beremiz

Runtime: work around 1s delay added when using twisted reactor's callLater.
wxPython4
2022-10-05, Edouard Tisserant
c3aae4c95bc1
Runtime: work around 1s delay added when using twisted reactor's callLater.

Since wxPython4, using wxReactor from non-main thread was producing
exceptions in wxWidget's C++ code. Then reactor.run() was called from
main thread, and runtime's worker was delegating calls to reactor
with callLater(0, callable).

While this worked perfectly with wxReactor, it did introduce an unexplained
1 second delay to each worker call when using nomal linux reactors
(i.e. without wxPython). As a workaround reactor runs in a thread when using
twisted without wxPython
#!/usr/bin/env python
# -*- coding: utf-8 -*-
# This file is part of Beremiz
# Copyright (C) 2021: Edouard TISSERANT
#
# See COPYING file for copyrights details.
# Based on Eelco Hoogendoorn stackoverflow answer about RingBuffer with numpy
import numpy as np
class RingBuffer(object):
def __init__(self, width=None, size=131072, padding=None):
self.size = size
self.padding = size if padding is None else padding
shape = (self.size+self.padding,)
if width :
shape += (width,)
self.buffer = np.zeros(shape)
self.cursor = 0
def append(self, data):
"""this is an O(n) operation"""
data = data[-self.size:]
n = len(data)
if self.size + self.padding - self.cursor < n:
self.compact()
self.buffer[self.cursor:][:n] = data
self.cursor += n
@property
def count(self):
return min(self.size, self.cursor)
@property
def view(self):
"""this is always an O(1) operation"""
return self.buffer[max(0, self.cursor - self.size):][:self.count]
def compact(self):
"""
note: only when this function is called, is an O(size) performance hit incurred,
and this cost is amortized over the whole padding space
"""
print 'compacting'
self.buffer[:self.count] = self.view
self.cursor -= self.size