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freebsd-nq/cmd/arcstat/arcstat.in
George Amanakis 085321621e
Add L2ARC arcstats for MFU/MRU buffers and buffer content type 
Currently the ARC state (MFU/MRU) of cached L2ARC buffer and their
content type is unknown. Knowing this information may prove beneficial
in adjusting the L2ARC caching policy.

This commit adds L2ARC arcstats that display the aligned size
(in bytes) of L2ARC buffers according to their content type
(data/metadata) and according to their ARC state (MRU/MFU or
prefetch). It also expands the existing evict_l2_eligible arcstat to
differentiate between MFU and MRU buffers.

L2ARC caches buffers from the MRU and MFU lists of ARC. Upon caching a
buffer, its ARC state (MRU/MFU) is stored in the L2 header
(b_arcs_state). The l2_m{f,r}u_asize arcstats reflect the aligned size
(in bytes) of L2ARC buffers according to their ARC state (based on
b_arcs_state). We also account for the case where an L2ARC and ARC
cached MRU or MRU_ghost buffer transitions to MFU. The l2_prefetch_asize
reflects the alinged size (in bytes) of L2ARC buffers that were cached
while they had the prefetch flag set in ARC. This is dynamically updated
as the prefetch flag of L2ARC buffers changes.

When buffers are evicted from ARC, if they are determined to be L2ARC
eligible then their logical size is recorded in
evict_l2_eligible_m{r,f}u arcstats according to their ARC state upon
eviction.

Persistent L2ARC:
When committing an L2ARC buffer to a log block (L2ARC metadata) its
b_arcs_state and prefetch flag is also stored. If the buffer changes
its arcstate or prefetch flag this is reflected in the above arcstats.
However, the L2ARC metadata cannot currently be updated to reflect this
change.
Example: L2ARC caches an MRU buffer. L2ARC metadata and arcstats count
this as an MRU buffer. The buffer transitions to MFU. The arcstats are
updated to reflect this. Upon pool re-import or on/offlining the L2ARC
device the arcstats are cleared and the buffer will now be counted as an
MRU buffer, as the L2ARC metadata were not updated.

Bug fix:
- If l2arc_noprefetch is set, arc_read_done clears the L2CACHE flag of
  an ARC buffer. However, prefetches may be issued in a way that
  arc_read_done() is bypassed. Instead, move the related code in
  l2arc_write_eligible() to account for those cases too.

Also add a test and update manpages for l2arc_mfuonly module parameter,
and update the manpages and code comments for l2arc_noprefetch.
Move persist_l2arc tests to l2arc.

Reviewed-by: Ryan Moeller <freqlabs@FreeBSD.org>
Reviewed-by: Richard Elling <Richard.Elling@RichardElling.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: George Amanakis <gamanakis@gmail.com>
Closes #10743
2020-09-14 10:10:44 -07:00

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#!/usr/bin/env @PYTHON_SHEBANG@
#
# Print out ZFS ARC Statistics exported via kstat(1)
# For a definition of fields, or usage, use arcstat -v
#
# This script was originally a fork of the original arcstat.pl (0.1)
# by Neelakanth Nadgir, originally published on his Sun blog on
# 09/18/2007
# http://blogs.sun.com/realneel/entry/zfs_arc_statistics
#
# A new version aimed to improve upon the original by adding features
# and fixing bugs as needed. This version was maintained by Mike
# Harsch and was hosted in a public open source repository:
# http://github.com/mharsch/arcstat
#
# but has since moved to the illumos-gate repository.
#
# This Python port was written by John Hixson for FreeNAS, introduced
# in commit e2c29f:
# https://github.com/freenas/freenas
#
# and has been improved by many people since.
#
# CDDL HEADER START
#
# The contents of this file are subject to the terms of the
# Common Development and Distribution License, Version 1.0 only
# (the "License"). You may not use this file except in compliance
# with the License.
#
# You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
# or http://www.opensolaris.org/os/licensing.
# See the License for the specific language governing permissions
# and limitations under the License.
#
# When distributing Covered Code, include this CDDL HEADER in each
# file and include the License file at usr/src/OPENSOLARIS.LICENSE.
# If applicable, add the following below this CDDL HEADER, with the
# fields enclosed by brackets "[]" replaced with your own identifying
# information: Portions Copyright [yyyy] [name of copyright owner]
#
# CDDL HEADER END
#
#
# Fields have a fixed width. Every interval, we fill the "v"
# hash with its corresponding value (v[field]=value) using calculate().
# @hdr is the array of fields that needs to be printed, so we
# just iterate over this array and print the values using our pretty printer.
#
# This script must remain compatible with Python 2.6+ and Python 3.4+.
#
import sys
import time
import getopt
import re
import copy
from signal import signal, SIGINT, SIGWINCH, SIG_DFL
cols = {
# HDR: [Size, Scale, Description]
"time": [8, -1, "Time"],
"hits": [4, 1000, "ARC reads per second"],
"miss": [4, 1000, "ARC misses per second"],
"read": [4, 1000, "Total ARC accesses per second"],
"hit%": [4, 100, "ARC hit percentage"],
"miss%": [5, 100, "ARC miss percentage"],
"dhit": [4, 1000, "Demand hits per second"],
"dmis": [4, 1000, "Demand misses per second"],
"dh%": [3, 100, "Demand hit percentage"],
"dm%": [3, 100, "Demand miss percentage"],
"phit": [4, 1000, "Prefetch hits per second"],
"pmis": [4, 1000, "Prefetch misses per second"],
"ph%": [3, 100, "Prefetch hits percentage"],
"pm%": [3, 100, "Prefetch miss percentage"],
"mhit": [4, 1000, "Metadata hits per second"],
"mmis": [4, 1000, "Metadata misses per second"],
"mread": [5, 1000, "Metadata accesses per second"],
"mh%": [3, 100, "Metadata hit percentage"],
"mm%": [3, 100, "Metadata miss percentage"],
"arcsz": [5, 1024, "ARC size"],
"size": [4, 1024, "ARC size"],
"c": [4, 1024, "ARC target size"],
"mfu": [4, 1000, "MFU list hits per second"],
"mru": [4, 1000, "MRU list hits per second"],
"mfug": [4, 1000, "MFU ghost list hits per second"],
"mrug": [4, 1000, "MRU ghost list hits per second"],
"eskip": [5, 1000, "evict_skip per second"],
"el2skip": [7, 1000, "evict skip, due to l2 writes, per second"],
"el2cach": [7, 1024, "Size of L2 cached evictions per second"],
"el2el": [5, 1024, "Size of L2 eligible evictions per second"],
"el2mfu": [6, 1024, "Size of L2 eligible MFU evictions per second"],
"el2mru": [6, 1024, "Size of L2 eligible MRU evictions per second"],
"el2inel": [7, 1024, "Size of L2 ineligible evictions per second"],
"mtxmis": [6, 1000, "mutex_miss per second"],
"dread": [5, 1000, "Demand accesses per second"],
"pread": [5, 1000, "Prefetch accesses per second"],
"l2hits": [6, 1000, "L2ARC hits per second"],
"l2miss": [6, 1000, "L2ARC misses per second"],
"l2read": [6, 1000, "Total L2ARC accesses per second"],
"l2hit%": [6, 100, "L2ARC access hit percentage"],
"l2miss%": [7, 100, "L2ARC access miss percentage"],
"l2pref": [6, 1024, "L2ARC prefetch allocated size"],
"l2mfu": [5, 1024, "L2ARC MFU allocated size"],
"l2mru": [5, 1024, "L2ARC MRU allocated size"],
"l2data": [6, 1024, "L2ARC data allocated size"],
"l2meta": [6, 1024, "L2ARC metadata allocated size"],
"l2pref%": [7, 100, "L2ARC prefetch percentage"],
"l2mfu%": [6, 100, "L2ARC MFU percentage"],
"l2mru%": [6, 100, "L2ARC MRU percentage"],
"l2data%": [7, 100, "L2ARC data percentage"],
"l2meta%": [7, 100, "L2ARC metadata percentage"],
"l2asize": [7, 1024, "Actual (compressed) size of the L2ARC"],
"l2size": [6, 1024, "Size of the L2ARC"],
"l2bytes": [7, 1024, "Bytes read per second from the L2ARC"],
"grow": [4, 1000, "ARC grow disabled"],
"need": [4, 1024, "ARC reclaim need"],
"free": [4, 1024, "ARC free memory"],
"avail": [5, 1024, "ARC available memory"],
"waste": [5, 1024, "Wasted memory due to round up to pagesize"],
}
v = {}
hdr = ["time", "read", "miss", "miss%", "dmis", "dm%", "pmis", "pm%", "mmis",
"mm%", "size", "c", "avail"]
xhdr = ["time", "mfu", "mru", "mfug", "mrug", "eskip", "mtxmis", "dread",
"pread", "read"]
sint = 1 # Default interval is 1 second
count = 1 # Default count is 1
hdr_intr = 20 # Print header every 20 lines of output
opfile = None
sep = " " # Default separator is 2 spaces
version = "0.4"
l2exist = False
cmd = ("Usage: arcstat [-hvx] [-f fields] [-o file] [-s string] [interval "
"[count]]\n")
cur = {}
d = {}
out = None
kstat = None
if sys.platform.startswith('freebsd'):
# Requires py27-sysctl on FreeBSD
import sysctl
def kstat_update():
global kstat
k = sysctl.filter('kstat.zfs.misc.arcstats')
if not k:
sys.exit(1)
kstat = {}
for s in k:
if not s:
continue
name, value = s.name, s.value
# Trims 'kstat.zfs.misc.arcstats' from the name
kstat[name[24:]] = int(value)
elif sys.platform.startswith('linux'):
def kstat_update():
global kstat
k = [line.strip() for line in open('/proc/spl/kstat/zfs/arcstats')]
if not k:
sys.exit(1)
del k[0:2]
kstat = {}
for s in k:
if not s:
continue
name, unused, value = s.split()
kstat[name] = int(value)
def detailed_usage():
sys.stderr.write("%s\n" % cmd)
sys.stderr.write("Field definitions are as follows:\n")
for key in cols:
sys.stderr.write("%11s : %s\n" % (key, cols[key][2]))
sys.stderr.write("\n")
sys.exit(0)
def usage():
sys.stderr.write("%s\n" % cmd)
sys.stderr.write("\t -h : Print this help message\n")
sys.stderr.write("\t -v : List all possible field headers and definitions"
"\n")
sys.stderr.write("\t -x : Print extended stats\n")
sys.stderr.write("\t -f : Specify specific fields to print (see -v)\n")
sys.stderr.write("\t -o : Redirect output to the specified file\n")
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("\n")
sys.exit(1)
def snap_stats():
global cur
global kstat
prev = copy.deepcopy(cur)
kstat_update()
cur = kstat
for key in cur:
if re.match(key, "class"):
continue
if key in prev:
d[key] = cur[key] - prev[key]
else:
d[key] = cur[key]
def prettynum(sz, scale, num=0):
suffix = [' ', 'K', 'M', 'G', 'T', 'P', 'E', 'Z']
index = 0
save = 0
# Special case for date field
if scale == -1:
return "%s" % num
# Rounding error, return 0
elif 0 < num < 1:
num = 0
while abs(num) > scale and index < 5:
save = num
num = num / scale
index += 1
if index == 0:
return "%*d" % (sz, num)
if abs(save / scale) < 10:
return "%*.1f%s" % (sz - 1, num, suffix[index])
else:
return "%*d%s" % (sz - 1, num, suffix[index])
def print_values():
global hdr
global sep
global v
sys.stdout.write(sep.join(
prettynum(cols[col][0], cols[col][1], v[col]) for col in hdr))
sys.stdout.write("\n")
sys.stdout.flush()
def print_header():
global hdr
global sep
sys.stdout.write(sep.join("%*s" % (cols[col][0], col) for col in hdr))
sys.stdout.write("\n")
def get_terminal_lines():
try:
import fcntl
import termios
import struct
data = fcntl.ioctl(sys.stdout.fileno(), termios.TIOCGWINSZ, '1234')
sz = struct.unpack('hh', data)
return sz[0]
except Exception:
pass
def update_hdr_intr():
global hdr_intr
lines = get_terminal_lines()
if lines and lines > 3:
hdr_intr = lines - 3
def resize_handler(signum, frame):
update_hdr_intr()
def init():
global sint
global count
global hdr
global xhdr
global opfile
global sep
global out
global l2exist
desired_cols = None
xflag = False
hflag = False
vflag = False
i = 1
try:
opts, args = getopt.getopt(
sys.argv[1:],
"xo:hvs:f:",
[
"extended",
"outfile",
"help",
"verbose",
"separator",
"columns"
]
)
except getopt.error as msg:
sys.stderr.write("Error: %s\n" % str(msg))
usage()
opts = None
for opt, arg in opts:
if opt in ('-x', '--extended'):
xflag = True
if opt in ('-o', '--outfile'):
opfile = arg
i += 1
if opt in ('-h', '--help'):
hflag = True
if opt in ('-v', '--verbose'):
vflag = True
if opt in ('-s', '--separator'):
sep = arg
i += 1
if opt in ('-f', '--columns'):
desired_cols = arg
i += 1
i += 1
argv = sys.argv[i:]
sint = int(argv[0]) if argv else sint
count = int(argv[1]) if len(argv) > 1 else (0 if len(argv) > 0 else 1)
if hflag or (xflag and desired_cols):
usage()
if vflag:
detailed_usage()
if xflag:
hdr = xhdr
update_hdr_intr()
# check if L2ARC exists
snap_stats()
l2_size = cur.get("l2_size")
if l2_size:
l2exist = True
if desired_cols:
hdr = desired_cols.split(",")
invalid = []
incompat = []
for ele in hdr:
if ele not in cols:
invalid.append(ele)
elif not l2exist and ele.startswith("l2"):
sys.stdout.write("No L2ARC Here\n%s\n" % ele)
incompat.append(ele)
if len(invalid) > 0:
sys.stderr.write("Invalid column definition! -- %s\n" % invalid)
usage()
if len(incompat) > 0:
sys.stderr.write("Incompatible field specified! -- %s\n" %
incompat)
usage()
if opfile:
try:
out = open(opfile, "w")
sys.stdout = out
except IOError:
sys.stderr.write("Cannot open %s for writing\n" % opfile)
sys.exit(1)
def calculate():
global d
global v
global l2exist
v = dict()
v["time"] = time.strftime("%H:%M:%S", time.localtime())
v["hits"] = d["hits"] / sint
v["miss"] = d["misses"] / sint
v["read"] = v["hits"] + v["miss"]
v["hit%"] = 100 * v["hits"] / v["read"] if v["read"] > 0 else 0
v["miss%"] = 100 - v["hit%"] if v["read"] > 0 else 0
v["dhit"] = (d["demand_data_hits"] + d["demand_metadata_hits"]) / sint
v["dmis"] = (d["demand_data_misses"] + d["demand_metadata_misses"]) / sint
v["dread"] = v["dhit"] + v["dmis"]
v["dh%"] = 100 * v["dhit"] / v["dread"] if v["dread"] > 0 else 0
v["dm%"] = 100 - v["dh%"] if v["dread"] > 0 else 0
v["phit"] = (d["prefetch_data_hits"] + d["prefetch_metadata_hits"]) / sint
v["pmis"] = (d["prefetch_data_misses"] +
d["prefetch_metadata_misses"]) / sint
v["pread"] = v["phit"] + v["pmis"]
v["ph%"] = 100 * v["phit"] / v["pread"] if v["pread"] > 0 else 0
v["pm%"] = 100 - v["ph%"] if v["pread"] > 0 else 0
v["mhit"] = (d["prefetch_metadata_hits"] +
d["demand_metadata_hits"]) / sint
v["mmis"] = (d["prefetch_metadata_misses"] +
d["demand_metadata_misses"]) / sint
v["mread"] = v["mhit"] + v["mmis"]
v["mh%"] = 100 * v["mhit"] / v["mread"] if v["mread"] > 0 else 0
v["mm%"] = 100 - v["mh%"] if v["mread"] > 0 else 0
v["arcsz"] = cur["size"]
v["size"] = cur["size"]
v["c"] = cur["c"]
v["mfu"] = d["mfu_hits"] / sint
v["mru"] = d["mru_hits"] / sint
v["mrug"] = d["mru_ghost_hits"] / sint
v["mfug"] = d["mfu_ghost_hits"] / sint
v["eskip"] = d["evict_skip"] / sint
v["el2skip"] = d["evict_l2_skip"] / sint
v["el2cach"] = d["evict_l2_cached"] / sint
v["el2el"] = d["evict_l2_eligible"] / sint
v["el2mfu"] = d["evict_l2_eligible_mfu"] / sint
v["el2mru"] = d["evict_l2_eligible_mru"] / sint
v["el2inel"] = d["evict_l2_ineligible"] / sint
v["mtxmis"] = d["mutex_miss"] / sint
if l2exist:
v["l2hits"] = d["l2_hits"] / sint
v["l2miss"] = d["l2_misses"] / sint
v["l2read"] = v["l2hits"] + v["l2miss"]
v["l2hit%"] = 100 * v["l2hits"] / v["l2read"] if v["l2read"] > 0 else 0
v["l2miss%"] = 100 - v["l2hit%"] if v["l2read"] > 0 else 0
v["l2asize"] = cur["l2_asize"]
v["l2size"] = cur["l2_size"]
v["l2bytes"] = d["l2_read_bytes"] / sint
v["l2pref"] = cur["l2_prefetch_asize"]
v["l2mfu"] = cur["l2_mfu_asize"]
v["l2mru"] = cur["l2_mru_asize"]
v["l2data"] = cur["l2_bufc_data_asize"]
v["l2meta"] = cur["l2_bufc_metadata_asize"]
v["l2pref%"] = 100 * v["l2pref"] / v["l2asize"]
v["l2mfu%"] = 100 * v["l2mfu"] / v["l2asize"]
v["l2mru%"] = 100 * v["l2mru"] / v["l2asize"]
v["l2data%"] = 100 * v["l2data"] / v["l2asize"]
v["l2meta%"] = 100 * v["l2meta"] / v["l2asize"]
v["grow"] = 0 if cur["arc_no_grow"] else 1
v["need"] = cur["arc_need_free"]
v["free"] = cur["memory_free_bytes"]
v["avail"] = cur["memory_available_bytes"]
v["waste"] = cur["abd_chunk_waste_size"]
def main():
global sint
global count
global hdr_intr
i = 0
count_flag = 0
init()
if count > 0:
count_flag = 1
signal(SIGINT, SIG_DFL)
signal(SIGWINCH, resize_handler)
while True:
if i == 0:
print_header()
snap_stats()
calculate()
print_values()
if count_flag == 1:
if count <= 1:
break
count -= 1
i = 0 if i >= hdr_intr else i + 1
time.sleep(sint)
if out:
out.close()
if __name__ == '__main__':
main()
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