Add request size histograms (-r) to zpool iostat, minor man page fix

Add -r option to "zpool iostat" to print request size histograms for the leaf
ZIOs. This includes histograms of individual ZIOs ("ind") and aggregate ZIOs
("agg"). These stats can be useful for seeing how well the ZFS IO aggregator
is working.

$ zpool iostat -r
mypool        sync_read    sync_write    async_read    async_write      scrub
req_size      ind    agg    ind    agg    ind    agg    ind    agg    ind    agg
----------  -----  -----  -----  -----  -----  -----  -----  -----  -----  -----
512             0      0      0      0      0      0    530      0      0      0
1K              0      0    260      0      0      0    116    246      0      0
2K              0      0      0      0      0      0      0    431      0      0
4K              0      0      0      0      0      0      3    107      0      0
8K             15      0     35      0      0      0      0      6      0      0
16K             0      0      0      0      0      0      0     39      0      0
32K             0      0      0      0      0      0      0      0      0      0
64K            20      0     40      0      0      0      0      0      0      0
128K            0      0     20      0      0      0      0      0      0      0
256K            0      0      0      0      0      0      0      0      0      0
512K            0      0      0      0      0      0      0      0      0      0
1M              0      0      0      0      0      0      0      0      0      0
2M              0      0      0      0      0      0      0      0      0      0
4M              0      0      0      0      0      0    155     19      0      0
8M              0      0      0      0      0      0      0    811      0      0
16M             0      0      0      0      0      0      0     68      0      0
--------------------------------------------------------------------------------

Also rename the stray "-G" in the man page to be "-w" for latency histograms.

Signed-off-by: Tony Hutter <[email protected]>
Signed-off-by: Brian Behlendorf <[email protected]>
Signed-off-by: Tim Chase <[email protected]>
Closes #4659

2 files changed, 6 insertions, 3 deletions

diff --git a/tests/zfs-tests/tests/functional/cli_user/zpool_iostat/zpool_iostat_003_neg.ksh b/tests/zfs-tests/tests/functional/cli_user/zpool_iostat/zpool_iostat_003_neg.ksh
index ae1e5a152..097be9e74 100755
--- a/tests/zfs-tests/tests/functional/cli_user/zpool_iostat/zpool_iostat_003_neg.ksh
+++ b/tests/zfs-tests/tests/functional/cli_user/zpool_iostat/zpool_iostat_003_neg.ksh
@@ -52,7 +52,8 @@ fi
 
 set -A args "" "-?" "-f" "nonexistpool" "$TESTPOOL/$TESTFS" \
 	"$testpool 0" "$testpool -1" "$testpool 1 0" \
-	"$testpool 0 0" "$testpool -wl" "$testpool -wq"
+	"$testpool 0 0" "$testpool -wl" "$testpool -wq" "$testpool -wr" \
+	"$testpool -rq" "$testpool -lr"
 
 log_assert "Executing 'zpool iostat' with bad options fails"
 
diff --git a/tests/zfs-tests/tests/functional/cli_user/zpool_iostat/zpool_iostat_004_pos.ksh b/tests/zfs-tests/tests/functional/cli_user/zpool_iostat/zpool_iostat_004_pos.ksh
index f8bd8e3db..0119a7061 100755
--- a/tests/zfs-tests/tests/functional/cli_user/zpool_iostat/zpool_iostat_004_pos.ksh
+++ b/tests/zfs-tests/tests/functional/cli_user/zpool_iostat/zpool_iostat_004_pos.ksh
@@ -36,7 +36,7 @@
 #
 # DESCRIPTION:
 # Executing 'zpool iostat' command with various combinations of extended
-# stats (-vqL), parsable/script options (-pH), and misc lists of pools
+# stats (-lqwr), parsable/script options (-pH), and misc lists of pools
 # and vdevs.
 #
 # STRATEGY:
@@ -59,7 +59,9 @@ set -A args "" "-v" "-q" "-l" "-lq $TESTPOOL" "-ql ${DISKS[0]} ${DISKS[1]}" \
 	"-wp $TESTPOOL" \
 	"-qlH $TESTPOOL ${DISKS[0]}" \
 	"-vpH ${DISKS[0]}" \
-	"-wpH ${DISKS[0]}"
+	"-wpH ${DISKS[0]}" \
+	"-r ${DISKS[0]}" \
+	"-rpH ${DISKS[0]}"
 
 log_assert "Executing 'zpool iostat' with extended stat options succeeds"
 log_note "testpool: $TESTPOOL, disks $DISKS"