Reduce the number of calls to `resource.getrusage` (#7183)

Let's just call `getrusage` once on each logcontext change, rather than twice.
pull/7193/head
Richard van der Hoff 2020-04-03 13:21:30 +01:00 committed by GitHub
parent fd4c975b5b
commit 0f05fd1530
No known key found for this signature in database
GPG Key ID: 4AEE18F83AFDEB23
2 changed files with 64 additions and 39 deletions

1
changelog.d/7183.misc Normal file
View File

@ -0,0 +1 @@
Clean up some LoggingContext code.

View File

@ -51,7 +51,7 @@ try:
is_thread_resource_usage_supported = True
def get_thread_resource_usage():
def get_thread_resource_usage() -> "Optional[resource._RUsage]":
return resource.getrusage(RUSAGE_THREAD)
@ -60,7 +60,7 @@ except Exception:
# won't track resource usage.
is_thread_resource_usage_supported = False
def get_thread_resource_usage():
def get_thread_resource_usage() -> "Optional[resource._RUsage]":
return None
@ -201,10 +201,10 @@ class _Sentinel(object):
record["request"] = None
record["scope"] = None
def start(self):
def start(self, rusage: "Optional[resource._RUsage]"):
pass
def stop(self):
def stop(self, rusage: "Optional[resource._RUsage]"):
pass
def add_database_transaction(self, duration_sec):
@ -261,7 +261,7 @@ class LoggingContext(object):
# The thread resource usage when the logcontext became active. None
# if the context is not currently active.
self.usage_start = None
self.usage_start = None # type: Optional[resource._RUsage]
self.main_thread = get_thread_id()
self.request = None
@ -336,7 +336,17 @@ class LoggingContext(object):
record["request"] = self.request
record["scope"] = self.scope
def start(self) -> None:
def start(self, rusage: "Optional[resource._RUsage]") -> None:
"""
Record that this logcontext is currently running.
This should not be called directly: use set_current_context
Args:
rusage: the resources used by the current thread, at the point of
switching to this logcontext. May be None if this platform doesn't
support getrusuage.
"""
if get_thread_id() != self.main_thread:
logger.warning("Started logcontext %s on different thread", self)
return
@ -349,36 +359,48 @@ class LoggingContext(object):
if self.usage_start:
logger.warning("Re-starting already-active log context %s", self)
else:
self.usage_start = get_thread_resource_usage()
self.usage_start = rusage
def stop(self) -> None:
if get_thread_id() != self.main_thread:
logger.warning("Stopped logcontext %s on different thread", self)
return
def stop(self, rusage: "Optional[resource._RUsage]") -> None:
"""
Record that this logcontext is no longer running.
# When we stop, let's record the cpu used since we started
if not self.usage_start:
# Log a warning on platforms that support thread usage tracking
if is_thread_resource_usage_supported:
This should not be called directly: use set_current_context
Args:
rusage: the resources used by the current thread, at the point of
switching away from this logcontext. May be None if this platform
doesn't support getrusuage.
"""
try:
if get_thread_id() != self.main_thread:
logger.warning("Stopped logcontext %s on different thread", self)
return
if not rusage:
return
# Record the cpu used since we started
if not self.usage_start:
logger.warning(
"Called stop on logcontext %s without calling start", self
"Called stop on logcontext %s without recording a start rusage",
self,
)
return
return
utime_delta, stime_delta = self._get_cputime()
self._resource_usage.ru_utime += utime_delta
self._resource_usage.ru_stime += stime_delta
utime_delta, stime_delta = self._get_cputime(rusage)
self._resource_usage.ru_utime += utime_delta
self._resource_usage.ru_stime += stime_delta
self.usage_start = None
# if we have a parent, pass our CPU usage stats on
if self.parent_context:
self.parent_context._resource_usage += self._resource_usage
# if we have a parent, pass our CPU usage stats on
if self.parent_context is not None and hasattr(
self.parent_context, "_resource_usage"
):
self.parent_context._resource_usage += self._resource_usage
# reset them in case we get entered again
self._resource_usage.reset()
# reset them in case we get entered again
self._resource_usage.reset()
finally:
self.usage_start = None
def get_resource_usage(self) -> ContextResourceUsage:
"""Get resources used by this logcontext so far.
@ -394,24 +416,24 @@ class LoggingContext(object):
# can include resource usage so far.
is_main_thread = get_thread_id() == self.main_thread
if self.usage_start and is_main_thread:
utime_delta, stime_delta = self._get_cputime()
rusage = get_thread_resource_usage()
assert rusage is not None
utime_delta, stime_delta = self._get_cputime(rusage)
res.ru_utime += utime_delta
res.ru_stime += stime_delta
return res
def _get_cputime(self) -> Tuple[float, float]:
"""Get the cpu usage time so far
def _get_cputime(self, current: "resource._RUsage") -> Tuple[float, float]:
"""Get the cpu usage time between start() and the given rusage
Args:
rusage: the current resource usage
Returns: Tuple[float, float]: seconds in user mode, seconds in system mode
"""
assert self.usage_start is not None
current = get_thread_resource_usage()
# Indicate to mypy that we know that self.usage_start is None.
assert self.usage_start is not None
utime_delta = current.ru_utime - self.usage_start.ru_utime
stime_delta = current.ru_stime - self.usage_start.ru_stime
@ -547,9 +569,11 @@ def set_current_context(context: LoggingContextOrSentinel) -> LoggingContextOrSe
current = current_context()
if current is not context:
current.stop()
rusage = get_thread_resource_usage()
current.stop(rusage)
_thread_local.current_context = context
context.start()
context.start(rusage)
return current