blob: df17a2ae80e5f900576dc0a55af0c2544db6365b [file] [log] [blame]
#!/usr/bin/env python3
# Copyright (C) 2019 Tejun Heo <>
# Copyright (C) 2019 Andy Newell <>
# Copyright (C) 2019 Facebook
desc = """
Generate linear IO cost model coefficients used by the blk-iocost
controller. If the target raw testdev is specified, destructive tests
are performed against the whole device; otherwise, on
./iocost-coef-fio.testfile. The result can be written directly to
On high performance devices, --numjobs > 1 is needed to achieve
See Documentation/admin-guide/cgroup-v2.rst and block/blk-iocost.c
for more details.
import argparse
import re
import json
import glob
import os
import sys
import atexit
import shutil
import tempfile
import subprocess
parser = argparse.ArgumentParser(description=desc,
parser.add_argument('--testdev', metavar='DEV',
help='Raw block device to use for testing, ignores --testfile-size')
parser.add_argument('--testfile-size-gb', type=float, metavar='GIGABYTES', default=16,
help='Testfile size in gigabytes (default: %(default)s)')
parser.add_argument('--duration', type=int, metavar='SECONDS', default=120,
help='Individual test run duration in seconds (default: %(default)s)')
parser.add_argument('--seqio-block-mb', metavar='MEGABYTES', type=int, default=128,
help='Sequential test block size in megabytes (default: %(default)s)')
parser.add_argument('--seq-depth', type=int, metavar='DEPTH', default=64,
help='Sequential test queue depth (default: %(default)s)')
parser.add_argument('--rand-depth', type=int, metavar='DEPTH', default=64,
help='Random test queue depth (default: %(default)s)')
parser.add_argument('--numjobs', type=int, metavar='JOBS', default=1,
help='Number of parallel fio jobs to run (default: %(default)s)')
parser.add_argument('--quiet', action='store_true')
parser.add_argument('--verbose', action='store_true')
def info(msg):
if not args.quiet:
def dbg(msg):
if args.verbose and not args.quiet:
# determine ('DEVNAME', 'MAJ:MIN') for @path
def dir_to_dev(path):
# find the block device the current directory is on
devname ='findmnt -nvo SOURCE -T{path}',
stdout=subprocess.PIPE, shell=True).stdout
devname = os.path.basename(devname).decode('utf-8').strip()
# partition -> whole device
parents = glob.glob('/sys/block/*/' + devname)
if len(parents):
devname = os.path.basename(os.path.dirname(parents[0]))
rdev = os.stat(f'/dev/{devname}').st_rdev
return (devname, f'{os.major(rdev)}:{os.minor(rdev)}')
def create_testfile(path, size):
global args
if os.path.isfile(path) and os.stat(path).st_size == size:
info(f'Creating testfile {path}')
subprocess.check_call(f'rm -f {path}', shell=True)
subprocess.check_call(f'touch {path}', shell=True)'chattr +C {path}', shell=True)
f'pv -s {size} -pr /dev/urandom {"-q" if args.quiet else ""} | '
f'dd of={path} count={size} '
f'iflag=count_bytes,fullblock oflag=direct bs=16M status=none',
def run_fio(testfile, duration, iotype, iodepth, blocksize, jobs):
global args
eta = 'never' if args.quiet else 'always'
outfile = tempfile.NamedTemporaryFile()
cmd = (f'fio --direct=1 --ioengine=libaio --name=coef '
f'--filename={testfile} --runtime={round(duration)} '
f'--readwrite={iotype} --iodepth={iodepth} --blocksize={blocksize} '
f'--eta={eta} --output-format json --output={} '
f'--time_based --numjobs={jobs}')
if args.verbose:
dbg(f'Running {cmd}')
subprocess.check_call(cmd, shell=True)
with open(, 'r') as f:
d = json.loads(
return sum(j['read']['bw_bytes'] + j['write']['bw_bytes'] for j in d['jobs'])
def restore_elevator_nomerges():
global elevator_path, nomerges_path, elevator, nomerges
info(f'Restoring elevator to {elevator} and nomerges to {nomerges}')
with open(elevator_path, 'w') as f:
with open(nomerges_path, 'w') as f:
args = parser.parse_args()
missing = False
for cmd in [ 'findmnt', 'pv', 'dd', 'fio' ]:
if not shutil.which(cmd):
print(f'Required command "{cmd}" is missing', file=sys.stderr)
missing = True
if missing:
if args.testdev:
devname = os.path.basename(args.testdev)
rdev = os.stat(f'/dev/{devname}').st_rdev
devno = f'{os.major(rdev)}:{os.minor(rdev)}'
testfile = f'/dev/{devname}'
info(f'Test target: {devname}({devno})')
devname, devno = dir_to_dev('.')
testfile = 'iocost-coef-fio.testfile'
testfile_size = int(args.testfile_size_gb * 2 ** 30)
create_testfile(testfile, testfile_size)
info(f'Test target: {testfile} on {devname}({devno})')
elevator_path = f'/sys/block/{devname}/queue/scheduler'
nomerges_path = f'/sys/block/{devname}/queue/nomerges'
with open(elevator_path, 'r') as f:
elevator = re.sub(r'.*\[(.*)\].*', r'\1',
with open(nomerges_path, 'r') as f:
nomerges =
info(f'Temporarily disabling elevator and merges')
with open(elevator_path, 'w') as f:
with open(nomerges_path, 'w') as f:
info('Determining rbps...')
rbps = run_fio(testfile, args.duration, 'read',
1, args.seqio_block_mb * (2 ** 20), args.numjobs)
info(f'\nrbps={rbps}, determining rseqiops...')
rseqiops = round(run_fio(testfile, args.duration, 'read',
args.seq_depth, 4096, args.numjobs) / 4096)
info(f'\nrseqiops={rseqiops}, determining rrandiops...')
rrandiops = round(run_fio(testfile, args.duration, 'randread',
args.rand_depth, 4096, args.numjobs) / 4096)
info(f'\nrrandiops={rrandiops}, determining wbps...')
wbps = run_fio(testfile, args.duration, 'write',
1, args.seqio_block_mb * (2 ** 20), args.numjobs)
info(f'\nwbps={wbps}, determining wseqiops...')
wseqiops = round(run_fio(testfile, args.duration, 'write',
args.seq_depth, 4096, args.numjobs) / 4096)
info(f'\nwseqiops={wseqiops}, determining wrandiops...')
wrandiops = round(run_fio(testfile, args.duration, 'randwrite',
args.rand_depth, 4096, args.numjobs) / 4096)
print(f'{devno} rbps={rbps} rseqiops={rseqiops} rrandiops={rrandiops} '
f'wbps={wbps} wseqiops={wseqiops} wrandiops={wrandiops}')