在Linux中如何将服务绑定在某个CPU内核上运行？

如果服务是多线程服务，那么它可能会根据线程的可用性在多个核心上运行，
如果该服务在单个核心上运行，则每次重新启动服务时它将在不同的线程上运行，但至少它会继续使用单线程直到该服务重新启动。

在 Linux 中如何找出进程运行在哪个CPU核心上

如何将指定的CPU核心分配给服务？

例如我有一个 test.service

# systemctl status test.service
â test.service - LSB: start any SW, when required
   Loaded: loaded (/etc/rc.d/init.d/test; enabled; vendor preset: disabled)
   Active: active (exited) since Sun 2015-01-21 00:04:55 IST; 31s ago
     Docs: man:systemd-sysv-generator(8)
  Process: 22045 ExecStop=/etc/rc.d/init.d/test stop (code=exited, status=0/SUCCESS)
  Process: 22066 ExecStart=/etc/rc.d/init.d/test start (code=exited, status=0/SUCCESS)

使用以下命令，我们可以检查它正在使用的核心

# grep -i cpu  /proc/2206?/status
Cpus_allowed:   1000
Cpus_allowed_list:      12

现在，如果我重新启动 servcie 并检查服务的 PID，我们将观察到核心编号很可能会发生变化

# systemctl status test.service
â test.service - LSB: start any SW, when required
   Loaded: loaded (/etc/rc.d/init.d/test; enabled; vendor preset: disabled)
   Active: active (exited) since Sun 2015-01-21 00:06:07 IST; 7s ago
     Docs: man:systemd-sysv-generator(8)
  Process: 22290 ExecStop=/etc/rc.d/init.d/test stop (code=exited, status=0/SUCCESS)
  Process: 22312 ExecStart=/etc/rc.d/init.d/test start (code=exited, status=0/SUCCESS)

正如我们之前看到的，此服务在第 12 个核心上运行，现在它在第 6 个核心上运行。

# grep -i cpu  /proc/2231?/status
Cpus_allowed:   0040
Cpus_allowed_list:      6

将此服务分配给我们希望始终运行的核心

# vim /etc/systemd/system/test.service
...
[Service]
CPUAffinity=13
Type=forking
Restart=no
...

由于我们修改了单元文件我们必须在重新启动服务之前刷新配置

# systemctl daemon-reload
# systemctl restart test.service

接下来检查服务的状态和PID

# systemctl status test.service
â test.service - LSB: start any SW, when required
   Loaded: loaded (/etc/rc.d/init.d/test; enabled; vendor preset: disabled)
   Active: active (exited) since Sun 2015-01-21 00:01:51 IST; 2s ago
     Docs: man:systemd-sysv-generator(8)
  Process: 21944 ExecStop=/etc/rc.d/init.d/test stop (code=exited, status=0/SUCCESS)
  Process: 21966 ExecStart=/etc/rc.d/init.d/test start (code=exited, status=0/SUCCESS)

正如预期的那样，现在该服务正在分配的核心上运行，

# grep -i cpu  /proc/2196?/status
Cpus_allowed:   2000
Cpus_allowed_list:      13

让我们把它改成不同的核心编号

# vim /etc/systemd/system/test.service
...
[Service]
CPUAffinity=15
Type=forking
Restart=no
...

接着是重新加载单元配置文件并重启各自的服务

# systemctl daemon-reload
# systemctl restart test.service

接下来检查服务的状态和PID

# systemctl status test.service
â test.service - LSB: start any SW, when required
   Loaded: loaded (/etc/rc.d/init.d/test; enabled; vendor preset: disabled)
   Active: active (exited) since Sat 2015-01-20 23:59:14 IST; 13s ago
     Docs: man:systemd-sysv-generator(8)
  Process: 21760 ExecStop=/etc/rc.d/init.d/test stop (code=exited, status=0/SUCCESS)
  Process: 21782 ExecStart=/etc/rc.d/init.d/test start (code=exited, status=0/SUCCESS)

使用以下命令，我们获取运行此测试服务的核心，并按预期在第 15 个核心上运行

# grep -i cpu  /proc/2178?/status
Cpus_allowed:   8000
Cpus_allowed_list:      15