Instead of mucking with debugfs and ->pd_stat(), add drgn based monitoring script. Signed-off-by: Tejun Heo <tj@xxxxxxxxxx> Cc: Omar Sandoval <osandov@xxxxxx> --- block/blk-ioweight.c | 21 +++ tools/cgroup/monitor_ioweight.py | 264 +++++++++++++++++++++++++++++++ 2 files changed, 285 insertions(+) create mode 100644 tools/cgroup/monitor_ioweight.py diff --git a/block/blk-ioweight.c b/block/blk-ioweight.c index d10249f5774e..3d9fc1a631be 100644 --- a/block/blk-ioweight.c +++ b/block/blk-ioweight.c @@ -146,6 +146,27 @@ * donate and should take back how much requires hweight propagations * anyway making it easier to implement and understand as a separate * mechanism. + * + * 3. Monitoring + * + * Instead of debugfs or other clumsy monitoring mechanisms, this + * controller uses a drgn based monitoring script - + * tools/cgroup/monitor_ioweight.py. For details on drgn, please see + * https://github.com/osandov/drgn. The ouput looks like the following. + * + * sdb RUN per=300ms cur_per=234.218:v203.695 busy= +1 vrate= 62.12% + * active weight hweight% inflt% del_ms usages% + * test/a * 50/ 50 33.33/ 33.33 27.65 0*041 033:033:033 + * test/b * 100/ 100 66.67/ 66.67 17.56 0*000 066:079:077 + * + * - per : Timer period + * - cur_per : Internal wall and device vtime clock + * - vrate : Device virtual time rate against wall clock + * - weight : Surplus-adjusted and configured weights + * - hweight : Surplus-adjusted and configured hierarchical weights + * - inflt : The percentage of in-flight IO cost at the end of last period + * - del_ms : Deferred issuer delay induction level and duration + * - usages : Usage history */ #include <linux/kernel.h> diff --git a/tools/cgroup/monitor_ioweight.py b/tools/cgroup/monitor_ioweight.py new file mode 100644 index 000000000000..3cd432772e52 --- /dev/null +++ b/tools/cgroup/monitor_ioweight.py @@ -0,0 +1,264 @@ +#!/usr/bin/env -S drgn -k +# +# This is a drgn script to monitor the blk-ioweight cgroup controller. +# See the comment at the top of block/blk-ioweight.c for more details. +# For drgn, visit https://github.com/osandov/drgn. +# + +import sys +import re +import time +import json + +import drgn +from drgn import container_of +from drgn.helpers.linux.list import list_for_each_entry,list_empty +from drgn.helpers.linux.radixtree import radix_tree_for_each,radix_tree_lookup + +import argparse +parser = argparse.ArgumentParser() +parser.add_argument('devname', metavar='DEV', + help='Target block device name (e.g. sda)') +parser.add_argument('--cgroup', action='append', metavar='REGEX', + help='Regex for target cgroups, ') +parser.add_argument('--interval', '-i', metavar='SECONDS', type=float, default=1, + help='Monitoring interval in seconds') +parser.add_argument('--json', action='store_true', + help='Output in json') +args = parser.parse_args() + +def err(s): + print(s, file=sys.stderr, flush=True) + sys.exit(1) + +try: + blkcg_root = prog['blkcg_root'] + plid = prog['blkcg_policy_iow'].plid.value_() +except: + err('The kernel does not have ioweight enabled') + +IOW_RUNNING = prog['IOW_RUNNING'].value_() +NR_USAGE_SLOTS = prog['NR_USAGE_SLOTS'].value_() +HWEIGHT_WHOLE = prog['HWEIGHT_WHOLE'].value_() +VTIME_PER_SEC = prog['VTIME_PER_SEC'].value_() +VTIME_PER_USEC = prog['VTIME_PER_USEC'].value_() +AUTOP_SSD_FAST = prog['AUTOP_SSD_FAST'].value_() +AUTOP_SSD_DFL = prog['AUTOP_SSD_DFL'].value_() +AUTOP_SSD_QD1 = prog['AUTOP_SSD_QD1'].value_() +AUTOP_HDD = prog['AUTOP_HDD'].value_() + +autop_names = { + AUTOP_SSD_FAST: 'ssd_fast', + AUTOP_SSD_DFL: 'ssd_dfl', + AUTOP_SSD_QD1: 'ssd_qd1', + AUTOP_HDD: 'hdd', +} + +class BlkgIterator: + def blkcg_name(blkcg): + return blkcg.css.cgroup.kn.name.string_().decode('utf-8') + + def walk(self, blkcg, q_id, parent_path): + if not self.include_dying and \ + not (blkcg.css.flags.value_() & prog['CSS_ONLINE'].value_()): + return + + name = BlkgIterator.blkcg_name(blkcg) + path = parent_path + '/' + name if parent_path else name + blkg = drgn.Object(prog, 'struct blkcg_gq', + address=radix_tree_lookup(blkcg.blkg_tree, q_id)) + if not blkg.address_: + return + + self.blkgs.append((path if path else '/', blkg)) + + for c in list_for_each_entry('struct blkcg', + blkcg.css.children.address_of_(), 'css.sibling'): + self.walk(c, q_id, path) + + def __init__(self, root_blkcg, q_id, include_dying=False): + self.include_dying = include_dying + self.blkgs = [] + self.walk(root_blkcg, q_id, '') + + def __iter__(self): + return iter(self.blkgs) + +class IowStat: + def __init__(self, iow): + global autop_names + + self.enabled = iow.enabled.value_() + self.running = iow.running.value_() == IOW_RUNNING + self.period_ms = round(iow.period_us.value_() / 1_000) + self.period_at = iow.period_at.value_() / 1_000_000 + self.vperiod_at = iow.period_at_vtime.value_() / VTIME_PER_SEC + self.vrate_pct = iow.vtime_rate.counter.value_() * 100 / VTIME_PER_USEC + self.busy_level = iow.busy_level.value_() + self.autop_idx = iow.autop_idx.value_() + self.user_cost_model = iow.user_cost_model.value_() + self.user_qos_params = iow.user_qos_params.value_() + + if self.autop_idx in autop_names: + self.autop_name = autop_names[self.autop_idx] + else: + self.autop_name = '?' + + def dict(self, now): + return { 'device' : devname, + 'timestamp' : now, + 'enabled' : self.enabled, + 'running' : self.running, + 'period_ms' : self.period_ms, + 'period_at' : self.period_at, + 'period_vtime_at' : self.vperiod_at, + 'busy_level' : self.busy_level, + 'vrate_pct' : self.vrate_pct, } + + def table_preamble_str(self): + state = ('RUN' if self.running else 'IDLE') if self.enabled else 'OFF' + output = f'{devname} {state:4} ' \ + f'per={self.period_ms}ms ' \ + f'cur_per={self.period_at:.3f}:v{self.vperiod_at:.3f} ' \ + f'busy={self.busy_level:+3} ' \ + f'vrate={self.vrate_pct:6.2f}% ' \ + f'params={self.autop_name}' + if self.user_cost_model or self.user_qos_params: + output += f'({"C" if self.user_cost_model else ""}{"Q" if self.user_qos_params else ""})' + return output + + def table_header_str(self): + return f'{"":25} active {"weight":>9} {"hweight%":>13} {"inflt%":>6} ' \ + f'{"del_ms":>6} {"usages%"}' + +class IowgStat: + def __init__(self, iowg): + iow = iowg.iow + blkg = iowg.pd.blkg + + self.is_active = not list_empty(iowg.active_list.address_of_()) + self.weight = iowg.weight.value_() + self.active = iowg.active.value_() + self.inuse = iowg.inuse.value_() + self.hwa_pct = iowg.hweight_active.value_() * 100 / HWEIGHT_WHOLE + self.hwi_pct = iowg.hweight_inuse.value_() * 100 / HWEIGHT_WHOLE + + vdone = iowg.done_vtime.counter.value_() + vtime = iowg.vtime.counter.value_() + vrate = iow.vtime_rate.counter.value_() + period_vtime = iow.period_us.value_() * vrate + if period_vtime: + self.inflight_pct = (vtime - vdone) * 100 / period_vtime + else: + self.inflight_pct = 0 + + self.use_delay = min(blkg.use_delay.counter.value_(), 99) + self.delay_ms = min(round(blkg.delay_nsec.counter.value_() / 1_000_000), 999) + + usage_idx = iowg.usage_idx.value_() + self.usages = [] + self.usage = 0 + for i in range(NR_USAGE_SLOTS): + usage = iowg.usages[(usage_idx + i) % NR_USAGE_SLOTS].value_() + upct = min(usage * 100 / HWEIGHT_WHOLE, 999) + self.usages.append(upct) + self.usage = max(self.usage, upct) + + def dict(self, now, path): + out = { 'cgroup' : path, + 'timestamp' : now, + 'is_active' : self.is_active, + 'weight' : self.weight, + 'weight_active' : self.active, + 'weight_inuse' : self.inuse, + 'hweight_active_pct' : self.hwa_pct, + 'hweight_inuse_pct' : self.hwi_pct, + 'inflight_pct' : self.inflight_pct, + 'use_delay' : self.use_delay, + 'delay_ms' : self.delay_ms, + 'usage_pct' : self.usage } + for i in range(len(self.usages)): + out[f'usage_pct_{i}'] = f'{self.usages[i]}' + return out + + def table_row_str(self, path): + out = f'{path[-28:]:28} ' \ + f'{"*" if self.is_active else " "} ' \ + f'{self.inuse:5}/{self.active:5} ' \ + f'{self.hwi_pct:6.2f}/{self.hwa_pct:6.2f} ' \ + f'{self.inflight_pct:6.2f} ' \ + f'{self.use_delay:2}*{self.delay_ms:03} ' + for u in self.usages: + out += f'{round(u):03d}:' + out = out.rstrip(':') + return out + +# handle args +table_fmt = not args.json +interval = args.interval +devname = args.devname + +if args.json: + table_fmt = False + +re_str = None +for r in args.cgroup: + if re_str is None: + re_str = r + else: + re_str += '|' + r + +filter_re = re.compile(re_str) if re_str else None + +# Locate the roots +q_id = None +root_iowg = None +iow = None + +for i, ptr in radix_tree_for_each(blkcg_root.blkg_tree): + blkg = drgn.Object(prog, 'struct blkcg_gq', address=ptr) + try: + if devname == blkg.q.kobj.parent.name.string_().decode('utf-8'): + q_id = blkg.q.id.value_() + if blkg.pd[plid]: + root_iowg = container_of(blkg.pd[plid], 'struct iow_gq', 'pd') + iow = root_iowg.iow + break + except: + pass + +if iow is None: + err(f'Could not find iow for {devname}'); + +# Keep printing +while True: + now = time.time() + iowstat = IowStat(iow) + output = '' + + if table_fmt: + output += '\n' + iowstat.table_preamble_str() + output += '\n' + iowstat.table_header_str() + else: + output += json.dumps(iowstat.dict(now)) + + for path, blkg in BlkgIterator(blkcg_root, q_id): + if filter_re and not filter_re.match(path): + continue + if not blkg.pd[plid]: + continue + + iowg = container_of(blkg.pd[plid], 'struct iow_gq', 'pd') + iowg_stat = IowgStat(iowg) + + if not filter_re and not iowg_stat.is_active: + continue + + if table_fmt: + output += '\n' + iowg_stat.table_row_str(path) + else: + output += '\n' + json.dumps(iowg_stat.dict(now, path)) + + print(output) + sys.stdout.flush() + time.sleep(interval) -- 2.17.1
