linux/tools/writeback/wb_monitor.py
Kemeng Shi 881f1bb5e2 writeback: add wb_monitor.py script to monitor writeback info on bdi
Add wb_monitor.py script to monitor writeback information on backing dev
which makes it easier and more convenient to observe writeback behaviors
of running system.

The wb_monitor.py script is written based on wq_monitor.py.

Following domain hierarchy is tested:
                global domain (320G)
                /                 \
        cgroup domain1(10G)     cgroup domain2(10G)
                |                 |
bdi            wb1               wb2

The wb_monitor.py script output is as following:
./wb_monitor.py 252:16 -c
                  writeback  reclaimable   dirtied   written    avg_bw
252:16_1                  0            0         0         0    102400
252:16_4284             672       820064   9230368   8410304    685612
252:16_4325             896       819840  10491264   9671648    652348
252:16                 1568      1639904  19721632  18081952   1440360

                  writeback  reclaimable   dirtied   written    avg_bw
252:16_1                  0            0         0         0    102400
252:16_4284             672       820064   9230368   8410304    685612
252:16_4325             896       819840  10491264   9671648    652348
252:16                 1568      1639904  19721632  18081952   1440360
...

Link: https://lkml.kernel.org/r/20240423034643.141219-5-shikemeng@huaweicloud.com
Signed-off-by: Kemeng Shi <shikemeng@huaweicloud.com>
Suggested-by: Tejun Heo <tj@kernel.org>
Cc: Brian Foster <bfoster@redhat.com>
Cc: David Howells <dhowells@redhat.com>
Cc: David Sterba <dsterba@suse.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Mateusz Guzik <mjguzik@gmail.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: SeongJae Park <sj@kernel.org>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-05-05 17:53:51 -07:00

173 lines
5.3 KiB
Python

#!/usr/bin/env drgn
#
# Copyright (C) 2024 Kemeng Shi <shikemeng@huaweicloud.com>
# Copyright (C) 2024 Huawei Inc
desc = """
This is a drgn script based on wq_monitor.py to monitor writeback info on
backing dev. For more info on drgn, visit https://github.com/osandov/drgn.
writeback(kB) Amount of dirty pages are currently being written back to
disk.
reclaimable(kB) Amount of pages are currently reclaimable.
dirtied(kB) Amount of pages have been dirtied.
wrttien(kB) Amount of dirty pages have been written back to disk.
avg_wb(kBps) Smoothly estimated write bandwidth of writing dirty pages
back to disk.
"""
import signal
import re
import time
import json
import drgn
from drgn.helpers.linux.list import list_for_each_entry
import argparse
parser = argparse.ArgumentParser(description=desc,
formatter_class=argparse.RawTextHelpFormatter)
parser.add_argument('bdi', metavar='REGEX', nargs='*',
help='Target backing device name patterns (all if empty)')
parser.add_argument('-i', '--interval', metavar='SECS', type=float, default=1,
help='Monitoring interval (0 to print once and exit)')
parser.add_argument('-j', '--json', action='store_true',
help='Output in json')
parser.add_argument('-c', '--cgroup', action='store_true',
help='show writeback of bdi in cgroup')
args = parser.parse_args()
bdi_list = prog['bdi_list']
WB_RECLAIMABLE = prog['WB_RECLAIMABLE']
WB_WRITEBACK = prog['WB_WRITEBACK']
WB_DIRTIED = prog['WB_DIRTIED']
WB_WRITTEN = prog['WB_WRITTEN']
NR_WB_STAT_ITEMS = prog['NR_WB_STAT_ITEMS']
PAGE_SHIFT = prog['PAGE_SHIFT']
def K(x):
return x << (PAGE_SHIFT - 10)
class Stats:
def dict(self, now):
return { 'timestamp' : now,
'name' : self.name,
'writeback' : self.stats[WB_WRITEBACK],
'reclaimable' : self.stats[WB_RECLAIMABLE],
'dirtied' : self.stats[WB_DIRTIED],
'written' : self.stats[WB_WRITTEN],
'avg_wb' : self.avg_bw, }
def table_header_str():
return f'{"":>16} {"writeback":>10} {"reclaimable":>12} ' \
f'{"dirtied":>9} {"written":>9} {"avg_bw":>9}'
def table_row_str(self):
out = f'{self.name[-16:]:16} ' \
f'{self.stats[WB_WRITEBACK]:10} ' \
f'{self.stats[WB_RECLAIMABLE]:12} ' \
f'{self.stats[WB_DIRTIED]:9} ' \
f'{self.stats[WB_WRITTEN]:9} ' \
f'{self.avg_bw:9} '
return out
def show_header():
if Stats.table_fmt:
print()
print(Stats.table_header_str())
def show_stats(self):
if Stats.table_fmt:
print(self.table_row_str())
else:
print(self.dict(Stats.now))
class WbStats(Stats):
def __init__(self, wb):
bdi_name = wb.bdi.dev_name.string_().decode()
# avoid to use bdi.wb.memcg_css which is only defined when
# CONFIG_CGROUP_WRITEBACK is enabled
if wb == wb.bdi.wb.address_of_():
ino = "1"
else:
ino = str(wb.memcg_css.cgroup.kn.id.value_())
self.name = bdi_name + '_' + ino
self.stats = [0] * NR_WB_STAT_ITEMS
for i in range(NR_WB_STAT_ITEMS):
if wb.stat[i].count >= 0:
self.stats[i] = int(K(wb.stat[i].count))
else:
self.stats[i] = 0
self.avg_bw = int(K(wb.avg_write_bandwidth))
class BdiStats(Stats):
def __init__(self, bdi):
self.name = bdi.dev_name.string_().decode()
self.stats = [0] * NR_WB_STAT_ITEMS
self.avg_bw = 0
def collectStats(self, wb_stats):
for i in range(NR_WB_STAT_ITEMS):
self.stats[i] += wb_stats.stats[i]
self.avg_bw += wb_stats.avg_bw
exit_req = False
def sigint_handler(signr, frame):
global exit_req
exit_req = True
def main():
# handle args
Stats.table_fmt = not args.json
interval = args.interval
cgroup = args.cgroup
re_str = None
if args.bdi:
for r in args.bdi:
if re_str is None:
re_str = r
else:
re_str += '|' + r
filter_re = re.compile(re_str) if re_str else None
# monitoring loop
signal.signal(signal.SIGINT, sigint_handler)
while not exit_req:
Stats.now = time.time()
Stats.show_header()
for bdi in list_for_each_entry('struct backing_dev_info', bdi_list.address_of_(), 'bdi_list'):
bdi_stats = BdiStats(bdi)
if filter_re and not filter_re.search(bdi_stats.name):
continue
for wb in list_for_each_entry('struct bdi_writeback', bdi.wb_list.address_of_(), 'bdi_node'):
wb_stats = WbStats(wb)
bdi_stats.collectStats(wb_stats)
if cgroup:
wb_stats.show_stats()
bdi_stats.show_stats()
if cgroup and Stats.table_fmt:
print()
if interval == 0:
break
time.sleep(interval)
if __name__ == "__main__":
main()