proc(7s)

NAME | NAME | DESCRIPTION | FILES | ATTRIBUTES | SEE ALSO

NAME

proc- Provides access to the state of each process

NAME

proc - /proc

DESCRIPTION

The ChorusOS operating system provides a /proc file system derived from the FreeBSD 4.1 implementation of /proc. Due to major differences in the implementation of the two systems, only a subset of the FreeBSD /proc file system has been retained. However, due to enhancements of the process model introduced by the ChorusOS operating system, such as the support of multi-threaded processes, extensions have been introduced to reflect the multi-threaded nature of the processes.

Such a file system is usually mounted, by convention, under the /proc directory. This directory is then populated and depopulated dynamically and automatically depending upon the life cycle of the processes. Note that ChorusOS actors are not reflected in this file system. Upon process creation (using fork() or posix_spawn()) an entry whose name is derived from the process identifier is created in the /proc directory. This per-process entry is in turn a directory whose layout is almost identical from one process to another. Threads running in this process are also represented by a regular file in the /proc file system (on a basis of one-to-one correspondence).

The list of entries that are supported below each process are listed in the table below.

Entry	Description
/proc	Mount point
/proc/curproc	Symbolic link to the current process
/proc/xxx	Per-process directory (where xxx is the PID of the process)
/proc/xxx/file	Symbolic link to the executable file
/proc/xxx/stats	Per-process instrumentation
/proc/xxx/status	Process status information mostly used by ps(1)
/proc/xxx/threads/	Process threads directory
/proc/xxx/threads/tt	Per-thread directory (where tt is the id of the thread)
/proc/xxx/threads/tt/stats	Per-thread instrumentation

For each actor or process currently active on the system, the following information is made available to the C_OS via the stats file of the process directory in the /proc file system:

Function	Instrument Type	Description
process_virt_pages	Gauge (high threshold)	Number of virtual memory pages used by a process
process_phys_pages	Simple Gauge	Number of physical memory pages used by a process
process_lock_pages	Simple Gauge	Number of locked memory pages used by a process
open_files	Gauge (high threshold)	Current number of open file descriptors
internal_cpu	Counter	Cumulated (all threads) internal CPU usage in milliseconds (similar to user mode)
external_cpu	Counter	Cumulated (all threads) external CPU usage in milliseconds (similar to system mode)

For each thread currently active on the system, the following information is made available via the stats entry of the process directory in the /proc file system:

Function	Instrument Type	Description
internal_cpu	Counter	Internal CPU time spent in milliseconds (similar to user mode)
external_cpu	Counter	External CPU time spent in milliseconds (similar to supervisor mode)
waiting_cnt	Counter	Number of times the thread has been blocked

FILES

/proc

ATTRIBUTES

See attributes(5) for descriptions of the following attributes:

ATTRIBUTE TYPE	ATTRIBUTE VALUE
Interface Stability	Evolving

SEE ALSO

sysctl(1M), sysctl(3POSIX)

ChorusOS 5.0  Last Revised December 2001

NAME | NAME | DESCRIPTION | FILES | ATTRIBUTES | SEE ALSO