anonymousland-synapse/synapse/metrics/__init__.py
Ivan Shapovalov ac481a738e
synapse.metrics: implement detailed memory usage reporting on PyPy (#7536)
PyPy's gc.get_stats() returns an object containing detailed allocator statistics
which could be beneficial to collect as metrics.

Signed-off-by: Ivan Shapovalov <intelfx@intelfx.name>
2020-05-22 11:08:41 +01:00

580 lines
18 KiB
Python

# -*- coding: utf-8 -*-
# Copyright 2015, 2016 OpenMarket Ltd
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
import functools
import gc
import logging
import os
import platform
import threading
import time
from typing import Callable, Dict, Iterable, Optional, Tuple, Union
import six
import attr
from prometheus_client import Counter, Gauge, Histogram
from prometheus_client.core import (
REGISTRY,
CounterMetricFamily,
GaugeMetricFamily,
HistogramMetricFamily,
)
from twisted.internet import reactor
import synapse
from synapse.metrics._exposition import (
MetricsResource,
generate_latest,
start_http_server,
)
from synapse.util.versionstring import get_version_string
logger = logging.getLogger(__name__)
METRICS_PREFIX = "/_synapse/metrics"
running_on_pypy = platform.python_implementation() == "PyPy"
all_gauges = {} # type: Dict[str, Union[LaterGauge, InFlightGauge, BucketCollector]]
HAVE_PROC_SELF_STAT = os.path.exists("/proc/self/stat")
class RegistryProxy(object):
@staticmethod
def collect():
for metric in REGISTRY.collect():
if not metric.name.startswith("__"):
yield metric
@attr.s(hash=True)
class LaterGauge(object):
name = attr.ib(type=str)
desc = attr.ib(type=str)
labels = attr.ib(hash=False, type=Optional[Iterable[str]])
# callback: should either return a value (if there are no labels for this metric),
# or dict mapping from a label tuple to a value
caller = attr.ib(type=Callable[[], Union[Dict[Tuple[str, ...], float], float]])
def collect(self):
g = GaugeMetricFamily(self.name, self.desc, labels=self.labels)
try:
calls = self.caller()
except Exception:
logger.exception("Exception running callback for LaterGauge(%s)", self.name)
yield g
return
if isinstance(calls, dict):
for k, v in six.iteritems(calls):
g.add_metric(k, v)
else:
g.add_metric([], calls)
yield g
def __attrs_post_init__(self):
self._register()
def _register(self):
if self.name in all_gauges.keys():
logger.warning("%s already registered, reregistering" % (self.name,))
REGISTRY.unregister(all_gauges.pop(self.name))
REGISTRY.register(self)
all_gauges[self.name] = self
class InFlightGauge(object):
"""Tracks number of things (e.g. requests, Measure blocks, etc) in flight
at any given time.
Each InFlightGauge will create a metric called `<name>_total` that counts
the number of in flight blocks, as well as a metrics for each item in the
given `sub_metrics` as `<name>_<sub_metric>` which will get updated by the
callbacks.
Args:
name (str)
desc (str)
labels (list[str])
sub_metrics (list[str]): A list of sub metrics that the callbacks
will update.
"""
def __init__(self, name, desc, labels, sub_metrics):
self.name = name
self.desc = desc
self.labels = labels
self.sub_metrics = sub_metrics
# Create a class which have the sub_metrics values as attributes, which
# default to 0 on initialization. Used to pass to registered callbacks.
self._metrics_class = attr.make_class(
"_MetricsEntry", attrs={x: attr.ib(0) for x in sub_metrics}, slots=True
)
# Counts number of in flight blocks for a given set of label values
self._registrations = {} # type: Dict
# Protects access to _registrations
self._lock = threading.Lock()
self._register_with_collector()
def register(self, key, callback):
"""Registers that we've entered a new block with labels `key`.
`callback` gets called each time the metrics are collected. The same
value must also be given to `unregister`.
`callback` gets called with an object that has an attribute per
sub_metric, which should be updated with the necessary values. Note that
the metrics object is shared between all callbacks registered with the
same key.
Note that `callback` may be called on a separate thread.
"""
with self._lock:
self._registrations.setdefault(key, set()).add(callback)
def unregister(self, key, callback):
"""Registers that we've exited a block with labels `key`.
"""
with self._lock:
self._registrations.setdefault(key, set()).discard(callback)
def collect(self):
"""Called by prometheus client when it reads metrics.
Note: may be called by a separate thread.
"""
in_flight = GaugeMetricFamily(
self.name + "_total", self.desc, labels=self.labels
)
metrics_by_key = {}
# We copy so that we don't mutate the list while iterating
with self._lock:
keys = list(self._registrations)
for key in keys:
with self._lock:
callbacks = set(self._registrations[key])
in_flight.add_metric(key, len(callbacks))
metrics = self._metrics_class()
metrics_by_key[key] = metrics
for callback in callbacks:
callback(metrics)
yield in_flight
for name in self.sub_metrics:
gauge = GaugeMetricFamily(
"_".join([self.name, name]), "", labels=self.labels
)
for key, metrics in six.iteritems(metrics_by_key):
gauge.add_metric(key, getattr(metrics, name))
yield gauge
def _register_with_collector(self):
if self.name in all_gauges.keys():
logger.warning("%s already registered, reregistering" % (self.name,))
REGISTRY.unregister(all_gauges.pop(self.name))
REGISTRY.register(self)
all_gauges[self.name] = self
@attr.s(hash=True)
class BucketCollector(object):
"""
Like a Histogram, but allows buckets to be point-in-time instead of
incrementally added to.
Args:
name (str): Base name of metric to be exported to Prometheus.
data_collector (callable -> dict): A synchronous callable that
returns a dict mapping bucket to number of items in the
bucket. If these buckets are not the same as the buckets
given to this class, they will be remapped into them.
buckets (list[float]): List of floats/ints of the buckets to
give to Prometheus. +Inf is ignored, if given.
"""
name = attr.ib()
data_collector = attr.ib()
buckets = attr.ib()
def collect(self):
# Fetch the data -- this must be synchronous!
data = self.data_collector()
buckets = {} # type: Dict[float, int]
res = []
for x in data.keys():
for i, bound in enumerate(self.buckets):
if x <= bound:
buckets[bound] = buckets.get(bound, 0) + data[x]
for i in self.buckets:
res.append([str(i), buckets.get(i, 0)])
res.append(["+Inf", sum(data.values())])
metric = HistogramMetricFamily(
self.name, "", buckets=res, sum_value=sum(x * y for x, y in data.items())
)
yield metric
def __attrs_post_init__(self):
self.buckets = [float(x) for x in self.buckets if x != "+Inf"]
if self.buckets != sorted(self.buckets):
raise ValueError("Buckets not sorted")
self.buckets = tuple(self.buckets)
if self.name in all_gauges.keys():
logger.warning("%s already registered, reregistering" % (self.name,))
REGISTRY.unregister(all_gauges.pop(self.name))
REGISTRY.register(self)
all_gauges[self.name] = self
#
# Detailed CPU metrics
#
class CPUMetrics(object):
def __init__(self):
ticks_per_sec = 100
try:
# Try and get the system config
ticks_per_sec = os.sysconf("SC_CLK_TCK")
except (ValueError, TypeError, AttributeError):
pass
self.ticks_per_sec = ticks_per_sec
def collect(self):
if not HAVE_PROC_SELF_STAT:
return
with open("/proc/self/stat") as s:
line = s.read()
raw_stats = line.split(") ", 1)[1].split(" ")
user = GaugeMetricFamily("process_cpu_user_seconds_total", "")
user.add_metric([], float(raw_stats[11]) / self.ticks_per_sec)
yield user
sys = GaugeMetricFamily("process_cpu_system_seconds_total", "")
sys.add_metric([], float(raw_stats[12]) / self.ticks_per_sec)
yield sys
REGISTRY.register(CPUMetrics())
#
# Python GC metrics
#
gc_unreachable = Gauge("python_gc_unreachable_total", "Unreachable GC objects", ["gen"])
gc_time = Histogram(
"python_gc_time",
"Time taken to GC (sec)",
["gen"],
buckets=[
0.0025,
0.005,
0.01,
0.025,
0.05,
0.10,
0.25,
0.50,
1.00,
2.50,
5.00,
7.50,
15.00,
30.00,
45.00,
60.00,
],
)
class GCCounts(object):
def collect(self):
cm = GaugeMetricFamily("python_gc_counts", "GC object counts", labels=["gen"])
for n, m in enumerate(gc.get_count()):
cm.add_metric([str(n)], m)
yield cm
if not running_on_pypy:
REGISTRY.register(GCCounts())
#
# PyPy GC / memory metrics
#
class PyPyGCStats(object):
def collect(self):
# @stats is a pretty-printer object with __str__() returning a nice table,
# plus some fields that contain data from that table.
# unfortunately, fields are pretty-printed themselves (i. e. '4.5MB').
stats = gc.get_stats(memory_pressure=False) # type: ignore
# @s contains same fields as @stats, but as actual integers.
s = stats._s # type: ignore
# also note that field naming is completely braindead
# and only vaguely correlates with the pretty-printed table.
# >>>> gc.get_stats(False)
# Total memory consumed:
# GC used: 8.7MB (peak: 39.0MB) # s.total_gc_memory, s.peak_memory
# in arenas: 3.0MB # s.total_arena_memory
# rawmalloced: 1.7MB # s.total_rawmalloced_memory
# nursery: 4.0MB # s.nursery_size
# raw assembler used: 31.0kB # s.jit_backend_used
# -----------------------------
# Total: 8.8MB # stats.memory_used_sum
#
# Total memory allocated:
# GC allocated: 38.7MB (peak: 41.1MB) # s.total_allocated_memory, s.peak_allocated_memory
# in arenas: 30.9MB # s.peak_arena_memory
# rawmalloced: 4.1MB # s.peak_rawmalloced_memory
# nursery: 4.0MB # s.nursery_size
# raw assembler allocated: 1.0MB # s.jit_backend_allocated
# -----------------------------
# Total: 39.7MB # stats.memory_allocated_sum
#
# Total time spent in GC: 0.073 # s.total_gc_time
pypy_gc_time = CounterMetricFamily(
"pypy_gc_time_seconds_total", "Total time spent in PyPy GC", labels=[],
)
pypy_gc_time.add_metric([], s.total_gc_time / 1000)
yield pypy_gc_time
pypy_mem = GaugeMetricFamily(
"pypy_memory_bytes",
"Memory tracked by PyPy allocator",
labels=["state", "class", "kind"],
)
# memory used by JIT assembler
pypy_mem.add_metric(["used", "", "jit"], s.jit_backend_used)
pypy_mem.add_metric(["allocated", "", "jit"], s.jit_backend_allocated)
# memory used by GCed objects
pypy_mem.add_metric(["used", "", "arenas"], s.total_arena_memory)
pypy_mem.add_metric(["allocated", "", "arenas"], s.peak_arena_memory)
pypy_mem.add_metric(["used", "", "rawmalloced"], s.total_rawmalloced_memory)
pypy_mem.add_metric(["allocated", "", "rawmalloced"], s.peak_rawmalloced_memory)
pypy_mem.add_metric(["used", "", "nursery"], s.nursery_size)
pypy_mem.add_metric(["allocated", "", "nursery"], s.nursery_size)
# totals
pypy_mem.add_metric(["used", "totals", "gc"], s.total_gc_memory)
pypy_mem.add_metric(["allocated", "totals", "gc"], s.total_allocated_memory)
pypy_mem.add_metric(["used", "totals", "gc_peak"], s.peak_memory)
pypy_mem.add_metric(["allocated", "totals", "gc_peak"], s.peak_allocated_memory)
yield pypy_mem
if running_on_pypy:
REGISTRY.register(PyPyGCStats())
#
# Twisted reactor metrics
#
tick_time = Histogram(
"python_twisted_reactor_tick_time",
"Tick time of the Twisted reactor (sec)",
buckets=[0.001, 0.002, 0.005, 0.01, 0.025, 0.05, 0.1, 0.2, 0.5, 1, 2, 5],
)
pending_calls_metric = Histogram(
"python_twisted_reactor_pending_calls",
"Pending calls",
buckets=[1, 2, 5, 10, 25, 50, 100, 250, 500, 1000],
)
#
# Federation Metrics
#
sent_transactions_counter = Counter("synapse_federation_client_sent_transactions", "")
events_processed_counter = Counter("synapse_federation_client_events_processed", "")
event_processing_loop_counter = Counter(
"synapse_event_processing_loop_count", "Event processing loop iterations", ["name"]
)
event_processing_loop_room_count = Counter(
"synapse_event_processing_loop_room_count",
"Rooms seen per event processing loop iteration",
["name"],
)
# Used to track where various components have processed in the event stream,
# e.g. federation sending, appservice sending, etc.
event_processing_positions = Gauge("synapse_event_processing_positions", "", ["name"])
# Used to track the current max events stream position
event_persisted_position = Gauge("synapse_event_persisted_position", "")
# Used to track the received_ts of the last event processed by various
# components
event_processing_last_ts = Gauge("synapse_event_processing_last_ts", "", ["name"])
# Used to track the lag processing events. This is the time difference
# between the last processed event's received_ts and the time it was
# finished being processed.
event_processing_lag = Gauge("synapse_event_processing_lag", "", ["name"])
# Build info of the running server.
build_info = Gauge(
"synapse_build_info", "Build information", ["pythonversion", "version", "osversion"]
)
build_info.labels(
" ".join([platform.python_implementation(), platform.python_version()]),
get_version_string(synapse),
" ".join([platform.system(), platform.release()]),
).set(1)
last_ticked = time.time()
class ReactorLastSeenMetric(object):
def collect(self):
cm = GaugeMetricFamily(
"python_twisted_reactor_last_seen",
"Seconds since the Twisted reactor was last seen",
)
cm.add_metric([], time.time() - last_ticked)
yield cm
REGISTRY.register(ReactorLastSeenMetric())
def runUntilCurrentTimer(func):
@functools.wraps(func)
def f(*args, **kwargs):
now = reactor.seconds()
num_pending = 0
# _newTimedCalls is one long list of *all* pending calls. Below loop
# is based off of impl of reactor.runUntilCurrent
for delayed_call in reactor._newTimedCalls:
if delayed_call.time > now:
break
if delayed_call.delayed_time > 0:
continue
num_pending += 1
num_pending += len(reactor.threadCallQueue)
start = time.time()
ret = func(*args, **kwargs)
end = time.time()
# record the amount of wallclock time spent running pending calls.
# This is a proxy for the actual amount of time between reactor polls,
# since about 25% of time is actually spent running things triggered by
# I/O events, but that is harder to capture without rewriting half the
# reactor.
tick_time.observe(end - start)
pending_calls_metric.observe(num_pending)
# Update the time we last ticked, for the metric to test whether
# Synapse's reactor has frozen
global last_ticked
last_ticked = end
if running_on_pypy:
return ret
# Check if we need to do a manual GC (since its been disabled), and do
# one if necessary.
threshold = gc.get_threshold()
counts = gc.get_count()
for i in (2, 1, 0):
if threshold[i] < counts[i]:
if i == 0:
logger.debug("Collecting gc %d", i)
else:
logger.info("Collecting gc %d", i)
start = time.time()
unreachable = gc.collect(i)
end = time.time()
gc_time.labels(i).observe(end - start)
gc_unreachable.labels(i).set(unreachable)
return ret
return f
try:
# Ensure the reactor has all the attributes we expect
reactor.runUntilCurrent
reactor._newTimedCalls
reactor.threadCallQueue
# runUntilCurrent is called when we have pending calls. It is called once
# per iteratation after fd polling.
reactor.runUntilCurrent = runUntilCurrentTimer(reactor.runUntilCurrent)
# We manually run the GC each reactor tick so that we can get some metrics
# about time spent doing GC,
if not running_on_pypy:
gc.disable()
except AttributeError:
pass
__all__ = [
"MetricsResource",
"generate_latest",
"start_http_server",
"LaterGauge",
"InFlightGauge",
"BucketCollector",
]