在Emacs中获取CPU核的数量
从 Counting Processor Cores in Emacs 这里看到的,记录一下
在linux/cygwin下获取CPU核的数量
linux/cygwin提供了 /proc 虚拟文件系统可以获取系统信息,具体来说,在 /proc/cpuinfo 中会列出所有CPU核的信息
(when (file-exists-p "/proc/cpuinfo") (with-temp-buffer (insert-file-contents "/proc/cpuinfo") (how-many "^processor[[:space:]]+:")))
2
在Windows下获取CPU核的数量
Windows提供了一个名为 NUMBER_OF_PROCESSORS 的环境变量,里面存的就是核的数量
(let ((number-of-processors (getenv "NUMBER_OF_PROCESSORS"))) (when number-of-processors (string-to-number number-of-processors)))
在BSD/OSX下获取CPU核的数量
需要调用 sysctl 来获取
(with-temp-buffer (ignore-errors (when (zerop (call-process "sysctl" nil t nil "-n" "hw.ncpu")) (string-to-number (buffer-string)))))
综合起来
通过变量 system-type 可以获得操作系统的类型,不同操作系统调用不同的方法来获取CPU核的数量
(defun numcores () "Return number of cores" (case system-type ((gnu/linux cygwin) (when (file-exists-p "/proc/cpuinfo") (with-temp-buffer (insert-file-contents "/proc/cpuinfo") (how-many "^processor[[:space:]]+:"))) ) ((gnu/kfreebsd darwin) (with-temp-buffer (ignore-errors (when (zerop (call-process "sysctl" nil t nil "-n" "hw.ncpu")) (string-to-number (buffer-string))))) ) ((windows-nt) (let ((number-of-processors (getenv "NUMBER_OF_PROCESSORS"))) (when number-of-processors (string-to-number number-of-processors))) )))
