tools/writeback/wb_monitor.py

   1 #!/usr/bin/env drgn
   2 #
   3 # Copyright (C) 2024 Kemeng Shi <[email protected]>
   4 # Copyright (C) 2024 Huawei Inc
   5
   6 desc = """
   7 This is a drgn script based on wq_monitor.py to monitor writeback info on
   8 backing dev. For more info on drgn, visit https://github.com/osandov/drgn.
   9
  10   writeback(kB)     Amount of dirty pages are currently being written back to
  11                     disk.
  12
  13   reclaimable(kB)   Amount of pages are currently reclaimable.
  14
  15   dirtied(kB)       Amount of pages have been dirtied.
  16
  17   wrttien(kB)       Amount of dirty pages have been written back to disk.
  18
  19   avg_wb(kBps)      Smoothly estimated write bandwidth of writing dirty pages
  20                     back to disk.
  21 """
  22
  23 import signal
  24 import re
  25 import time
  26 import json
  27
  28 import drgn
  29 from drgn.helpers.linux.list import list_for_each_entry
  30
  31 import argparse
  32 parser = argparse.ArgumentParser(description=desc,
  33                                  formatter_class=argparse.RawTextHelpFormatter)
  34 parser.add_argument('bdi', metavar='REGEX', nargs='*',
  35                     help='Target backing device name patterns (all if empty)')
  36 parser.add_argument('-i', '--interval', metavar='SECS', type=float, default=1,
  37                     help='Monitoring interval (0 to print once and exit)')
  38 parser.add_argument('-j', '--json', action='store_true',
  39                     help='Output in json')
  40 parser.add_argument('-c', '--cgroup', action='store_true',
  41                     help='show writeback of bdi in cgroup')
  42 args = parser.parse_args()
  43
  44 bdi_list                = prog['bdi_list']
  45
  46 WB_RECLAIMABLE          = prog['WB_RECLAIMABLE']
  47 WB_WRITEBACK            = prog['WB_WRITEBACK']
  48 WB_DIRTIED              = prog['WB_DIRTIED']
  49 WB_WRITTEN              = prog['WB_WRITTEN']
  50 NR_WB_STAT_ITEMS        = prog['NR_WB_STAT_ITEMS']
  51
  52 PAGE_SHIFT              = prog['PAGE_SHIFT']
  53
  54 def K(x):
  55     return x << (PAGE_SHIFT - 10)
  56
  57 class Stats:
  58     def dict(self, now):
  59         return { 'timestamp'            : now,
  60                  'name'                 : self.name,
  61                  'writeback'            : self.stats[WB_WRITEBACK],
  62                  'reclaimable'          : self.stats[WB_RECLAIMABLE],
  63                  'dirtied'              : self.stats[WB_DIRTIED],
  64                  'written'              : self.stats[WB_WRITTEN],
  65                  'avg_wb'               : self.avg_bw, }
  66
  67     def table_header_str():
  68         return f'{"":>16} {"writeback":>10} {"reclaimable":>12} ' \
  69                 f'{"dirtied":>9} {"written":>9} {"avg_bw":>9}'
  70
  71     def table_row_str(self):
  72         out = f'{self.name[-16:]:16} ' \
  73               f'{self.stats[WB_WRITEBACK]:10} ' \
  74               f'{self.stats[WB_RECLAIMABLE]:12} ' \
  75               f'{self.stats[WB_DIRTIED]:9} ' \
  76               f'{self.stats[WB_WRITTEN]:9} ' \
  77               f'{self.avg_bw:9} '
  78         return out
  79
  80     def show_header():
  81         if Stats.table_fmt:
  82             print()
  83             print(Stats.table_header_str())
  84
  85     def show_stats(self):
  86         if Stats.table_fmt:
  87             print(self.table_row_str())
  88         else:
  89             print(self.dict(Stats.now))
  90
  91 class WbStats(Stats):
  92     def __init__(self, wb):
  93         bdi_name = wb.bdi.dev_name.string_().decode()
  94         # avoid to use bdi.wb.memcg_css which is only defined when
  95         # CONFIG_CGROUP_WRITEBACK is enabled
  96         if wb == wb.bdi.wb.address_of_():
  97             ino = "1"
  98         else:
  99             ino = str(wb.memcg_css.cgroup.kn.id.value_())
 100         self.name = bdi_name + '_' + ino
 101
 102         self.stats = [0] * NR_WB_STAT_ITEMS
 103         for i in range(NR_WB_STAT_ITEMS):
 104             if wb.stat[i].count >= 0:
 105                 self.stats[i] = int(K(wb.stat[i].count))
 106             else:
 107                 self.stats[i] = 0
 108
 109         self.avg_bw = int(K(wb.avg_write_bandwidth))
 110
 111 class BdiStats(Stats):
 112     def __init__(self, bdi):
 113         self.name = bdi.dev_name.string_().decode()
 114         self.stats = [0] * NR_WB_STAT_ITEMS
 115         self.avg_bw = 0
 116
 117     def collectStats(self, wb_stats):
 118         for i in range(NR_WB_STAT_ITEMS):
 119             self.stats[i] += wb_stats.stats[i]
 120
 121         self.avg_bw += wb_stats.avg_bw
 122
 123 exit_req = False
 124
 125 def sigint_handler(signr, frame):
 126     global exit_req
 127     exit_req = True
 128
 129 def main():
 130     # handle args
 131     Stats.table_fmt = not args.json
 132     interval = args.interval
 133     cgroup = args.cgroup
 134
 135     re_str = None
 136     if args.bdi:
 137         for r in args.bdi:
 138             if re_str is None:
 139                 re_str = r
 140             else:
 141                 re_str += '|' + r
 142
 143     filter_re = re.compile(re_str) if re_str else None
 144
 145     # monitoring loop
 146     signal.signal(signal.SIGINT, sigint_handler)
 147
 148     while not exit_req:
 149         Stats.now = time.time()
 150
 151         Stats.show_header()
 152         for bdi in list_for_each_entry('struct backing_dev_info', bdi_list.address_of_(), 'bdi_list'):
 153             bdi_stats = BdiStats(bdi)
 154             if filter_re and not filter_re.search(bdi_stats.name):
 155                 continue
 156
 157             for wb in list_for_each_entry('struct bdi_writeback', bdi.wb_list.address_of_(), 'bdi_node'):
 158                 wb_stats = WbStats(wb)
 159                 bdi_stats.collectStats(wb_stats)
 160                 if cgroup:
 161                     wb_stats.show_stats()
 162
 163             bdi_stats.show_stats()
 164             if cgroup and Stats.table_fmt:
 165                 print()
 166
 167         if interval == 0:
 168             break
 169         time.sleep(interval)
 170
 171 if __name__ == "__main__":
 172     main()