Merge branch 'kstat'

This branch updates several of the zfs kstats to take advantage
of the improved raw kstat functionality.  In addition, two new
kstats and a script called dbufstat.py are introduced.

Updated+New Kstats
* dbufs        - Stats for all dbufs in the dbuf_hash
* <pool>/txgs  - Stats for the last N txgs synced to disk
* <pool>/reads - Stats for rhe last N reads issues by the ARC
* <pool>/dmu_tx_assign - Histogram of tx assign times

Signed-off-by: Brian Behlendorf <[email protected]>

cmd/Makefile.am

@@ -1,2 +1,2 @@
 SUBDIRS  = zfs zpool zdb zhack zinject zstreamdump ztest zpios
-SUBDIRS += mount_zfs fsck_zfs zvol_id vdev_id arcstat
+SUBDIRS += mount_zfs fsck_zfs zvol_id vdev_id arcstat dbufstat

cmd/arcstat/arcstat.py

@@ -106,7 +106,7 @@
 sep = "  "              # Default separator is 2 spaces
 version = "0.4"
 l2exist = False
-cmd = ("Usage: arcstat [-hvx] [-f fields] [-o file] [-s string] [interval "
+cmd = ("Usage: arcstat.py [-hvx] [-f fields] [-o file] [-s string] [interval "
     "[count]]\n")
 cur = {}
 d = {}
@@ -136,10 +136,10 @@ def usage():
     sys.stderr.write("\t -s : Override default field separator with custom "
         "character or string\n")
     sys.stderr.write("\nExamples:\n")
-    sys.stderr.write("\tarcstat -o /tmp/a.log 2 10\n")
-    sys.stderr.write("\tarcstat -s \",\" -o /tmp/a.log 2 10\n")
-    sys.stderr.write("\tarcstat -v\n")
-    sys.stderr.write("\tarcstat -f time,hit%,dh%,ph%,mh% 1\n")
+    sys.stderr.write("\tarcstat.py -o /tmp/a.log 2 10\n")
+    sys.stderr.write("\tarcstat.py -s \",\" -o /tmp/a.log 2 10\n")
+    sys.stderr.write("\tarcstat.py -v\n")
+    sys.stderr.write("\tarcstat.py -f time,hit%,dh%,ph%,mh% 1\n")
     sys.stderr.write("\n")
 
     sys.exit(1)

cmd/dbufstat/Makefile.am

@@ -0,0 +1,2 @@
+bin_SCRIPTS = dbufstat.py
+EXTRA_DIST = $(bin_SCRIPTS)