@@ -149,6 +149,27 @@
* 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/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>
new file mode 100644
@@ -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)
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> --- block/blk-iocost.c | 21 +++ tools/cgroup/iocost_monitor.py | 270 +++++++++++++++++++++++++++++++++ 2 files changed, 291 insertions(+) create mode 100644 tools/cgroup/iocost_monitor.py