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blkcg: add tools/cgroup/iocost_monitor.py 

Instead of mucking with debugfs and ->pd_stat(), add drgn based
monitoring script.

Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Omar Sandoval <osandov@fb.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This commit is contained in:
Tejun Heo 2019-08-28 15:05:59 -07:00 committed by Jens Axboe
parent 7caa47151a
commit 6954ff185e
2 changed files with 291 additions and 0 deletions
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21
block/blk-iocost.c
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@ -149,6 +149,27 @@
* donate and should take back how much requires hweight propagations * donate and should take back how much requires hweight propagations
* anyway making it easier to implement and understand as a separate * anyway making it easier to implement and understand as a separate
* mechanism. * mechanism.
*
* 3. Monitoring
*
* Instead of debugfs or other clumsy monitoring mechanisms, this
* controller uses a drgn based monitoring script -
* tools/cgroup/iocost_monitor.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> #include <linux/kernel.h>

270
tools/cgroup/iocost_monitor.py Normal file
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@ -0,0 +1,270 @@
#!/usr/bin/env drgn
#
# Copyright (C) 2019 Tejun Heo <tj@kernel.org>
# Copyright (C) 2019 Facebook
desc = """
This is a drgn script to monitor the blk-iocost cgroup controller.
See the comment at the top of block/blk-iocost.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(description=desc,
formatter_class=argparse.RawTextHelpFormatter)
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_iocost'].plid.value_()
except:
err('The kernel does not have iocost enabled')
IOC_RUNNING = prog['IOC_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 IocStat:
def __init__(self, ioc):
global autop_names
self.enabled = ioc.enabled.value_()
self.running = ioc.running.value_() == IOC_RUNNING
self.period_ms = round(ioc.period_us.value_() / 1_000)
self.period_at = ioc.period_at.value_() / 1_000_000
self.vperiod_at = ioc.period_at_vtime.value_() / VTIME_PER_SEC
self.vrate_pct = ioc.vtime_rate.counter.value_() * 100 / VTIME_PER_USEC
self.busy_level = ioc.busy_level.value_()
self.autop_idx = ioc.autop_idx.value_()
self.user_cost_model = ioc.user_cost_model.value_()
self.user_qos_params = ioc.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 IocgStat:
def __init__(self, iocg):
ioc = iocg.ioc
blkg = iocg.pd.blkg
self.is_active = not list_empty(iocg.active_list.address_of_())
self.weight = iocg.weight.value_()
self.active = iocg.active.value_()
self.inuse = iocg.inuse.value_()
self.hwa_pct = iocg.hweight_active.value_() * 100 / HWEIGHT_WHOLE
self.hwi_pct = iocg.hweight_inuse.value_() * 100 / HWEIGHT_WHOLE
vdone = iocg.done_vtime.counter.value_()
vtime = iocg.vtime.counter.value_()
vrate = ioc.vtime_rate.counter.value_()
period_vtime = ioc.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 = iocg.usage_idx.value_()
self.usages = []
self.usage = 0
for i in range(NR_USAGE_SLOTS):
usage = iocg.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
if args.cgroup:
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_iocg = None
ioc = 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_iocg = container_of(blkg.pd[plid], 'struct ioc_gq', 'pd')
ioc = root_iocg.ioc
break
except:
pass
if ioc is None:
err(f'Could not find ioc for {devname}');
# Keep printing
while True:
now = time.time()
iocstat = IocStat(ioc)
output = ''
if table_fmt:
output += '\n' + iocstat.table_preamble_str()
output += '\n' + iocstat.table_header_str()
else:
output += json.dumps(iocstat.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
iocg = container_of(blkg.pd[plid], 'struct ioc_gq', 'pd')
iocg_stat = IocgStat(iocg)
if not filter_re and not iocg_stat.is_active:
continue
if table_fmt:
output += '\n' + iocg_stat.table_row_str(path)
else:
output += '\n' + json.dumps(iocg_stat.dict(now, path))
print(output)
sys.stdout.flush()
time.sleep(interval)