OpenBSD dropped support in version 5.7, released in May 2015.The Linux kernel extends it to non–process-related data.The proc filesystem provides a method of communication between kernel space and user space. In Linux, it can also be used to obtain information about the kernel and to change certain kernel parameters at runtime ( sysctl).Many Unix-like operating systems support the proc filesystem, including Solaris, IRIX, Tru64 UNIX, BSD, Linux, IBM AIX, QNX, and Plan 9 from Bell Labs. The proc file system acts as an interface to internal data structures about running processes in the kernel. Typically, it is mapped to a mount point named /proc at boot time.
![]() ![]() /proc/PID/environ contains the names and values of the environment variables that affect the process. /proc/PID/cwd, a symlink to the current working directory of the process. /proc/PID/cmdline, the command that originally started the process. Each directory contains information about one process, including: Solaris 2.6 in 1996 introduced procfs2 from Roger Faulkner.Linux first added a /proc filesystem in v0.97.3, September 1992, and first began expanding it to non-process related data in v0.98.6, December 1992.As of 2020, the Linux implementation includes a directory for each running process, including kernel processes, in directories named /proc/PID, where PID is the process number. /proc/PID/mem, a binary image representing the process's virtual memory, can only be accessed by a ptrace'ing process. /proc/PID/maps, a text file containing information about mapped files and blocks (like heap and stack). /proc/PID/fdinfo, a directory containing entries which describe the position and flags for each open file descriptor. /proc/PID/fd, a directory containing a symbolic link for each open file descriptor. /proc/buddyinfo, information about the buddy algorithm that handles memory fragmentation. depending on the mode of power management (if at all), either directory, /proc/acpi or /proc/apm, which predate sysfs and contain various bits of information about the state of power management. /proc/PID/task, a directory containing hard links to any tasks that have been started by this (i.e.: the parent) process.(Users may obtain the PID with a utility such as pgrep, pidof or ps:$ ls -l /proc/ $(pgrep -n python3 )/fd # List all file descriptors of the most recently started `python3' process total 0 lrwx- 1 baldur baldur 64 12:31 0 -> /dev/pts/3 lrwx- 1 baldur baldur 64 12:31 1 -> /dev/pts/3 lrwx- 1 baldur baldur 64 12:31 2 -> /dev/pts/3 $ readlink /proc/ $(pgrep -n python3 )/exe # List executable used to launch the most recently started `python3' process /usr/bin/python3.8/proc also includes non-process-related system information, although in the 2.6 kernel much of that information moved to a separate pseudo-file system, sysfs, mounted under /sys: /proc/PID/status contains basic information about a process including its run state and memory usage. For most processes this will be a link to / unless the process is running in a chroot jail. /proc/cmdline, giving the boot options passed to the kernel /proc/fb, a list of the available framebuffers This has been largely superseded by sysfs under /sys/bus which is far more informative. Cubase pro 8 free downloadThe number of hyper-threads per CPU package can be calculated by siblings / CPU cores. On multi-core CPUs, /proc/cpuinfo contains the fields for "siblings" and "cpu cores" which represent the following calculation is applied: "siblings" = (HT per CPU package) * (# of cores per CPU package)"cpu cores" = (# of cores per CPU package)A CPU package means physical CPU which can have multiple cores ( single core for one, dual core for two, quad core for four).This allows a distinction between hyper-threading and dual-core, i.e. Processor : 1 vendor_id : AuthenticAMD cpu family : 16 model : 6 model name : AMD Athlon(tm) II X2 270 Processor stepping : 3 microcode : 0x10000c8 cpu MHz : 800.000 cache size : 1024 KB. It occurs as a side-effect of kernel timer calibration and yields highly varying values depending on CPU type, even at equal clock speeds.Processor : 0 vendor_id : AuthenticAMD cpu family : 16 model : 6 model name : AMD Athlon(tm) II X2 270 Processor stepping : 3 microcode : 0x10000c8 cpu MHz : 2000.000 cache size : 1024 KB. /proc/cpuinfo includes a value for " bogomips", frequently misconstrued as a measure of CPU speed, like a benchmark, but it does not actually measure any sensible (for end-users) value at all. /proc/diskstats, giving some information (including device numbers) for each of the logical disk devices /proc/devices, a list of character and block devices sorted by device ID but giving the major part of the /dev name too /proc/crypto, a list of available cryptographic modules For instance, a CPU package with siblings=2 and "cpu cores"=2 is a dual-core CPU but does not support hyper-threading. /proc/modules, one of the most important files in /proc, containing a list of the kernel modules currently loaded. /proc/meminfo, containing a summary of how the kernel is managing its memory. /proc/kmsg, holding messages output by the kernel /proc/interrupts, /proc/iomem, /proc/ioports and the directory /proc/irq, giving some details about the devices (physical or logical) using the various system resources a symbolic link to the current (traversing) process at /proc/self (i.e. /proc/scsi, giving information about any devices connected via a SCSI or RAID controller /proc/partitions, a list of the device-numbers, their size and /dev names which the kernel has identified as existing partitions /proc/net/, a directory containing useful information about the network stack, in particular /proc/net/nf_conntrack, which lists existing network connections (particularly useful for tracking routing when iptables FORWARD is used to redirect network connections) /proc/mounts, a symlink to self/mounts which contains a list of the currently mounted devices and their mount points (and which file system is in use and what mount options are in use).
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