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 (0 exits immediately '
32                    'after checking requirements)')
33parser.add_argument('--json', action='store_true',
34                    help='Output in json')
35args = parser.parse_args()
36
37def err(s):
38    print(s, file=sys.stderr, flush=True)
39    sys.exit(1)
40
41try:
42    blkcg_root = prog['blkcg_root']
43    plid = prog['blkcg_policy_iocost'].plid.value_()
44except:
45    err('The kernel does not have iocost enabled')
46
47IOC_RUNNING     = prog['IOC_RUNNING'].value_()
48WEIGHT_ONE      = prog['WEIGHT_ONE'].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 __init__(self, root_blkcg, q_id, include_dying=False):
65        self.include_dying = include_dying
66        self.blkgs = []
67        self.walk(root_blkcg, q_id, '')
68
69    def blkcg_name(blkcg):
70        return blkcg.css.cgroup.kn.name.string_().decode('utf-8')
71
72    def walk(self, blkcg, q_id, parent_path):
73        if not self.include_dying and \
74           not (blkcg.css.flags.value_() & prog['CSS_ONLINE'].value_()):
75            return
76
77        name = BlkgIterator.blkcg_name(blkcg)
78        path = parent_path + '/' + name if parent_path else name
79        blkg = drgn.Object(prog, 'struct blkcg_gq',
80                           address=radix_tree_lookup(blkcg.blkg_tree.address_of_(), q_id))
81        if not blkg.address_:
82            return
83
84        self.blkgs.append((path if path else '/', blkg))
85
86        for c in list_for_each_entry('struct blkcg',
87                                     blkcg.css.children.address_of_(), 'css.sibling'):
88            self.walk(c, q_id, path)
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_base_rate.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'            : now,
116                 'enabled'              : self.enabled,
117                 'running'              : self.running,
118                 'period_ms'            : self.period_ms,
119                 'period_at'            : self.period_at,
120                 'period_vtime_at'      : self.vperiod_at,
121                 'busy_level'           : self.busy_level,
122                 'vrate_pct'            : 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'{"debt":>7} {"delay":>7} {"usage%"}'
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_() / WEIGHT_ONE
147        self.active = iocg.active.value_() / WEIGHT_ONE
148        self.inuse = iocg.inuse.value_() / WEIGHT_ONE
149        self.hwa_pct = iocg.hweight_active.value_() * 100 / WEIGHT_ONE
150        self.hwi_pct = iocg.hweight_inuse.value_() * 100 / WEIGHT_ONE
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.usage = (100 * iocg.usage_delta_us.value_() /
163                      ioc.period_us.value_()) if self.active else 0
164        self.debt_ms = iocg.abs_vdebt.value_() / VTIME_PER_USEC / 1000
165        if blkg.use_delay.counter.value_() != 0:
166            self.delay_ms = blkg.delay_nsec.counter.value_() / 1_000_000
167        else:
168            self.delay_ms = 0
169
170    def dict(self, now, path):
171        out = { 'cgroup'                : path,
172                'timestamp'             : now,
173                'is_active'             : self.is_active,
174                'weight'                : self.weight,
175                'weight_active'         : self.active,
176                'weight_inuse'          : self.inuse,
177                'hweight_active_pct'    : self.hwa_pct,
178                'hweight_inuse_pct'     : self.hwi_pct,
179                'inflight_pct'          : self.inflight_pct,
180                'debt_ms'               : self.debt_ms,
181                'delay_ms'              : self.delay_ms,
182                'usage_pct'             : self.usage,
183                'address'               : self.address }
184        return out
185
186    def table_row_str(self, path):
187        out = f'{path[-28:]:28} ' \
188              f'{"*" if self.is_active else " "} ' \
189              f'{round(self.inuse):5}/{round(self.active):5} ' \
190              f'{self.hwi_pct:6.2f}/{self.hwa_pct:6.2f} ' \
191              f'{self.inflight_pct:6.2f} ' \
192              f'{self.debt_ms:7.2f} ' \
193              f'{self.delay_ms:7.2f} '\
194              f'{min(self.usage, 999):6.2f}'
195        out = out.rstrip(':')
196        return out
197
198# handle args
199table_fmt = not args.json
200interval = args.interval
201devname = args.devname
202
203if args.json:
204    table_fmt = False
205
206re_str = None
207if args.cgroup:
208    for r in args.cgroup:
209        if re_str is None:
210            re_str = r
211        else:
212            re_str += '|' + r
213
214filter_re = re.compile(re_str) if re_str else None
215
216# Locate the roots
217q_id = None
218root_iocg = None
219ioc = None
220
221for i, ptr in radix_tree_for_each(blkcg_root.blkg_tree.address_of_()):
222    blkg = drgn.Object(prog, 'struct blkcg_gq', address=ptr)
223    try:
224        if devname == blkg.q.kobj.parent.name.string_().decode('utf-8'):
225            q_id = blkg.q.id.value_()
226            if blkg.pd[plid]:
227                root_iocg = container_of(blkg.pd[plid], 'struct ioc_gq', 'pd')
228                ioc = root_iocg.ioc
229            break
230    except:
231        pass
232
233if ioc is None:
234    err(f'Could not find ioc for {devname}');
235
236if interval == 0:
237    sys.exit(0)
238
239# Keep printing
240while True:
241    now = time.time()
242    iocstat = IocStat(ioc)
243    output = ''
244
245    if table_fmt:
246        output += '\n' + iocstat.table_preamble_str()
247        output += '\n' + iocstat.table_header_str()
248    else:
249        output += json.dumps(iocstat.dict(now))
250
251    for path, blkg in BlkgIterator(blkcg_root, q_id):
252        if filter_re and not filter_re.match(path):
253            continue
254        if not blkg.pd[plid]:
255            continue
256
257        iocg = container_of(blkg.pd[plid], 'struct ioc_gq', 'pd')
258        iocg_stat = IocgStat(iocg)
259
260        if not filter_re and not iocg_stat.is_active:
261            continue
262
263        if table_fmt:
264            output += '\n' + iocg_stat.table_row_str(path)
265        else:
266            output += '\n' + json.dumps(iocg_stat.dict(now, path))
267
268    print(output)
269    sys.stdout.flush()
270    time.sleep(interval)
271