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_()
48NR_USAGE_SLOTS  = prog['NR_USAGE_SLOTS'].value_()
49HWEIGHT_WHOLE   = prog['HWEIGHT_WHOLE'].value_()
50VTIME_PER_SEC   = prog['VTIME_PER_SEC'].value_()
51VTIME_PER_USEC  = prog['VTIME_PER_USEC'].value_()
52AUTOP_SSD_FAST  = prog['AUTOP_SSD_FAST'].value_()
53AUTOP_SSD_DFL   = prog['AUTOP_SSD_DFL'].value_()
54AUTOP_SSD_QD1   = prog['AUTOP_SSD_QD1'].value_()
55AUTOP_HDD       = prog['AUTOP_HDD'].value_()
56
57autop_names = {
58    AUTOP_SSD_FAST:        'ssd_fast',
59    AUTOP_SSD_DFL:         'ssd_dfl',
60    AUTOP_SSD_QD1:         'ssd_qd1',
61    AUTOP_HDD:             'hdd',
62}
63
64class BlkgIterator:
65    def blkcg_name(blkcg):
66        return blkcg.css.cgroup.kn.name.string_().decode('utf-8')
67
68    def walk(self, blkcg, q_id, parent_path):
69        if not self.include_dying and \
70           not (blkcg.css.flags.value_() & prog['CSS_ONLINE'].value_()):
71            return
72
73        name = BlkgIterator.blkcg_name(blkcg)
74        path = parent_path + '/' + name if parent_path else name
75        blkg = drgn.Object(prog, 'struct blkcg_gq',
76                           address=radix_tree_lookup(blkcg.blkg_tree.address_of_(), q_id))
77        if not blkg.address_:
78            return
79
80        self.blkgs.append((path if path else '/', blkg))
81
82        for c in list_for_each_entry('struct blkcg',
83                                     blkcg.css.children.address_of_(), 'css.sibling'):
84            self.walk(c, q_id, path)
85
86    def __init__(self, root_blkcg, q_id, include_dying=False):
87        self.include_dying = include_dying
88        self.blkgs = []
89        self.walk(root_blkcg, q_id, '')
90
91    def __iter__(self):
92        return iter(self.blkgs)
93
94class IocStat:
95    def __init__(self, ioc):
96        global autop_names
97
98        self.enabled = ioc.enabled.value_()
99        self.running = ioc.running.value_() == IOC_RUNNING
100        self.period_ms = ioc.period_us.value_() / 1_000
101        self.period_at = ioc.period_at.value_() / 1_000_000
102        self.vperiod_at = ioc.period_at_vtime.value_() / VTIME_PER_SEC
103        self.vrate_pct = ioc.vtime_rate.counter.value_() * 100 / VTIME_PER_USEC
104        self.busy_level = ioc.busy_level.value_()
105        self.autop_idx = ioc.autop_idx.value_()
106        self.user_cost_model = ioc.user_cost_model.value_()
107        self.user_qos_params = ioc.user_qos_params.value_()
108
109        if self.autop_idx in autop_names:
110            self.autop_name = autop_names[self.autop_idx]
111        else:
112            self.autop_name = '?'
113
114    def dict(self, now):
115        return { 'device'               : devname,
116                 'timestamp'            : now,
117                 'enabled'              : self.enabled,
118                 'running'              : self.running,
119                 'period_ms'            : self.period_ms,
120                 'period_at'            : self.period_at,
121                 'period_vtime_at'      : self.vperiod_at,
122                 'busy_level'           : self.busy_level,
123                 'vrate_pct'            : self.vrate_pct, }
124
125    def table_preamble_str(self):
126        state = ('RUN' if self.running else 'IDLE') if self.enabled else 'OFF'
127        output = f'{devname} {state:4} ' \
128                 f'per={self.period_ms}ms ' \
129                 f'cur_per={self.period_at:.3f}:v{self.vperiod_at:.3f} ' \
130                 f'busy={self.busy_level:+3} ' \
131                 f'vrate={self.vrate_pct:6.2f}% ' \
132                 f'params={self.autop_name}'
133        if self.user_cost_model or self.user_qos_params:
134            output += f'({"C" if self.user_cost_model else ""}{"Q" if self.user_qos_params else ""})'
135        return output
136
137    def table_header_str(self):
138        return f'{"":25} active {"weight":>9} {"hweight%":>13} {"inflt%":>6} ' \
139               f'{"dbt":>3} {"delay":>6} {"usages%"}'
140
141class IocgStat:
142    def __init__(self, iocg):
143        ioc = iocg.ioc
144        blkg = iocg.pd.blkg
145
146        self.is_active = not list_empty(iocg.active_list.address_of_())
147        self.weight = iocg.weight.value_()
148        self.active = iocg.active.value_()
149        self.inuse = iocg.inuse.value_()
150        self.hwa_pct = iocg.hweight_active.value_() * 100 / HWEIGHT_WHOLE
151        self.hwi_pct = iocg.hweight_inuse.value_() * 100 / HWEIGHT_WHOLE
152        self.address = iocg.value_()
153
154        vdone = iocg.done_vtime.counter.value_()
155        vtime = iocg.vtime.counter.value_()
156        vrate = ioc.vtime_rate.counter.value_()
157        period_vtime = ioc.period_us.value_() * vrate
158        if period_vtime:
159            self.inflight_pct = (vtime - vdone) * 100 / period_vtime
160        else:
161            self.inflight_pct = 0
162
163        # vdebt used to be an atomic64_t and is now u64, support both
164        try:
165            self.debt_ms = iocg.abs_vdebt.counter.value_() / VTIME_PER_USEC / 1000
166        except:
167            self.debt_ms = iocg.abs_vdebt.value_() / VTIME_PER_USEC / 1000
168
169        self.use_delay = blkg.use_delay.counter.value_()
170        self.delay_ms = blkg.delay_nsec.counter.value_() / 1_000_000
171
172        usage_idx = iocg.usage_idx.value_()
173        self.usages = []
174        self.usage = 0
175        for i in range(NR_USAGE_SLOTS):
176            usage = iocg.usages[(usage_idx + 1 + i) % NR_USAGE_SLOTS].value_()
177            upct = usage * 100 / HWEIGHT_WHOLE
178            self.usages.append(upct)
179            self.usage = max(self.usage, upct)
180
181    def dict(self, now, path):
182        out = { 'cgroup'                : path,
183                'timestamp'             : now,
184                'is_active'             : self.is_active,
185                'weight'                : self.weight,
186                'weight_active'         : self.active,
187                'weight_inuse'          : self.inuse,
188                'hweight_active_pct'    : self.hwa_pct,
189                'hweight_inuse_pct'     : self.hwi_pct,
190                'inflight_pct'          : self.inflight_pct,
191                'debt_ms'               : self.debt_ms,
192                'use_delay'             : self.use_delay,
193                'delay_ms'              : self.delay_ms,
194                'usage_pct'             : self.usage,
195                'address'               : self.address }
196        for i in range(len(self.usages)):
197            out[f'usage_pct_{i}'] = str(self.usages[i])
198        return out
199
200    def table_row_str(self, path):
201        out = f'{path[-28:]:28} ' \
202              f'{"*" if self.is_active else " "} ' \
203              f'{self.inuse:5}/{self.active:5} ' \
204              f'{self.hwi_pct:6.2f}/{self.hwa_pct:6.2f} ' \
205              f'{self.inflight_pct:6.2f} ' \
206              f'{min(math.ceil(self.debt_ms), 999):3} ' \
207              f'{min(self.use_delay, 99):2}*'\
208              f'{min(math.ceil(self.delay_ms), 999):03} '
209        for u in self.usages:
210            out += f'{min(round(u), 999):03d}:'
211        out = out.rstrip(':')
212        return out
213
214# handle args
215table_fmt = not args.json
216interval = args.interval
217devname = args.devname
218
219if args.json:
220    table_fmt = False
221
222re_str = None
223if args.cgroup:
224    for r in args.cgroup:
225        if re_str is None:
226            re_str = r
227        else:
228            re_str += '|' + r
229
230filter_re = re.compile(re_str) if re_str else None
231
232# Locate the roots
233q_id = None
234root_iocg = None
235ioc = None
236
237for i, ptr in radix_tree_for_each(blkcg_root.blkg_tree.address_of_()):
238    blkg = drgn.Object(prog, 'struct blkcg_gq', address=ptr)
239    try:
240        if devname == blkg.q.kobj.parent.name.string_().decode('utf-8'):
241            q_id = blkg.q.id.value_()
242            if blkg.pd[plid]:
243                root_iocg = container_of(blkg.pd[plid], 'struct ioc_gq', 'pd')
244                ioc = root_iocg.ioc
245            break
246    except:
247        pass
248
249if ioc is None:
250    err(f'Could not find ioc for {devname}');
251
252if interval == 0:
253    sys.exit(0)
254
255# Keep printing
256while True:
257    now = time.time()
258    iocstat = IocStat(ioc)
259    output = ''
260
261    if table_fmt:
262        output += '\n' + iocstat.table_preamble_str()
263        output += '\n' + iocstat.table_header_str()
264    else:
265        output += json.dumps(iocstat.dict(now))
266
267    for path, blkg in BlkgIterator(blkcg_root, q_id):
268        if filter_re and not filter_re.match(path):
269            continue
270        if not blkg.pd[plid]:
271            continue
272
273        iocg = container_of(blkg.pd[plid], 'struct ioc_gq', 'pd')
274        iocg_stat = IocgStat(iocg)
275
276        if not filter_re and not iocg_stat.is_active:
277            continue
278
279        if table_fmt:
280            output += '\n' + iocg_stat.table_row_str(path)
281        else:
282            output += '\n' + json.dumps(iocg_stat.dict(now, path))
283
284    print(output)
285    sys.stdout.flush()
286    time.sleep(interval)
287