diff --git a/synapse/util/caches/__init__.py b/synapse/util/caches/__init__.py
index da5077b471..4b8a0c7a8f 100644
--- a/synapse/util/caches/__init__.py
+++ b/synapse/util/caches/__init__.py
@@ -1,6 +1,6 @@
# -*- coding: utf-8 -*-
# Copyright 2015, 2016 OpenMarket Ltd
-# Copyright 2019 The Matrix.org Foundation C.I.C.
+# Copyright 2019, 2020 The Matrix.org Foundation C.I.C.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
@@ -15,27 +15,17 @@
# limitations under the License.
import logging
-import os
-from typing import Dict
+from typing import Callable, Dict, Optional
import six
from six.moves import intern
-from prometheus_client.core import REGISTRY, Gauge, GaugeMetricFamily
-
-logger = logging.getLogger(__name__)
-
-CACHE_SIZE_FACTOR = float(os.environ.get("SYNAPSE_CACHE_FACTOR", 0.5))
+import attr
+from prometheus_client.core import Gauge
+from synapse.config.cache import add_resizable_cache
-def get_cache_factor_for(cache_name):
- env_var = "SYNAPSE_CACHE_FACTOR_" + cache_name.upper()
- factor = os.environ.get(env_var)
- if factor:
- return float(factor)
-
- return CACHE_SIZE_FACTOR
-
+logger = logging.getLogger(__name__)
caches_by_name = {}
collectors_by_name = {} # type: Dict
@@ -44,6 +34,7 @@ cache_size = Gauge("synapse_util_caches_cache:size", "", ["name"])
cache_hits = Gauge("synapse_util_caches_cache:hits", "", ["name"])
cache_evicted = Gauge("synapse_util_caches_cache:evicted_size", "", ["name"])
cache_total = Gauge("synapse_util_caches_cache:total", "", ["name"])
+cache_max_size = Gauge("synapse_util_caches_cache_max_size", "", ["name"])
response_cache_size = Gauge("synapse_util_caches_response_cache:size", "", ["name"])
response_cache_hits = Gauge("synapse_util_caches_response_cache:hits", "", ["name"])
@@ -53,67 +44,82 @@ response_cache_evicted = Gauge(
response_cache_total = Gauge("synapse_util_caches_response_cache:total", "", ["name"])
-def register_cache(cache_type, cache_name, cache, collect_callback=None):
- """Register a cache object for metric collection.
+@attr.s
+class CacheMetric(object):
+
+ _cache = attr.ib()
+ _cache_type = attr.ib(type=str)
+ _cache_name = attr.ib(type=str)
+ _collect_callback = attr.ib(type=Optional[Callable])
+
+ hits = attr.ib(default=0)
+ misses = attr.ib(default=0)
+ evicted_size = attr.ib(default=0)
+
+ def inc_hits(self):
+ self.hits += 1
+
+ def inc_misses(self):
+ self.misses += 1
+
+ def inc_evictions(self, size=1):
+ self.evicted_size += size
+
+ def describe(self):
+ return []
+
+ def collect(self):
+ try:
+ if self._cache_type == "response_cache":
+ response_cache_size.labels(self._cache_name).set(len(self._cache))
+ response_cache_hits.labels(self._cache_name).set(self.hits)
+ response_cache_evicted.labels(self._cache_name).set(self.evicted_size)
+ response_cache_total.labels(self._cache_name).set(
+ self.hits + self.misses
+ )
+ else:
+ cache_size.labels(self._cache_name).set(len(self._cache))
+ cache_hits.labels(self._cache_name).set(self.hits)
+ cache_evicted.labels(self._cache_name).set(self.evicted_size)
+ cache_total.labels(self._cache_name).set(self.hits + self.misses)
+ if getattr(self._cache, "max_size", None):
+ cache_max_size.labels(self._cache_name).set(self._cache.max_size)
+ if self._collect_callback:
+ self._collect_callback()
+ except Exception as e:
+ logger.warning("Error calculating metrics for %s: %s", self._cache_name, e)
+ raise
+
+
+def register_cache(
+ cache_type: str,
+ cache_name: str,
+ cache,
+ collect_callback: Optional[Callable] = None,
+ resizable: bool = True,
+ resize_callback: Optional[Callable] = None,
+) -> CacheMetric:
+ """Register a cache object for metric collection and resizing.
Args:
- cache_type (str):
- cache_name (str): name of the cache
- cache (object): cache itself
- collect_callback (callable|None): if not None, a function which is called during
- metric collection to update additional metrics.
+ cache_type
+ cache_name: name of the cache
+ cache: cache itself
+ collect_callback: If given, a function which is called during metric
+ collection to update additional metrics.
+ resizable: Whether this cache supports being resized.
+ resize_callback: A function which can be called to resize the cache.
Returns:
CacheMetric: an object which provides inc_{hits,misses,evictions} methods
"""
+ if resizable:
+ if not resize_callback:
+ resize_callback = getattr(cache, "set_cache_factor")
+ add_resizable_cache(cache_name, resize_callback)
- # Check if the metric is already registered. Unregister it, if so.
- # This usually happens during tests, as at runtime these caches are
- # effectively singletons.
+ metric = CacheMetric(cache, cache_type, cache_name, collect_callback)
metric_name = "cache_%s_%s" % (cache_type, cache_name)
- if metric_name in collectors_by_name.keys():
- REGISTRY.unregister(collectors_by_name[metric_name])
-
- class CacheMetric(object):
-
- hits = 0
- misses = 0
- evicted_size = 0
-
- def inc_hits(self):
- self.hits += 1
-
- def inc_misses(self):
- self.misses += 1
-
- def inc_evictions(self, size=1):
- self.evicted_size += size
-
- def describe(self):
- return []
-
- def collect(self):
- try:
- if cache_type == "response_cache":
- response_cache_size.labels(cache_name).set(len(cache))
- response_cache_hits.labels(cache_name).set(self.hits)
- response_cache_evicted.labels(cache_name).set(self.evicted_size)
- response_cache_total.labels(cache_name).set(self.hits + self.misses)
- else:
- cache_size.labels(cache_name).set(len(cache))
- cache_hits.labels(cache_name).set(self.hits)
- cache_evicted.labels(cache_name).set(self.evicted_size)
- cache_total.labels(cache_name).set(self.hits + self.misses)
- if collect_callback:
- collect_callback()
- except Exception as e:
- logger.warning("Error calculating metrics for %s: %s", cache_name, e)
- raise
-
- yield GaugeMetricFamily("__unused", "")
-
- metric = CacheMetric()
- REGISTRY.register(metric)
caches_by_name[cache_name] = cache
collectors_by_name[metric_name] = metric
return metric
diff --git a/synapse/util/caches/descriptors.py b/synapse/util/caches/descriptors.py
index 2e8f6543e5..cd48262420 100644
--- a/synapse/util/caches/descriptors.py
+++ b/synapse/util/caches/descriptors.py
@@ -13,6 +13,7 @@
# 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 inspect
import logging
@@ -30,7 +31,6 @@ from twisted.internet import defer
from synapse.logging.context import make_deferred_yieldable, preserve_fn
from synapse.util import unwrapFirstError
from synapse.util.async_helpers import ObservableDeferred
-from synapse.util.caches import get_cache_factor_for
from synapse.util.caches.lrucache import LruCache
from synapse.util.caches.treecache import TreeCache, iterate_tree_cache_entry
@@ -81,7 +81,6 @@ class CacheEntry(object):
class Cache(object):
__slots__ = (
"cache",
- "max_entries",
"name",
"keylen",
"thread",
@@ -89,7 +88,29 @@ class Cache(object):
"_pending_deferred_cache",
)
- def __init__(self, name, max_entries=1000, keylen=1, tree=False, iterable=False):
+ def __init__(
+ self,
+ name: str,
+ max_entries: int = 1000,
+ keylen: int = 1,
+ tree: bool = False,
+ iterable: bool = False,
+ apply_cache_factor_from_config: bool = True,
+ ):
+ """
+ Args:
+ name: The name of the cache
+ max_entries: Maximum amount of entries that the cache will hold
+ keylen: The length of the tuple used as the cache key
+ tree: Use a TreeCache instead of a dict as the underlying cache type
+ iterable: If True, count each item in the cached object as an entry,
+ rather than each cached object
+ apply_cache_factor_from_config: Whether cache factors specified in the
+ config file affect `max_entries`
+
+ Returns:
+ Cache
+ """
cache_type = TreeCache if tree else dict
self._pending_deferred_cache = cache_type()
@@ -99,6 +120,7 @@ class Cache(object):
cache_type=cache_type,
size_callback=(lambda d: len(d)) if iterable else None,
evicted_callback=self._on_evicted,
+ apply_cache_factor_from_config=apply_cache_factor_from_config,
)
self.name = name
@@ -111,6 +133,10 @@ class Cache(object):
collect_callback=self._metrics_collection_callback,
)
+ @property
+ def max_entries(self):
+ return self.cache.max_size
+
def _on_evicted(self, evicted_count):
self.metrics.inc_evictions(evicted_count)
@@ -370,13 +396,11 @@ class CacheDescriptor(_CacheDescriptorBase):
cache_context=cache_context,
)
- max_entries = int(max_entries * get_cache_factor_for(orig.__name__))
-
self.max_entries = max_entries
self.tree = tree
self.iterable = iterable
- def __get__(self, obj, objtype=None):
+ def __get__(self, obj, owner):
cache = Cache(
name=self.orig.__name__,
max_entries=self.max_entries,
diff --git a/synapse/util/caches/expiringcache.py b/synapse/util/caches/expiringcache.py
index cddf1ed515..2726b67b6d 100644
--- a/synapse/util/caches/expiringcache.py
+++ b/synapse/util/caches/expiringcache.py
@@ -18,6 +18,7 @@ from collections import OrderedDict
from six import iteritems, itervalues
+from synapse.config import cache as cache_config
from synapse.metrics.background_process_metrics import run_as_background_process
from synapse.util.caches import register_cache
@@ -51,15 +52,16 @@ class ExpiringCache(object):
an item on access. Defaults to False.
iterable (bool): If true, the size is calculated by summing the
sizes of all entries, rather than the number of entries.
-
"""
self._cache_name = cache_name
+ self._original_max_size = max_len
+
+ self._max_size = int(max_len * cache_config.properties.default_factor_size)
+
self._clock = clock
- self._max_len = max_len
self._expiry_ms = expiry_ms
-
self._reset_expiry_on_get = reset_expiry_on_get
self._cache = OrderedDict()
@@ -82,9 +84,11 @@ class ExpiringCache(object):
def __setitem__(self, key, value):
now = self._clock.time_msec()
self._cache[key] = _CacheEntry(now, value)
+ self.evict()
+ def evict(self):
# Evict if there are now too many items
- while self._max_len and len(self) > self._max_len:
+ while self._max_size and len(self) > self._max_size:
_key, value = self._cache.popitem(last=False)
if self.iterable:
self.metrics.inc_evictions(len(value.value))
@@ -170,6 +174,23 @@ class ExpiringCache(object):
else:
return len(self._cache)
+ def set_cache_factor(self, factor: float) -> bool:
+ """
+ Set the cache factor for this individual cache.
+
+ This will trigger a resize if it changes, which may require evicting
+ items from the cache.
+
+ Returns:
+ bool: Whether the cache changed size or not.
+ """
+ new_size = int(self._original_max_size * factor)
+ if new_size != self._max_size:
+ self._max_size = new_size
+ self.evict()
+ return True
+ return False
+
class _CacheEntry(object):
__slots__ = ["time", "value"]
diff --git a/synapse/util/caches/lrucache.py b/synapse/util/caches/lrucache.py
index 1536cb64f3..29fabac3cd 100644
--- a/synapse/util/caches/lrucache.py
+++ b/synapse/util/caches/lrucache.py
@@ -13,10 +13,11 @@
# See the License for the specific language governing permissions and
# limitations under the License.
-
import threading
from functools import wraps
+from typing import Callable, Optional, Type, Union
+from synapse.config import cache as cache_config
from synapse.util.caches.treecache import TreeCache
@@ -52,17 +53,18 @@ class LruCache(object):
def __init__(
self,
- max_size,
- keylen=1,
- cache_type=dict,
- size_callback=None,
- evicted_callback=None,
+ max_size: int,
+ keylen: int = 1,
+ cache_type: Type[Union[dict, TreeCache]] = dict,
+ size_callback: Optional[Callable] = None,
+ evicted_callback: Optional[Callable] = None,
+ apply_cache_factor_from_config: bool = True,
):
"""
Args:
- max_size (int):
+ max_size: The maximum amount of entries the cache can hold
- keylen (int):
+ keylen: The length of the tuple used as the cache key
cache_type (type):
type of underlying cache to be used. Typically one of dict
@@ -73,9 +75,23 @@ class LruCache(object):
evicted_callback (func(int)|None):
if not None, called on eviction with the size of the evicted
entry
+
+ apply_cache_factor_from_config (bool): If true, `max_size` will be
+ multiplied by a cache factor derived from the homeserver config
"""
cache = cache_type()
self.cache = cache # Used for introspection.
+
+ # Save the original max size, and apply the default size factor.
+ self._original_max_size = max_size
+ # We previously didn't apply the cache factor here, and as such some caches were
+ # not affected by the global cache factor. Add an option here to disable applying
+ # the cache factor when a cache is created
+ if apply_cache_factor_from_config:
+ self.max_size = int(max_size * cache_config.properties.default_factor_size)
+ else:
+ self.max_size = int(max_size)
+
list_root = _Node(None, None, None, None)
list_root.next_node = list_root
list_root.prev_node = list_root
@@ -83,7 +99,7 @@ class LruCache(object):
lock = threading.Lock()
def evict():
- while cache_len() > max_size:
+ while cache_len() > self.max_size:
todelete = list_root.prev_node
evicted_len = delete_node(todelete)
cache.pop(todelete.key, None)
@@ -236,6 +252,7 @@ class LruCache(object):
return key in cache
self.sentinel = object()
+ self._on_resize = evict
self.get = cache_get
self.set = cache_set
self.setdefault = cache_set_default
@@ -266,3 +283,20 @@ class LruCache(object):
def __contains__(self, key):
return self.contains(key)
+
+ def set_cache_factor(self, factor: float) -> bool:
+ """
+ Set the cache factor for this individual cache.
+
+ This will trigger a resize if it changes, which may require evicting
+ items from the cache.
+
+ Returns:
+ bool: Whether the cache changed size or not.
+ """
+ new_size = int(self._original_max_size * factor)
+ if new_size != self.max_size:
+ self.max_size = new_size
+ self._on_resize()
+ return True
+ return False
diff --git a/synapse/util/caches/response_cache.py b/synapse/util/caches/response_cache.py
index b68f9fe0d4..a6c60888e5 100644
--- a/synapse/util/caches/response_cache.py
+++ b/synapse/util/caches/response_cache.py
@@ -38,7 +38,7 @@ class ResponseCache(object):
self.timeout_sec = timeout_ms / 1000.0
self._name = name
- self._metrics = register_cache("response_cache", name, self)
+ self._metrics = register_cache("response_cache", name, self, resizable=False)
def size(self):
return len(self.pending_result_cache)
diff --git a/synapse/util/caches/stream_change_cache.py b/synapse/util/caches/stream_change_cache.py
index e54f80d76e..2a161bf244 100644
--- a/synapse/util/caches/stream_change_cache.py
+++ b/synapse/util/caches/stream_change_cache.py
@@ -14,6 +14,7 @@
# limitations under the License.
import logging
+import math
from typing import Dict, FrozenSet, List, Mapping, Optional, Set, Union
from six import integer_types
@@ -46,7 +47,8 @@ class StreamChangeCache:
max_size=10000,
prefilled_cache: Optional[Mapping[EntityType, int]] = None,
):
- self._max_size = int(max_size * caches.CACHE_SIZE_FACTOR)
+ self._original_max_size = max_size
+ self._max_size = math.floor(max_size)
self._entity_to_key = {} # type: Dict[EntityType, int]
# map from stream id to the a set of entities which changed at that stream id.
@@ -58,12 +60,31 @@ class StreamChangeCache:
#
self._earliest_known_stream_pos = current_stream_pos
self.name = name
- self.metrics = caches.register_cache("cache", self.name, self._cache)
+ self.metrics = caches.register_cache(
+ "cache", self.name, self._cache, resize_callback=self.set_cache_factor
+ )
if prefilled_cache:
for entity, stream_pos in prefilled_cache.items():
self.entity_has_changed(entity, stream_pos)
+ def set_cache_factor(self, factor: float) -> bool:
+ """
+ Set the cache factor for this individual cache.
+
+ This will trigger a resize if it changes, which may require evicting
+ items from the cache.
+
+ Returns:
+ bool: Whether the cache changed size or not.
+ """
+ new_size = math.floor(self._original_max_size * factor)
+ if new_size != self._max_size:
+ self.max_size = new_size
+ self._evict()
+ return True
+ return False
+
def has_entity_changed(self, entity: EntityType, stream_pos: int) -> bool:
"""Returns True if the entity may have been updated since stream_pos
"""
@@ -171,6 +192,7 @@ class StreamChangeCache:
e1 = self._cache[stream_pos] = set()
e1.add(entity)
self._entity_to_key[entity] = stream_pos
+ self._evict()
# if the cache is too big, remove entries
while len(self._cache) > self._max_size:
@@ -179,6 +201,13 @@ class StreamChangeCache:
for entity in r:
del self._entity_to_key[entity]
+ def _evict(self):
+ while len(self._cache) > self._max_size:
+ k, r = self._cache.popitem(0)
+ self._earliest_known_stream_pos = max(k, self._earliest_known_stream_pos)
+ for entity in r:
+ self._entity_to_key.pop(entity, None)
+
def get_max_pos_of_last_change(self, entity: EntityType) -> int:
"""Returns an upper bound of the stream id of the last change to an
diff --git a/synapse/util/caches/ttlcache.py b/synapse/util/caches/ttlcache.py
index 99646c7cf0..6437aa907e 100644
--- a/synapse/util/caches/ttlcache.py
+++ b/synapse/util/caches/ttlcache.py
@@ -38,7 +38,7 @@ class TTLCache(object):
self._timer = timer
- self._metrics = register_cache("ttl", cache_name, self)
+ self._metrics = register_cache("ttl", cache_name, self, resizable=False)
def set(self, key, value, ttl):
"""Add/update an entry in the cache
|
