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>
This commit is contained in:
Kemeng Shi
Andrew Morton
parent
4b5bbc39d7
commit
881f1bb5e2
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#!/usr/bin/env drgn
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#
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# Copyright (C) 2024 Kemeng Shi <shikemeng@huaweicloud.com>
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# Copyright (C) 2024 Huawei Inc
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desc = """
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This is a drgn script based on wq_monitor.py to monitor writeback info on
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backing dev. For more info on drgn, visit https://github.com/osandov/drgn.
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writeback(kB) Amount of dirty pages are currently being written back to
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disk.
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reclaimable(kB) Amount of pages are currently reclaimable.
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dirtied(kB) Amount of pages have been dirtied.
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wrttien(kB) Amount of dirty pages have been written back to disk.
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avg_wb(kBps) Smoothly estimated write bandwidth of writing dirty pages
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back to disk.
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"""
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import signal
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import re
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import time
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import json
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import drgn
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from drgn.helpers.linux.list import list_for_each_entry
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import argparse
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parser = argparse.ArgumentParser(description=desc,
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formatter_class=argparse.RawTextHelpFormatter)
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parser.add_argument('bdi', metavar='REGEX', nargs='*',
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help='Target backing device name patterns (all if empty)')
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parser.add_argument('-i', '--interval', metavar='SECS', type=float, default=1,
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help='Monitoring interval (0 to print once and exit)')
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parser.add_argument('-j', '--json', action='store_true',
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help='Output in json')
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parser.add_argument('-c', '--cgroup', action='store_true',
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help='show writeback of bdi in cgroup')
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args = parser.parse_args()
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bdi_list = prog['bdi_list']
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WB_RECLAIMABLE = prog['WB_RECLAIMABLE']
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WB_WRITEBACK = prog['WB_WRITEBACK']
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WB_DIRTIED = prog['WB_DIRTIED']
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WB_WRITTEN = prog['WB_WRITTEN']
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NR_WB_STAT_ITEMS = prog['NR_WB_STAT_ITEMS']
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PAGE_SHIFT = prog['PAGE_SHIFT']
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def K(x):
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return x << (PAGE_SHIFT - 10)
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class Stats:
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def dict(self, now):
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return { 'timestamp' : now,
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'name' : self.name,
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'writeback' : self.stats[WB_WRITEBACK],
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'reclaimable' : self.stats[WB_RECLAIMABLE],
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'dirtied' : self.stats[WB_DIRTIED],
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'written' : self.stats[WB_WRITTEN],
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'avg_wb' : self.avg_bw, }
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def table_header_str():
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return f'{"":>16} {"writeback":>10} {"reclaimable":>12} ' \
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f'{"dirtied":>9} {"written":>9} {"avg_bw":>9}'
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def table_row_str(self):
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out = f'{self.name[-16:]:16} ' \
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f'{self.stats[WB_WRITEBACK]:10} ' \
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f'{self.stats[WB_RECLAIMABLE]:12} ' \
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f'{self.stats[WB_DIRTIED]:9} ' \
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f'{self.stats[WB_WRITTEN]:9} ' \
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f'{self.avg_bw:9} '
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return out
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def show_header():
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if Stats.table_fmt:
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print()
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print(Stats.table_header_str())
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def show_stats(self):
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if Stats.table_fmt:
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print(self.table_row_str())
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else:
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print(self.dict(Stats.now))
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class WbStats(Stats):
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def __init__(self, wb):
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bdi_name = wb.bdi.dev_name.string_().decode()
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# avoid to use bdi.wb.memcg_css which is only defined when
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# CONFIG_CGROUP_WRITEBACK is enabled
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if wb == wb.bdi.wb.address_of_():
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ino = "1"
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else:
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ino = str(wb.memcg_css.cgroup.kn.id.value_())
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self.name = bdi_name + '_' + ino
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self.stats = [0] * NR_WB_STAT_ITEMS
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for i in range(NR_WB_STAT_ITEMS):
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if wb.stat[i].count >= 0:
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self.stats[i] = int(K(wb.stat[i].count))
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else:
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self.stats[i] = 0
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self.avg_bw = int(K(wb.avg_write_bandwidth))
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class BdiStats(Stats):
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def __init__(self, bdi):
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self.name = bdi.dev_name.string_().decode()
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self.stats = [0] * NR_WB_STAT_ITEMS
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self.avg_bw = 0
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def collectStats(self, wb_stats):
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for i in range(NR_WB_STAT_ITEMS):
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self.stats[i] += wb_stats.stats[i]
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self.avg_bw += wb_stats.avg_bw
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exit_req = False
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def sigint_handler(signr, frame):
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global exit_req
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exit_req = True
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def main():
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# handle args
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Stats.table_fmt = not args.json
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interval = args.interval
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cgroup = args.cgroup
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re_str = None
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if args.bdi:
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for r in args.bdi:
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if re_str is None:
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re_str = r
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else:
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re_str += '|' + r
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filter_re = re.compile(re_str) if re_str else None
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# monitoring loop
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signal.signal(signal.SIGINT, sigint_handler)
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while not exit_req:
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Stats.now = time.time()
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Stats.show_header()
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for bdi in list_for_each_entry('struct backing_dev_info', bdi_list.address_of_(), 'bdi_list'):
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bdi_stats = BdiStats(bdi)
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if filter_re and not filter_re.search(bdi_stats.name):
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continue
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for wb in list_for_each_entry('struct bdi_writeback', bdi.wb_list.address_of_(), 'bdi_node'):
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wb_stats = WbStats(wb)
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bdi_stats.collectStats(wb_stats)
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if cgroup:
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wb_stats.show_stats()
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bdi_stats.show_stats()
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if cgroup and Stats.table_fmt:
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print()
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if interval == 0:
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break
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time.sleep(interval)
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if __name__ == "__main__":
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main()
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