Comcat：/* Reference */

2025-12-04T06:37:23Z

‎Reference

Comcat：/* GLibc API */

2017-10-30T03:23:43Z

‎GLibc API

Comcat：以“== GLibc API == #include int sched_setaffinity(pid_t pid, unsigned int cpusetsize, cpu_set_t...”为内容创建页面

2017-10-30T03:23:26Z

以“== GLibc API == <source lang=cpp> #include <sched.h> int sched_setaffinity(pid_t pid, unsigned int cpusetsize, cpu_set_t...”为内容创建页面

新页面

== GLibc API ==

<source lang=cpp>
#include <sched.h>

int sched_setaffinity(pid_t pid, unsigned int cpusetsize,
cpu_set_t *mask);

int sched_getaffinity(pid_t pid, unsigned int cpusetsize,
cpu_set_t *mask);
</source>

Example:

<source lang=cpp>
unsigned int cpu_mask;
unsigned int pid = 1;
unsigned int mask = 0x1; // 绑定到 CPU0，0x2 则绑定到 CPU1

if (sched_getaffinity (pid, 4, &mask) < 0)
fprintf (stderr, "failed to get cpu affinity: %s\n", strerror (errno));
else
{
printf ("setting cpu affinity of pid=%d to %x\n", pid, cpu_mask);
if (sched_setaffinity (pid, 4, &cpu_mask) < 0)
fprintf (stderr, "failed to get cpu affinity: %s\n", strerror (errno));
else
if (sched_getaffinity (pid, 4, &mask) < 0)
fprintf (stderr, "failed to get cpu affinity: %s\n", strerror (errno));
else
printf ("cpu affinity of pid=%d is %x\n", pid, mask);
}
</source>

Other macros to manipulate the bitset (set, reset bits):

<source lang=bash>
void CPU_CLR(int cpu, cpu_set_t *set);
int CPU_ISSET(int cpu, cpu_set_t *set);
void CPU_SET(int cpu, cpu_set_t *set);
void CPU_ZERO(cpu_set_t *set);
</source>

Reference:

* http://www.gnu.org/software/libc/manual/html_node/CPU-Affinity.html

 

== Kernel interface (CPU Sets) ==

运行一个无限循环程序 setaffinity_test (pid = 22580)，top 的输出为：

<source lang=bash>
......
Cpu0 : 24.1%us, 0.3%sy, 0.0%ni, 96.4%id, 0.0%wa, 0.0%hi, 0.0%si, 0.0%st
Cpu1 : 77.8%us, 0.0%sy, 0.0%ni, 0.0%id, 0.0%wa, 0.0%hi, 0.0%si, 0.0%st
Mem: 2033068k total, 1120456k used, 912612k free, 17348k buffers
Swap: 0k total, 0k used, 0k free, 125876k cached
PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+COMMAND
22580 comcat 25 0 1496 312 252 R 100 0.0 2:54.74 setaffinity_test
......
</source>

其 status 为：

<source lang=bash>
$ cat /proc/22580/status | grep allow
Cpus_allowed: 03 ----------> 可运行于 CPU0 和 CPU1
Mems_allowed: 1

$ mkdir /dev/cpuset
$ mount -t cpuset x /dev/cpuset
$ cd /dev/cpuset
$ mkdir my_cpuset && cd my_cpuset # 创建自己的设置
$ echo 1 > cpus # 绑定到 CPU1
$ echo 0 > mems
$ echo 22580 > tasks # 让 pid 为 22580 的进程绑定到 CPU1
</source>

cpuset 设置后，top 的输出为：

<source lang=bash>
......
Cpu0 : 3.3%us, 0.3%sy, 0.0%ni, 96.4%id, 0.0%wa, 0.0%hi, 0.0%si, 0.0%st
Cpu1 : 100%us, 0.0%sy, 0.0%ni, 0.0%id, 0.0%wa, 0.0%hi, 0.0%si, 0.0%st
Mem: 2033068k total, 1120456k used, 912612k free, 17348k buffers
Swap: 0k total, 0k used, 0k free, 125876k cached
PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+COMMAND
22703 comcat 25 0 1496 312 252 R 100 0.0 2:54.74 setaffinity_test
......
</source>

此时其 status 为：

<source lang=bash>
$ cat /proc/22580/status | grep allow
Cpus_allowed: 02 ----------> 只可运行于 CPU1
Mems_allowed: 1
</source>

 

== Reference ==

* http://www.bullopensource.org/cpuset/
* http://www.mjmwired.net/kernel/Documentation/cpusets.txt
* http://www.mjmwired.net/kernel/Documentation/cpu-hotplug.txt

←上一版本		2025年12月4日 (四) 06:37的版本
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	* http://www.mjmwired.net/kernel/Documentation/cpu-hotplug.txt		* http://www.mjmwired.net/kernel/Documentation/cpu-hotplug.txt

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@@ 第37行： / 第37行： @@
 Other macros to manipulate the bitset (set, reset bits):
-<source lang=bash>
+<source lang=cpp>
         void CPU_CLR(int cpu, cpu_set_t *set);
         int CPU_ISSET(int cpu, cpu_set_t *set);

Linux 下绑定进程到 CPU - 版本历史

Comcat：/* Reference */

Comcat：/* GLibc API */

Comcat：以“== GLibc API == #include int sched_setaffinity(pid_t pid, unsigned int cpusetsize, cpu_set_t...”为内容创建页面