Add block histogram to zdb

The block histogram tracks the changes to psize, lsize and asize
both in the count of the number of blocks (by blocksize) and the
total length of all of the blocks for that blocksize.  It also
keeps a running total of the cumulative size of all of the blocks
up to each size to help determine the size of caching SSDs to be
added to zfs hardware deployments.

The block history counts and lengths are summarized in bins
which are powers of two. Even rows with counts of zero are printed.

This change is accessed by specifying one of two options:

zdb -bbb pool
zdb -Pbbb pool

The first version prints the table in fixed size columns.
The second prints in "parseable" output that can be placed into
a CSV file.

Fixed Column, nicenum output sample:
  block   psize                lsize                asize
   size   Count Length   Cum.  Count Length   Cum.  Count Length   Cum.
    512:  3.50K  1.75M  1.75M  3.43K  1.71M  1.71M  3.41K  1.71M  1.71M
     1K:  3.65K  3.67M  5.43M  3.43K  3.44M  5.15M  3.50K  3.51M  5.22M
     2K:  3.45K  6.92M  12.3M  3.41K  6.83M  12.0M  3.59K  7.26M  12.5M
     4K:  3.44K  13.8M  26.1M  3.43K  13.7M  25.7M  3.49K  14.1M  26.6M
     8K:  3.42K  27.3M  53.5M  3.41K  27.3M  53.0M  3.44K  27.6M  54.2M
    16K:  3.43K  54.9M   108M  3.50K  56.1M   109M  3.42K  54.7M   109M
    32K:  3.44K   110M   219M  3.41K   109M   218M  3.43K   110M   219M
    64K:  3.41K   218M   437M  3.41K   218M   437M  3.44K   221M   439M
   128K:  3.41K   437M   874M  3.70K   474M   911M  3.41K   437M   876M
   256K:  3.41K   874M  1.71G  3.41K   874M  1.74G  3.41K   874M  1.71G
   512K:  3.41K  1.71G  3.41G  3.41K  1.71G  3.45G  3.41K  1.71G  3.42G
     1M:  3.41K  3.41G  6.82G  3.41K  3.41G  6.86G  3.41K  3.41G  6.83G
     2M:      0      0  6.82G      0      0  6.86G      0      0  6.83G
     4M:      0      0  6.82G      0      0  6.86G      0      0  6.83G
     8M:      0      0  6.82G      0      0  6.86G      0      0  6.83G
    16M:      0      0  6.82G      0      0  6.86G      0      0  6.83G

Reviewed-by: Brian Behlendorf <[email protected]>
Signed-off-by: Robert E. Novak <[email protected]>
Closes: #9158 
Closes #10315 

3 files changed, 276 insertions, 2 deletions

diff --git a/tests/runfiles/common.run b/tests/runfiles/common.run
index d8c109eb7..765ffea8a 100644
--- a/tests/runfiles/common.run
+++ b/tests/runfiles/common.run
@@ -104,8 +104,9 @@ tags = ['functional', 'clean_mirror']
 
 [tests/functional/cli_root/zdb]
 tests = ['zdb_002_pos', 'zdb_003_pos', 'zdb_004_pos', 'zdb_005_pos',
-    'zdb_006_pos', 'zdb_args_neg', 'zdb_args_pos', 'zdb_checksum', 'zdb_decompress',
-    'zdb_object_range_neg', 'zdb_object_range_pos', 'zdb_display_block',
+    'zdb_006_pos', 'zdb_args_neg', 'zdb_args_pos',
+    'zdb_block_size_histogram', 'zdb_checksum', 'zdb_decompress',
+    'zdb_display_block', 'zdb_object_range_neg', 'zdb_object_range_pos',
     'zdb_objset_id']
 pre =
 post =
diff --git a/tests/zfs-tests/tests/functional/cli_root/zdb/Makefile.am b/tests/zfs-tests/tests/functional/cli_root/zdb/Makefile.am
index e332a91a8..3cf13f3ae 100644
--- a/tests/zfs-tests/tests/functional/cli_root/zdb/Makefile.am
+++ b/tests/zfs-tests/tests/functional/cli_root/zdb/Makefile.am
@@ -7,6 +7,7 @@ dist_pkgdata_SCRIPTS = \
 	zdb_006_pos.ksh \
 	zdb_args_neg.ksh \
 	zdb_args_pos.ksh \
+	zdb_block_size_histogram.ksh \
 	zdb_checksum.ksh \
 	zdb_decompress.ksh \
 	zdb_object_range_neg.ksh \
diff --git a/tests/zfs-tests/tests/functional/cli_root/zdb/zdb_block_size_histogram.ksh b/tests/zfs-tests/tests/functional/cli_root/zdb/zdb_block_size_histogram.ksh
new file mode 100755
index 000000000..0c949f983
--- /dev/null
+++ b/tests/zfs-tests/tests/functional/cli_root/zdb/zdb_block_size_histogram.ksh
@@ -0,0 +1,272 @@
+#!/bin/ksh -p
+
+#
+# This file and its contents are supplied under the terms of the
+# Common Development and Distribution License ("CDDL"), version 1.0.
+# You may only use this file in accordance with the terms of version
+# 1.0 of the CDDL.
+#
+# A full copy of the text of the CDDL should have accompanied this
+# source.  A copy of the CDDL is also available via the Internet at
+# http://www.illumos.org/license/CDDL.
+#
+
+#
+# Copyright (c) 2017 by Delphix. All rights reserved.
+# Copyright (c) 2020 by Lawrence Livermore National Security LLC.
+
+. $STF_SUITE/include/libtest.shlib
+
+
+#
+# DESCRIPTION:
+#	Create a pool and populate it with files of various
+#	recordsizes
+#
+# STRATEGY:
+#	1. Create pool
+#	2. Populate it
+#	3. Run zdb -Pbbb on pool
+#	4. Verify variance on blocksizes
+#
+function cleanup
+{
+	datasetexists $TESTPOOL && destroy_pool $TESTPOOL
+}
+
+SPA_MAXBLOCKSHIFT=24
+
+function histo_populate_test_pool
+{
+	if [ $# -ne 1 ]; then
+		log_note "histo_populate_test_pool: insufficient parameters"
+		log_fail "hptp: 1 requested $# received"
+	fi
+	typeset pool=$1
+
+	set -A recordsizes
+	typeset -i min_rsbits=9 #512
+	typeset -i max_rsbits=SPA_MAXBLOCKSHIFT #16 MiB
+	typeset -i sum_filesizes=0
+	re_number='^[0-9]+$'
+
+	let histo_pool_size=$(get_pool_prop size ${pool})
+	if [[ ! ${histo_pool_size} =~ ${re_number} ]]; then
+		log_fail "histo_pool_size is not numeric ${pool_size}"
+	fi
+	let max_pool_record_size=$(get_prop recordsize ${pool})
+	if [[ ! ${max_pool_record_size} =~ ${re_number} ]]; then
+		log_fail "hptp: max_pool_record_size is not numeric ${max_pool_record_size}"
+	fi
+
+	sum_filesizes=$(echo "2^21"|bc)
+	((min_pool_size=12*sum_filesizes))
+	if [ ${histo_pool_size} -lt ${min_pool_size} ]; then
+		log_note "hptp: Your pool size ${histo_pool_size}"
+		log_fail "hptp: is less than minimum ${min_pool_size}"
+	fi
+	this_ri=min_rsbits
+	file_num=0
+	total_count=0
+	###################
+	# generate 10% + 20% + 30% + 31% = 91% of the filespace
+	# attempting to use 100% will lead to no space left on device
+	# Heuristic testing showed that 91% was the practical upper
+	# bound on the default 4G zpool (mirrored) that is used in
+	# testing.
+	#
+	# In order to expedite testing, we will only fill 2G (of 4G)
+	# of the test pool.  You may want to modify this for
+	# standalone testing.
+	# 
+	# In filling only 50% of the pool, we create one object on
+	# each "pass" below to achieve multiple objects per record
+	# size.  Creating one file per object would lead to 
+	# excessive file creation time.
+	###################
+	# for pass in 10 20 30 31  # 91%
+	for pass in 20 20 10 # 50%
+	do
+		((thiscount=(((histo_pool_size*pass)/100)/sum_filesizes)))
+
+		((total_count+=thiscount))
+		for rb in $(seq ${min_rsbits} ${max_rsbits})
+		do
+			this_rs=$(echo "2^${rb}" | bc)
+			if [ ${this_rs} -gt ${max_pool_record_size} ]; then
+				continue
+			fi
+	
+			if [ ! -d /${pool}/B_${this_rs} ]; then
+				zfs create ${pool}/B_${this_rs}
+				zfs set recordsize=${this_rs} \
+				    ${pool}/B_${this_rs}
+			fi
+			####################
+			# Create the files in the devices and datasets
+			# of the right size.  The files are filled
+			# with random data to defeat the compression
+			#
+			# Note that the dd output is suppressed unless
+			# there are errors
+			####################
+
+			dd if=/dev/urandom \
+			    of=/${pool}/B_${this_rs}/file_${filenum} \
+			    bs=${this_rs} count=${thiscount} \
+			    iflag=fullblock 2>&1 | \
+			    egrep -v -e "records in" -e "records out" \
+				-e "bytes.*copied"
+			((filenum+=1))
+		done
+	done
+
+	####################
+	# Testing showed that on some devices, unless the pool is 
+	# synchronized, that the block counts will be below the 
+	# anticipated sizes since not all of the blocks will be flushed
+	# to the device.  This 'sync' command prevents that from 
+	# happening.
+	####################
+	log_must zpool sync ${pool}
+}
+function histo_check_test_pool
+{
+	if [ $# -ne 1 ]; then
+		log_note "histo_check_test_pool: insufficient parameters"
+		log_fail "hctp: 1 requested $# received"
+	fi	
+	typeset pool=$1
+
+	set -A recordsizes
+	set -A recordcounts
+	typeset -i rb
+	typeset -i min_rsbits=9 #512
+	typeset -i max_rsbits=SPA_MAXBLOCKSHIFT+1
+	typeset -i this_rs
+	typeset -i this_ri
+	typeset -i sum_filesizes=0
+	typeset dumped
+	typeset stripped
+
+	let histo_check_pool_size=$(get_pool_prop size ${pool})
+	if [[ ! ${histo_check_pool_size} =~ ${re_number} ]]; then
+		log_fail "histo_check_pool_size is not numeric ${histo_check_pool_size}"
+	fi
+	let max_pool_record_size=$(get_prop recordsize ${pool})
+	if [[ ! ${max_pool_record_size} =~ ${re_number} ]]; then
+		log_fail "hctp: max_pool_record_size is not numeric ${max_pool_record_size}"
+	fi
+
+	dumped="${TEST_BASE_DIR}/${pool}_dump.txt"
+	stripped="${TEST_BASE_DIR}/${pool}_stripped.txt"
+
+	zdb -Pbbb ${pool} | \
+	    tee ${dumped} | \
+	    sed -e '1,/^block[ 	][ 	]*psize[ 	][ 	]*lsize.*$/d' \
+	    -e '/^size[ 	]*Count/d' -e '/^$/,$d' \
+	    > ${stripped}
+
+	sum_filesizes=$(echo "2^21"|bc)
+
+	###################
+	# generate 10% + 20% + 30% + 31% = 91% of the filespace
+	# attempting to use 100% will lead to no space left on device
+	# attempting to use 100% will lead to no space left on device
+	# Heuristic testing showed that 91% was the practical upper
+	# bound on the default 4G zpool (mirrored) that is used in
+	# testing.
+	#
+	# In order to expedite testing, we will only fill 2G (of 4G)
+	# of the test pool.  You may want to modify this for
+	# standalone testing.
+	# 
+	# In filling only 50% of the pool, we create one object on
+	# each "pass" below to achieve multiple objects per record
+	# size.  Creating one file per object would lead to 
+	# excessive file creation time.
+	###################
+	# for pass in 10 20 30 31  # 91%
+	for pass in 20 20 10 # 50%
+	do
+		((thiscount=(((histo_check_pool_size*pass)/100)/sum_filesizes)))
+
+		for rb in $(seq ${min_rsbits} ${max_rsbits})
+		do
+			blksize=$(echo "2^$rb"|bc)
+			if [ $blksize -le $max_pool_record_size ]; then
+				((recordcounts[$blksize]+=thiscount))
+			fi
+		done
+	done
+
+	###################
+	# compare the above computed counts for blocks against
+	# lsize count.  Since some devices have a minimum hardware
+	# blocksize > 512, we cannot compare against the asize count.
+	# E.G., if the HWBlocksize = 4096, then the asize counts for
+	# 512, 1024 and 2048 will be zero and rolled up into the 
+	# 4096 blocksize count for asize.   For verification we stick
+	# to just lsize counts.
+	#
+	# The max_variance is hard-coded here at 10%.  testing so far
+	# has shown this to be in the range of 2%-8% so we leave a
+	# generous allowance... This might need changes in the future
+	###################
+	let max_variance=10
+	let fail_value=0
+	let error_count=0
+	log_note "Comparisons for ${pool}"
+	log_note "Bsize is the blocksize, Count is predicted value"
+	log_note "Bsize\tCount\tpsize\tlsize\tasize"
+	while read -r blksize pc pl pm lc ll lm ac al am
+	do
+		if [ $blksize -gt $max_pool_record_size ]; then
+			continue
+		fi
+		log_note \
+		    "$blksize\t${recordcounts[${blksize}]}\t$pc\t$lc\t$ac"
+
+		###################
+		# get the computer record count and compute the
+		# difference percentage in integer arithmetic
+		###################
+		rc=${recordcounts[${blksize}]}
+		((rclc=(rc-lc)<0?lc-rc:rc-lc)) # absolute value
+		((dp=(rclc*100)/rc))
+
+		###################
+		# Check against the allowed variance
+		###################
+		if [ $dp -gt ${max_variance} ]; then
+			log_note \
+			"Expected variance < ${max_variance}% observed ${dp}%"
+			if [ ${dp} -gt ${fail_value} ]; then
+				fail_value=${dp}
+				((error_count++))
+			fi
+		fi
+	done < ${stripped}
+	if [ ${fail_value} -gt 0 ]; then
+		if [ ${error_count} -eq 1 ]; then
+			log_note "hctp: There was ${error_count} error"
+		else
+			log_note "hctp:There were a total of ${error_count} errors"
+		fi
+		log_fail \
+		"hctp: Max variance of ${max_variance}% exceeded, saw ${fail_value}%"
+	fi
+}
+
+log_assert "Verify zdb -Pbbb (block histogram) works as expected"
+log_onexit cleanup
+verify_runnable "global"
+verify_disk_count "$DISKS" 2
+
+default_mirror_setup_noexit $DISKS
+
+histo_populate_test_pool $TESTPOOL
+
+histo_check_test_pool $TESTPOOL
+
+log_pass "Histogram for zdb"