watch_raw_io

#! /bin/bash

#----------------------------------------------------------------------
# Description: watch raw input output per block device stats in real time
# Author: Artem S. Tashkinov
# Created at: Sat Apr  6 18:34:33 2013
# Computer: localhost.localdomain
# System: Linux 3.8.7-ic on i686
#
# Copyright (c) 2013 Artem S. Tashkinov  All rights reserved.
# Sat Aug 24 19:59:32 2013 - implemented read/write interval counters
# Sun Aug 25 23:51:14 2013 - made refreshing three times faster
# Thu Feb  4 18:59:41 2016 - exit on pressing q/Q, read refresh rate from console
# 2020-03-27 18:04:40 - fix finding the root in /proc/cmdline - remove an extra space, add -w instead
#                     - sort devices numerically
# 2021-10-23 04:51:04 - add nvme support
#
#----------------------------------------------------------------------

shopt -s nullglob
export LANG=en_US.UTF-8
rr=2

trap "exit 0" TERM
export TOP_PID=$$

qexit()
{
	read -n 1 -t 0.5 -s char
	if [ "$char" = "q" -o "$char" = "Q" ]; then
		echo "Bye"
		kill -s TERM $TOP_PID
	fi
}

if [ -n "$1" ]; then
	if [ "$1" -eq "$1" ] 2>/dev/null; then
		rr="$1"
	else
		echo "[$1] is not a number, setting refresh rate to $rr"
		sleep 3
	fi
fi

dsrc=/sys/block
cd $dsrc || die "$dsrc not found"

declare -A intr intw blkr blkw

while :; do
	clear
	date | tr -d '\n'
	echo "			[ refresh rate: ${rr} seconds ]"
	echo "Device         Read bytes       Written bytes   Interval read Interval written Mount point"
	for i in sd* md* nvme*; do # adjust for your environment
#		for j in $i/$i* $i; do
		for j in $i/$i[0-9] $i/$i[0-9][0-9] $i/$i[0-9][0-9][0-9] $i/nvme*n*p* $i; do # at most 999 partitions
			dev=${j##*/}
			test -z "$dev" && dev="$j" # when iterating $i itself

			read blkr blkw < <(awk '{print $3" "$7}' $j/stat) # let's speed up this a bit
			blkr["$dev"]=$blkr
			blkw["$dev"]=$blkw

			test -z "${intr[$dev]}" && intr[$dev]=0
			test -z "${intw[$dev]}" && intw[$dev]=0
			intr[$dev]=$((${blkr[$dev]}-${intr[$dev]}))
			intw[$dev]=$((${blkw[$dev]}-${intw[$dev]}))
			test "${blkr[$dev]}" == "${intr[$dev]}" && intr[$dev]=0 # Don't show when iterating for the first time
			test "${blkw[$dev]}" == "${intw[$dev]}" && intw[$dev]=0

			printf "%-10s %'17d   %'17d  %'14d   %'14d " $dev $((blkr[$dev]*512)) $((blkw[$dev]*512)) $((intr[$dev]*512)) $((intw[$dev]*512))

			mntp=`awk '/^\/dev\/'$dev' /{print $2}' /proc/mounts`
			if [ -z "$mntp" ]; then # FIXME: this won't work for partitons mounted via UUID/LABEL
				grep -qw "root=/dev/$dev" /proc/cmdline && mntp="/"
			fi
			echo "$mntp"

			intr["$dev"]=${blkr["$dev"]}
			intw["$dev"]=${blkw["$dev"]}
		done
		echo
	done
	qexit < /dev/stdin &
	sleep $rr
done