pool

Here's the program: #!/usr/bin/python import multiprocessing def dummy_func(r): pass def worker(): pass if __name__ == '__main__': pool = multiprocessing.Pool(processes=16) for index in range(0,100000): pool.apply_async(worker, callback=dummy_func) # clean up pool.close() pool.join() I found memory usage (both VIRT and RES) kept growing up till close()/join(), is there any solution to get rid of this? I tried maxtasksperchild with 2.7 but it didn't help either. I have a more complicated program that calles apply_async() ~6M times, and at ~1.5M point I've already got 6G+ RES, to avoid all other

I'm applying some parallelization to my code, in which I use classes. I knew that is not possible to pick a class method without any other approach different of what Python provides. I found a solution here . In my code, I have to parts that should be parallelized, both using class. Here, I'm posting a very simple code just representing the structure of mine (is the same, but I deleted the methods content, which was a lot of math calculus, insignificant for the output that I'm getting). The problem is 'cause I can pickle one method (shepard_interpolation), but with the other one (calculate

I am trying to create a copy of a CMSampleBuffer as returned by captureOutput in a AVCaptureVideoDataOutputSampleBufferDelegate. Since the CMSampleBuffers come from a preallocated pool of (15) buffers, if I attach a reference to them they cannot be recollected. This causes all remaining frames to be dropped. To maintain optimal performance, some sample buffers directly reference pools of memory that may need to be reused by the device system and other capture inputs. This is frequently the case for uncompressed device native capture where memory blocks are copied as little as possible. If

Instead of just using urllib does anyone know of the most efficient package for fast, multithreaded downloading of URLs that can operate through http proxies? I know of a few such as Twisted, Scrapy, libcurl etc. but I don't know enough about them to make a decision or even if they can use proxies.. Anyone know of the best one for my purposes? Thanks! is's simple to implement this in python. The urlopen() function works transparently with proxies which do not require authentication. In a Unix or Windows environment, set the http_proxy, ftp_proxy or gopher_proxy environment variables to a URL

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 different way. So my question is how to get A=[0,0,1] instead of [[0],[0,1]] ? Thank you in advance for

I want to fill a 2D-numpy array within a for loop and fasten the calculation by using multiprocessing. import numpy from multiprocessing import Pool array_2D = numpy.zeros((20,10)) pool = Pool(processes = 4) def fill_array(start_val): return range(start_val,start_val+10) list_start_vals = range(40,60) for line in xrange(20): array_2D[line,:] = pool.map(fill_array,list_start_vals) pool.close() print array_2D The effect of executing it is that Python runs 4 subprocesses and occupies 4 CPU cores BUT the execution doesn´t finish and the array is not printed. If I try to write the array to the disk

Is there are way to access the contents of the String constant pool within our own program? Say I have some basic code that does this: String str1 = "foo"; String str2 = "bar"; There are now 2 strings floating around in our String constant pool. Is there some way to access the pool and print out the above values or get the current total number of elements currently contained in the pool? i.e. StringConstantPool pool = new StringConstantPool(); System.out.println(pool.getSize()); // etc You cannot directly access the String intern pool . As per Javadocs String intern pool is: A pool of strings,