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Diffstat (limited to 'man5/proc_pid_io.5')
-rw-r--r-- | man5/proc_pid_io.5 | 100 |
1 files changed, 0 insertions, 100 deletions
diff --git a/man5/proc_pid_io.5 b/man5/proc_pid_io.5 deleted file mode 100644 index 4ad79f5..0000000 --- a/man5/proc_pid_io.5 +++ /dev/null @@ -1,100 +0,0 @@ -.\" Copyright (C) 1994, 1995, Daniel Quinlan <quinlan@yggdrasil.com> -.\" Copyright (C) 2002-2008, 2017, Michael Kerrisk <mtk.manpages@gmail.com> -.\" Copyright (C) 2023, Alejandro Colomar <alx@kernel.org> -.\" -.\" SPDX-License-Identifier: GPL-3.0-or-later -.\" -.TH proc_pid_io 5 2024-03-18 "Linux man-pages 6.7" -.SH NAME -/proc/pid/io \- I/O statistics -.SH DESCRIPTION -.TP -.IR /proc/ pid /io " (since Linux 2.6.20)" -.\" commit 7c3ab7381e79dfc7db14a67c6f4f3285664e1ec2 -This file contains I/O statistics -for the process and its waited-for children, -for example: -.IP -.in +4n -.EX -.RB "#" " cat /proc/3828/io" -rchar: 323934931 -wchar: 323929600 -syscr: 632687 -syscw: 632675 -read_bytes: 0 -write_bytes: 323932160 -cancelled_write_bytes: 0 -.EE -.in -.IP -The fields are as follows: -.RS -.TP -.IR rchar ": characters read" -The number of bytes -returned by successful -.BR read (2) -and similar system calls. -.TP -.IR wchar ": characters written" -The number of bytes -returned by successful -.BR write (2) -and similar system calls. -.TP -.IR syscr ": read syscalls" -The number of "file read" system calls\[em]those from the -.BR read (2) -family, -.BR sendfile (2), -.BR copy_file_range (2), -and -.BR ioctl (2) -.BR BTRFS_IOC_ENCODED_READ [ _32 ] -(including when invoked by the kernel as part of other syscalls). -.TP -.IR syscw ": write syscalls" -The number of "file write" system calls\[em]those from the -.BR write (2) -family, -.BR sendfile (2), -.BR copy_file_range (2), -and -.BR ioctl (2) -.BR BTRFS_IOC_ENCODED_WRITE [ _32 ] -(including when invoked by the kernel as part of other syscalls). -.TP -.IR read_bytes ": bytes read" -The number of bytes really fetched from the storage layer. -This is accurate for block-backed filesystems. -.TP -.IR write_bytes ": bytes written" -The number of bytes really sent to the storage layer. -.TP -.IR cancelled_write_bytes : -The above statistics fail to account for truncation: -if a process writes 1 MB to a regular file and then removes it, -said 1 MB will not be written, but -.I will -have nevertheless been accounted as a 1 MB write. -This field represents the number of bytes "saved" from I/O writeback. -This can yield to having done negative I/O -if caches dirtied by another process are truncated. -.I cancelled_write_bytes -applies to I/O already accounted-for in -.IR write_bytes . -.RE -.IP -Permission to access this file is governed by -.BR ptrace (2) -access mode -.BR PTRACE_MODE_READ_FSCREDS . -.SH CAVEATS -These counters are not atomic: -on systems where 64-bit integer operations may tear, -a counter could be updated simultaneously with a read, -yielding an incorrect intermediate value. -.SH SEE ALSO -.BR getrusage (2), -.BR proc (5) |