Portable arc_summary reimplementation

arc_summary.sh

#!/bin/sh

# Copyright 2015-2022 Rivoreo

# Permission is hereby granted, free of charge, to any person obtaining
# a copy of this software and associated documentation files (the
# "Software"), to deal in the Software without restriction, including
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# the following conditions:

# The above copyright notice and this permission notice shall be
# included in all copies or substantial portions of the Software.

# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
# EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
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# NONINFRINGEMENT. IN NO EVENT SHALL THE COPYRIGHT HOLDERS BE LIABLE
# FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF
# CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
# WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.


# Based on arc_summary.pl by Ben Rockwood, the original copyright notice and license follows:

# Copyright (c) 2008, Ben Rockwood (benr@cuddletech.com)
# All rights reserved.
#
# Redistribution and use in source and binary forms, with or without modification, 
# are permitted provided that the following conditions are met:
#    * Redistributions of source code must retain the above copyright notice, this 
#	list of conditions and the following disclaimer.
#    * Redistributions in binary form must reproduce the above copyright notice, 
#	this list of conditions and the following disclaimer in the documentation 
#	and/or other materials provided with the distribution.
#    * Neither the name of the Ben Rockwood nor the names of its contributors may be 
#	used to endorse or promote products derived from this software without specific 
#	prior written permission.
#
# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS 
# OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY 
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# CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 
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# OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
#

if [ -x "`which kstat`" ]; then
	# Solaris
	read_kstat() {
		if [ $# != 3 ]; then
			#echo "Usage: read_kstat <module> <class> <name>" 1>&2
			echo "# ($#) != 3" 1>&2
			exit 2
		fi
		eval "`kstat -p -m $1 -c $2 -n $3 | sed -E -e \"/^$1:0:/!d\" -e 's/.+://' -e 's/[[:space:]]+/=/'`"
	}
elif [ -d /proc/spl/kstat/zfs ]; then
	# OpenZFS on Linux
	read_kstat() {
		if [ $# != 3 ]; then
			echo "# ($#) != 3" 1>&2
			exit 2
		fi
		eval "`sed -E -e 1,2d -e 's/ .+ /=/' /proc/spl/kstat/$1/$3`"
	}
elif [ -x "`which sysctl`" ]; then
	# BSD
	read_kstat() {
		if [ $# != 3 ]; then
			echo "# ($#) != 3" 1>&2
			exit 2
		fi
		eval "`sysctl -e kstat.$1.$2.$3 | sed -E 's/.+\\.//'`"
	}
else
	echo "No known method to read kstat" 1>&2
	exit 1
fi

set -e
set -u

read_kstat zfs misc arcstats

#### ARC Sizing ###############

echo "ARC Size:"
printf "	Current Size			%11u MiB\\n" $((size/1024/1024))
printf "	Target Size (Adaptive)		%11u MiB\\n" $((c/1024/1024))
printf "	Min Size (Hard Limit)		%11u MiB\\n" $((c_min/1024/1024))
printf "	Max Size (High Water)		%11u MiB\\n" $((c_max/1024/1024))
echo

echo "ARC Size Breakdown:"
printf "	Most Recently Used Cache Size	% 3u%% %6u MiB\\n" $((p*100/c)) $((p/1024/1024))
mfu_size=$((c-p))
printf "	Most Frequently Used Cache Size	% 3u%% %6u MiB\\n" $((mfu_size*100/c)) $((mfu_size/1024/1024))

echo
##################################


####### ARC Efficency #########################
total_accesses=$((hits+misses))
real_hits=$((mfu_hits+mru_hits))

echo "ARC Efficency:"
printf "	Total Cache Accesses		%15u\\n" $total_accesses
printf "	Cache Hit Ratio			%3d%% %10u\\n" $((hits*100/total_accesses)) $hits
printf "	Cache Miss Ratio		%3d%% %10u\\n" $((misses*100/total_accesses)) $misses
printf "	Actual Hit Ratio		%3d%% %10u\\n" $((real_hits*100/total_accesses)) $real_hits
echo

demand_data_total=$((demand_data_hits+demand_data_misses))
if [ $demand_data_total = 0 ]; then
	echo "	Data Demand Efficiency		NOT APPLICABLE"
else
	printf "	Data Demand Efficiency		%3u%%\\n" $((demand_data_hits*100/demand_data_total))
fi
prefetch_data_total=$((prefetch_data_hits+prefetch_data_misses))
if [ $prefetch_data_total = 0 ]; then
	echo "	Data Prefetch Efficiency	DISABLED"
else
	printf "	Data Prefetch Efficiency	%3u%%\\n" $((prefetch_data_hits*100/prefetch_data_total))
fi
echo

anon_hits=$((hits-(mfu_hits+mru_hits+mfu_ghost_hits+mru_ghost_hits)))
#[ $anon_hits -lt 0 ] && anon_hits=0
echo "	CACHE HITS BY CACHE LIST:"
printf "	  Anonymously Used		"
if [ $anon_hits -lt 0 ]; then
	echo " Counter Rolled"
else
	printf "%3u%% %10u\\n" $((anon_hits*100/hits)) $anon_hits
fi
printf "	  Most Recently Used		%3u%% %10u\\n" $((mru_hits*100/hits)) $mru_hits
printf "	  Most Frequently Used		%3u%% %10u\\n" $((mfu_hits*100/hits)) $mfu_hits
printf "	  Most Recently Used Ghost	%3u%% %10u\\n" $((mru_ghost_hits*100/hits)) $mru_ghost_hits
printf "	  Most Frequently Used Ghost	%3u%% %10u\\n" $((mfu_ghost_hits*100/hits)) $mfu_ghost_hits
echo

echo "	CACHE HITS BY DATA TYPE:"
printf "	  Demand Data			%3u%% %10u\\n" $((demand_data_hits*100/hits)) $demand_data_hits
printf "	  Prefetch Data			%3u%% %10u\\n" $((prefetch_data_hits*100/hits)) $prefetch_data_hits
printf "	  Demand Metadata		%3u%% %10u\\n" $((demand_metadata_hits*100/hits)) $demand_metadata_hits
printf "	  Prefetch Metadata		%3u%% %10u\\n" $((prefetch_metadata_hits*100/hits)) $prefetch_metadata_hits

echo "	CACHE MISSES BY DATA TYPE:"
printf "	  Demand Data			%3u%% %10u\\n" $((demand_data_misses*100/hits)) $demand_data_misses
printf "	  Prefetch Data			%3u%% %10u\\n" $((prefetch_data_misses*100/hits)) $prefetch_data_misses
printf "	  Demand Metadata		%3u%% %10u\\n" $((demand_metadata_misses*100/hits)) $demand_metadata_misses
printf "	  Prefetch Metadata		%3u%% %10u\\n" $((prefetch_metadata_misses*100/hits)) $prefetch_metadata_misses
echo