Source code for spinn_front_end_common.interface.buffer_management.storage_objects.buffers_sent_deque
# Copyright (c) 2015 The University of Manchester
#
# 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
#
# https://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.
from collections import deque
from threading import Lock
import logging
from spinn_utilities.log import FormatAdapter
from spinnman.messages.eieio.command_messages import (
EventStopRequest, HostSendSequencedData)
from spinn_front_end_common.utilities.exceptions import SpinnFrontEndException
logger = FormatAdapter(logging.getLogger(__name__))
#: The total number of sequence numbers
_N_SEQUENCES = 256
[docs]class BuffersSentDeque(object):
"""
A tracker of buffers sent / to send for a region
"""
__slots__ = [
#: The region being managed
"_region",
#: A queue of messages sent, ordered by sequence number
"_buffers_sent",
#: The current sequence number of the region
"_sequence_number",
#: A lock for the sequence number
"_sequence_lock",
#: The last sequence number to be received on the machine
"_last_received_sequence_number",
#: True if the stop message has been sent
"_sent_stop_message",
#: The number of sequence numbers allowed in a single transmission
"_n_sequences_per_transmission"
]
def __init__(self, region, sent_stop_message=False,
n_sequences_per_tranmission=64):
"""
:param int region: The region being managed
:param bool sent_stop_message: True if the stop message has been sent
:param int n_sequences_per_tranmission:
The number of sequences allowed in each transmission set
"""
self._region = region
self._buffers_sent = deque(maxlen=n_sequences_per_tranmission)
self._sequence_number = 0
self._sequence_lock = Lock()
self._last_received_sequence_number = _N_SEQUENCES - 1
self._sent_stop_message = sent_stop_message
self._n_sequences_per_transmission = n_sequences_per_tranmission
@property
def is_full(self):
"""
Whether the number of messages sent is at the limit for the
sequencing system.
:rtype: bool
"""
return len(self._buffers_sent) >= self._n_sequences_per_transmission
[docs] def is_empty(self):
"""
Determine if there are no messages.
:rtype: int
"""
return len(self._buffers_sent) == 0
[docs] def send_stop_message(self):
"""
Send a message to indicate the end of all the messages.
"""
if not self._sent_stop_message:
self._sent_stop_message = True
self.add_message_to_send(EventStopRequest())
[docs] def add_message_to_send(self, message):
"""
Add a message to send. The message is converted to a sequenced
message.
:param message: The message to be added
:type message:
~spinnman.messages.eieio.abstract_messages.AbstractEIEIOMessage
"""
# If full, raise an exception
if self.is_full:
raise SpinnFrontEndException("The buffer is full")
# Create a sequenced message and update the sequence number
self._sequence_lock.acquire()
sequenced_message = HostSendSequencedData(
self._region, self._sequence_number, message)
self._sequence_number = (self._sequence_number + 1) % _N_SEQUENCES
self._sequence_lock.release()
# Add the sequenced message to the buffers
self._buffers_sent.append(sequenced_message)
@property
def messages(self):
"""
The messages that have been added to the set.
:rtype:
iterable(~spinnman.messages.eieio.command_messages.HostSendSequencedData)
"""
return self._buffers_sent
[docs] def update_last_received_sequence_number(self, last_received_sequence_no):
"""
Updates the last received sequence number. If the sequence number is
within the valid window, packets before the sequence number within the
window are removed, and the last received sequence number is updated,
thus moving the window for the next call. If the sequence number is
not within the valid window, it is assumed to be invalid and so is
ignored.
:param int last_received_sequence_no: The new sequence number
:return: True if update went ahead, False if it was ignored
:rtype: bool
"""
# The sequence number window is between the last received and
# the last received + window size, taking account that the end
# of the window might wrap
min_seq_no_acceptable = self._last_received_sequence_number
max_seq_no_acceptable = (
(min_seq_no_acceptable + self._n_sequences_per_transmission)
% _N_SEQUENCES)
if (min_seq_no_acceptable <= last_received_sequence_no <=
max_seq_no_acceptable):
# The sequence hasn't wrapped and the sequence is valid
self._last_received_sequence_number = last_received_sequence_no
self._remove_messages()
return True
elif max_seq_no_acceptable < min_seq_no_acceptable:
# The sequence has wrapped
if (0 <= last_received_sequence_no <= max_seq_no_acceptable or
min_seq_no_acceptable <= last_received_sequence_no <=
_N_SEQUENCES):
# The sequence is in the valid range
self._last_received_sequence_number = last_received_sequence_no
self._remove_messages()
return True
# If none of the above match, the sequence is out of the window
return False
def _remove_messages(self):
"""
Remove messages that are no longer relevant, based on the last
sequence number received.
"""
min_sequence = (self._last_received_sequence_number -
self._n_sequences_per_transmission)
logger.debug("Removing buffers between {} and {}",
min_sequence, self._last_received_sequence_number)
# If we are at the start of the sequence numbers, keep going back up to
# the allowed window
if min_sequence < 0:
back_min_sequence = min_sequence + _N_SEQUENCES
while (self._buffers_sent and
self._buffers_sent[0].sequence_no > back_min_sequence):
logger.debug("Removing buffer with sequence {}",
self._buffers_sent[0].sequence_no)
self._buffers_sent.popleft()
# Go back through the queue until we reach the last received sequence
while (self._buffers_sent and
min_sequence < self._buffers_sent[0].sequence_no <=
self._last_received_sequence_number):
logger.debug("Removing buffer with sequence {}",
self._buffers_sent[0].sequence_no)
self._buffers_sent.popleft()