From cb06335d2d3359e5583cdde10ed73edfeadf6b97 Mon Sep 17 00:00:00 2001 From: Tom Cammann Date: Thu, 3 Jul 2014 11:39:11 +0100 Subject: [PATCH] sync periodic_task fix from incubator Set the value of time the periodic task was last run to a multiple of the spacing value rather than the actual last time run. This ensures tasks runs regularly but avoids synchronizing that interval with other nodes. This patch also removes the coalescing of tasks which are _nearby_ (0.2 seconds away). 4dbd3aa Make periodic tasks run on regular spacing interval 21249f1 Fix parenthesis typo misunderstanding in periodic_task Change-Id: I8873545578f104fd204fbc25493350128b2bc8d4 --- neutron/openstack/common/periodic_task.py | 37 ++++++++++++++++++----- 1 file changed, 30 insertions(+), 7 deletions(-) diff --git a/neutron/openstack/common/periodic_task.py b/neutron/openstack/common/periodic_task.py index 1ebdc1af6..e1f5f78e0 100644 --- a/neutron/openstack/common/periodic_task.py +++ b/neutron/openstack/common/periodic_task.py @@ -11,6 +11,7 @@ # License for the specific language governing permissions and limitations # under the License. +import random import time from oslo.config import cfg @@ -80,14 +81,14 @@ def periodic_task(*args, **kwargs): return f # NOTE(sirp): The `if` is necessary to allow the decorator to be used with - # and without parents. + # and without parenthesis. # - # In the 'with-parents' case (with kwargs present), this function needs to - # return a decorator function since the interpreter will invoke it like: + # In the 'with-parenthesis' case (with kwargs present), this function needs + # to return a decorator function since the interpreter will invoke it like: # # periodic_task(*args, **kwargs)(f) # - # In the 'without-parents' case, the original function will be passed + # In the 'without-parenthesis' case, the original function will be passed # in as the first argument, like: # # periodic_task(f) @@ -142,6 +143,27 @@ class _PeriodicTasksMeta(type): cls._periodic_spacing[name] = task._periodic_spacing +def _nearest_boundary(last_run, spacing): + """Find nearest boundary which is in the past, which is a multiple of the + spacing with the last run as an offset. + + Eg if last run was 10 and spacing was 7, the new last run could be: 17, 24, + 31, 38... + + 0% to 5% of the spacing value will be added to this value to ensure tasks + do not synchronize. This jitter is rounded to the nearest second, this + means that spacings smaller than 20 seconds will not have jitter. + """ + current_time = time.time() + if last_run is None: + return current_time + delta = current_time - last_run + offset = delta % spacing + # Add up to 5% jitter + jitter = int(spacing * (random.random() / 20)) + return current_time - offset + jitter + + @six.add_metaclass(_PeriodicTasksMeta) class PeriodicTasks(object): def __init__(self): @@ -159,17 +181,18 @@ class PeriodicTasks(object): spacing = self._periodic_spacing[task_name] last_run = self._periodic_last_run[task_name] - # If a periodic task is _nearly_ due, then we'll run it early + # Check if due, if not skip idle_for = min(idle_for, spacing) if last_run is not None: delta = last_run + spacing - time.time() - if delta > 0.2: + if delta > 0: idle_for = min(idle_for, delta) continue LOG.debug("Running periodic task %(full_task_name)s", {"full_task_name": full_task_name}) - self._periodic_last_run[task_name] = time.time() + self._periodic_last_run[task_name] = _nearest_boundary( + last_run, spacing) try: task(self, context)