.00 app