pool

问题 I'm using boost.pool, but I don't know when to use boost::pool<>::malloc and boost::pool<>::ordered_malloc ? so, what's the difference of boost::pool<>::malloc and boost::pool<>::ordered_malloc ? when should I use boost::pool<>::ordered_malloc ? 回答1: First, we should know the basic idea behind the Boost Pool library: simple_segregated_storage , it is similar to a singly linked list, and responsible for partitioning a memory block into fixed-size chunks: A memory pool keeps a free list of

问题 I am a newbie to python,i am have function that calculate feature for my data and then return a list that should be processed and written in file.,..i am using Pool to do the calculation and then and use the callback function to write into file,however the callback function is not being call,i ve put some print statement in it but it is definetly not being called. my code looks like this: def write_arrow_format(results): print("writer called") results[1].to_csv("../data/model_data/feature-"

问题 It cost me a whole night to debug my code, and I finally found this tricky problem. Please take a look at the code below. from multiprocessing import Pool def myfunc(x): return [i for i in range(x)] pool=Pool() A=[] r = pool.map_async(myfunc, (1,2), callback=A.extend) r.wait() I thought I would get A=[0,0,1] , but the output is A=[[0],[0,1]] . This does not make sense to me because if I have A=[] , A.extend([0]) and A.extend([0,1]) will give me A=[0,0,1] . Probably the callback works in a

问题 What would you suggest for Mosquitto connection pooling in Java? We are wasting (blocking) too much time on establishing each connection, so we think some kind of reuse would be better. 回答1: I'd suggest using the generic object pooling in the Apache commons tools https://commons.apache.org/proper/commons-pool/ But also you could extend Thread to instantiate a MQTT connection object on creation and have a persistent connection per thread. This could be combined with the built in thread pool in

问题 What would you suggest for Mosquitto connection pooling in Java? We are wasting (blocking) too much time on establishing each connection, so we think some kind of reuse would be better. 回答1: I'd suggest using the generic object pooling in the Apache commons tools https://commons.apache.org/proper/commons-pool/ But also you could extend Thread to instantiate a MQTT connection object on creation and have a persistent connection per thread. This could be combined with the built in thread pool in

问题 I read sync.Pool design, but find it is two logic, why we need localPool to solve lock compete. We can just use chan to implement one. Using channel is 4x times faster than sync.pool ! Besides pool can clear object, what advantage does it have? This is the pool implementation and benchmarking code: package client import ( "runtime" "sync" "testing" ) type MPool chan interface{} type A struct { s string b int overflow *[2]*[]*string } var p = sync.Pool{ New: func() interface{} { return new(A)

问题 I have been trying to improve my code (with numba and multiprocessing), but I cannot quite get it, because my function has a lot of arguments. I have already simplified it with other functions (see below)... As each agent (a class instance) is independent of each other for these actions, I would like to replace the for with Pool . So I would get a large function pooling() that I would call and pass the list of agents from multiprocessing import Pool p = Pool(4) p.map(pooling, list(agents))

问题 I am creating a particle system in XNA4 and I've bumped into problem. My first particle system was a simple list of particles, whose instances are created when needed. But then I read about using pools. My second system consists of a pool, filled with particles, and an emitter/controller. My pool is pretty basic, this is the code: class Pool<T> where T: new () { public T[] pool; public int nextItem = 0; public Pool(int capacity) { pool = new T[capacity]; for (int i = 0; i < capacity; i++) {

问题 The code below works perfectly on Unix but generates a multiprocessing.TimeoutError on Windows 7 (both OS use python 2.7). Any idea why? Thanks. from multiprocessing import Pool def increment(x): return x + 1 def decrement(x): return x - 1 pool = Pool(processes=2) res1 = pool.map_async(increment, range(10)) res2 = pool.map_async(decrement, range(10)) print res1.get(timeout=1) print res2.get(timeout=1) 回答1: You need to put your actual program logic in side a if __name__ == '__main__': block.

问题 I have a simple python multiprocessing script that sets up a pool of workers that attempt to append work-output to a Manager list. The script has 3 call stacks: - main calls f1 that spawns several worker processes that call another function g1. When one attempts to debug the script (incidentally on Windows 7/64 bit/VS 2010/PyTools) the script runs into a nested process creation loop, spawning an endless number of processes. Can anyone determine why? I'm sure I am missing something very simple