1#!/usr/bin/env drgn
2#
3# Copyright (C) 2019 Tejun Heo <tj@kernel.org>
4# Copyright (C) 2019 Facebook
5
6desc = """
7This is a drgn script to monitor the blk-iocost cgroup controller.
8See the comment at the top of block/blk-iocost.c for more details.
9For drgn, visit https://github.com/osandov/drgn.
10"""
11
12import sys
13import re
14import time
15import json
16import math
17
18import drgn
19from drgn import container_of
20from drgn.helpers.linux.list import list_for_each_entry,list_empty
21from drgn.helpers.linux.radixtree import radix_tree_for_each,radix_tree_lookup
22
23import argparse
24parser = argparse.ArgumentParser(description=desc,
25                                 formatter_class=argparse.RawTextHelpFormatter)
26parser.add_argument('devname', metavar='DEV',
27                    help='Target block device name (e.g. sda)')
28parser.add_argument('--cgroup', action='append', metavar='REGEX',
29                    help='Regex for target cgroups, ')
30parser.add_argument('--interval', '-i', metavar='SECONDS', type=float, default=1,
31                    help='Monitoring interval in seconds')
32parser.add_argument('--json', action='store_true',
33                    help='Output in json')
34args = parser.parse_args()
35
36def err(s):
37    print(s, file=sys.stderr, flush=True)
38    sys.exit(1)
39
40try:
41    blkcg_root = prog['blkcg_root']
42    plid = prog['blkcg_policy_iocost'].plid.value_()
43except:
44    err('The kernel does not have iocost enabled')
45
46IOC_RUNNING     = prog['IOC_RUNNING'].value_()
47NR_USAGE_SLOTS  = prog['NR_USAGE_SLOTS'].value_()
48HWEIGHT_WHOLE   = prog['HWEIGHT_WHOLE'].value_()
49VTIME_PER_SEC   = prog['VTIME_PER_SEC'].value_()
50VTIME_PER_USEC  = prog['VTIME_PER_USEC'].value_()
51AUTOP_SSD_FAST  = prog['AUTOP_SSD_FAST'].value_()
52AUTOP_SSD_DFL   = prog['AUTOP_SSD_DFL'].value_()
53AUTOP_SSD_QD1   = prog['AUTOP_SSD_QD1'].value_()
54AUTOP_HDD       = prog['AUTOP_HDD'].value_()
55
56autop_names = {
57    AUTOP_SSD_FAST:        'ssd_fast',
58    AUTOP_SSD_DFL:         'ssd_dfl',
59    AUTOP_SSD_QD1:         'ssd_qd1',
60    AUTOP_HDD:             'hdd',
61}
62
63class BlkgIterator:
64    def blkcg_name(blkcg):
65        return blkcg.css.cgroup.kn.name.string_().decode('utf-8')
66
67    def walk(self, blkcg, q_id, parent_path):
68        if not self.include_dying and \
69           not (blkcg.css.flags.value_() & prog['CSS_ONLINE'].value_()):
70            return
71
72        name = BlkgIterator.blkcg_name(blkcg)
73        path = parent_path + '/' + name if parent_path else name
74        blkg = drgn.Object(prog, 'struct blkcg_gq',
75                           address=radix_tree_lookup(blkcg.blkg_tree, q_id))
76        if not blkg.address_:
77            return
78
79        self.blkgs.append((path if path else '/', blkg))
80
81        for c in list_for_each_entry('struct blkcg',
82                                     blkcg.css.children.address_of_(), 'css.sibling'):
83            self.walk(c, q_id, path)
84
85    def __init__(self, root_blkcg, q_id, include_dying=False):
86        self.include_dying = include_dying
87        self.blkgs = []
88        self.walk(root_blkcg, q_id, '')
89
90    def __iter__(self):
91        return iter(self.blkgs)
92
93class IocStat:
94    def __init__(self, ioc):
95        global autop_names
96
97        self.enabled = ioc.enabled.value_()
98        self.running = ioc.running.value_() == IOC_RUNNING
99        self.period_ms = ioc.period_us.value_() / 1_000
100        self.period_at = ioc.period_at.value_() / 1_000_000
101        self.vperiod_at = ioc.period_at_vtime.value_() / VTIME_PER_SEC
102        self.vrate_pct = ioc.vtime_rate.counter.value_() * 100 / VTIME_PER_USEC
103        self.busy_level = ioc.busy_level.value_()
104        self.autop_idx = ioc.autop_idx.value_()
105        self.user_cost_model = ioc.user_cost_model.value_()
106        self.user_qos_params = ioc.user_qos_params.value_()
107
108        if self.autop_idx in autop_names:
109            self.autop_name = autop_names[self.autop_idx]
110        else:
111            self.autop_name = '?'
112
113    def dict(self, now):
114        return { 'device'               : devname,
115                 'timestamp'            : str(now),
116                 'enabled'              : str(int(self.enabled)),
117                 'running'              : str(int(self.running)),
118                 'period_ms'            : str(self.period_ms),
119                 'period_at'            : str(self.period_at),
120                 'period_vtime_at'      : str(self.vperiod_at),
121                 'busy_level'           : str(self.busy_level),
122                 'vrate_pct'            : str(self.vrate_pct), }
123
124    def table_preamble_str(self):
125        state = ('RUN' if self.running else 'IDLE') if self.enabled else 'OFF'
126        output = f'{devname} {state:4} ' \
127                 f'per={self.period_ms}ms ' \
128                 f'cur_per={self.period_at:.3f}:v{self.vperiod_at:.3f} ' \
129                 f'busy={self.busy_level:+3} ' \
130                 f'vrate={self.vrate_pct:6.2f}% ' \
131                 f'params={self.autop_name}'
132        if self.user_cost_model or self.user_qos_params:
133            output += f'({"C" if self.user_cost_model else ""}{"Q" if self.user_qos_params else ""})'
134        return output
135
136    def table_header_str(self):
137        return f'{"":25} active {"weight":>9} {"hweight%":>13} {"inflt%":>6} ' \
138               f'{"dbt":>3} {"delay":>6} {"usages%"}'
139
140class IocgStat:
141    def __init__(self, iocg):
142        ioc = iocg.ioc
143        blkg = iocg.pd.blkg
144
145        self.is_active = not list_empty(iocg.active_list.address_of_())
146        self.weight = iocg.weight.value_()
147        self.active = iocg.active.value_()
148        self.inuse = iocg.inuse.value_()
149        self.hwa_pct = iocg.hweight_active.value_() * 100 / HWEIGHT_WHOLE
150        self.hwi_pct = iocg.hweight_inuse.value_() * 100 / HWEIGHT_WHOLE
151        self.address = iocg.value_()
152
153        vdone = iocg.done_vtime.counter.value_()
154        vtime = iocg.vtime.counter.value_()
155        vrate = ioc.vtime_rate.counter.value_()
156        period_vtime = ioc.period_us.value_() * vrate
157        if period_vtime:
158            self.inflight_pct = (vtime - vdone) * 100 / period_vtime
159        else:
160            self.inflight_pct = 0
161
162        self.debt_ms = iocg.abs_vdebt.counter.value_() / VTIME_PER_USEC / 1000
163        self.use_delay = blkg.use_delay.counter.value_()
164        self.delay_ms = blkg.delay_nsec.counter.value_() / 1_000_000
165
166        usage_idx = iocg.usage_idx.value_()
167        self.usages = []
168        self.usage = 0
169        for i in range(NR_USAGE_SLOTS):
170            usage = iocg.usages[(usage_idx + i) % NR_USAGE_SLOTS].value_()
171            upct = usage * 100 / HWEIGHT_WHOLE
172            self.usages.append(upct)
173            self.usage = max(self.usage, upct)
174
175    def dict(self, now, path):
176        out = { 'cgroup'                : path,
177                'timestamp'             : str(now),
178                'is_active'             : str(int(self.is_active)),
179                'weight'                : str(self.weight),
180                'weight_active'         : str(self.active),
181                'weight_inuse'          : str(self.inuse),
182                'hweight_active_pct'    : str(self.hwa_pct),
183                'hweight_inuse_pct'     : str(self.hwi_pct),
184                'inflight_pct'          : str(self.inflight_pct),
185                'debt_ms'               : str(self.debt_ms),
186                'use_delay'             : str(self.use_delay),
187                'delay_ms'              : str(self.delay_ms),
188                'usage_pct'             : str(self.usage),
189                'address'               : str(hex(self.address)) }
190        for i in range(len(self.usages)):
191            out[f'usage_pct_{i}'] = str(self.usages[i])
192        return out
193
194    def table_row_str(self, path):
195        out = f'{path[-28:]:28} ' \
196              f'{"*" if self.is_active else " "} ' \
197              f'{self.inuse:5}/{self.active:5} ' \
198              f'{self.hwi_pct:6.2f}/{self.hwa_pct:6.2f} ' \
199              f'{self.inflight_pct:6.2f} ' \
200              f'{min(math.ceil(self.debt_ms), 999):3} ' \
201              f'{min(self.use_delay, 99):2}*'\
202              f'{min(math.ceil(self.delay_ms), 999):03} '
203        for u in self.usages:
204            out += f'{min(round(u), 999):03d}:'
205        out = out.rstrip(':')
206        return out
207
208# handle args
209table_fmt = not args.json
210interval = args.interval
211devname = args.devname
212
213if args.json:
214    table_fmt = False
215
216re_str = None
217if args.cgroup:
218    for r in args.cgroup:
219        if re_str is None:
220            re_str = r
221        else:
222            re_str += '|' + r
223
224filter_re = re.compile(re_str) if re_str else None
225
226# Locate the roots
227q_id = None
228root_iocg = None
229ioc = None
230
231for i, ptr in radix_tree_for_each(blkcg_root.blkg_tree):
232    blkg = drgn.Object(prog, 'struct blkcg_gq', address=ptr)
233    try:
234        if devname == blkg.q.kobj.parent.name.string_().decode('utf-8'):
235            q_id = blkg.q.id.value_()
236            if blkg.pd[plid]:
237                root_iocg = container_of(blkg.pd[plid], 'struct ioc_gq', 'pd')
238                ioc = root_iocg.ioc
239            break
240    except:
241        pass
242
243if ioc is None:
244    err(f'Could not find ioc for {devname}');
245
246# Keep printing
247while True:
248    now = time.time()
249    iocstat = IocStat(ioc)
250    output = ''
251
252    if table_fmt:
253        output += '\n' + iocstat.table_preamble_str()
254        output += '\n' + iocstat.table_header_str()
255    else:
256        output += json.dumps(iocstat.dict(now))
257
258    for path, blkg in BlkgIterator(blkcg_root, q_id):
259        if filter_re and not filter_re.match(path):
260            continue
261        if not blkg.pd[plid]:
262            continue
263
264        iocg = container_of(blkg.pd[plid], 'struct ioc_gq', 'pd')
265        iocg_stat = IocgStat(iocg)
266
267        if not filter_re and not iocg_stat.is_active:
268            continue
269
270        if table_fmt:
271            output += '\n' + iocg_stat.table_row_str(path)
272        else:
273            output += '\n' + json.dumps(iocg_stat.dict(now, path))
274
275    print(output)
276    sys.stdout.flush()
277    time.sleep(interval)
278