NSOperationQueue Memory Leak
NSOperationQueue Memory Leak
- Subject: NSOperationQueue Memory Leak
- From: Mike Simmons <email@hidden>
- Date: Wed, 06 Aug 2008 08:38:09 -0500
I have an audio application that processes numerous audio streams into
ten-second clips, compresses the clips, and saves them to disk.
Naturally, I wanted to move from single-threaded processing to
multithreaded processing for the clip compression/writing. That was
easily done using the NSOperationQueue and the NSInvocation classes,
and it worked nicely, apart from a bad memory leak that I can't seem
to eradicate. So I finally wrote a small test application to
encapsulate what I was doing in the larger program, and it too has a
leak -- a big one!
The test application simply spawns 10000 threads whose sole job is to
display "Hi, I am thread xx" on the console. It then sleeps and spawns
10000 more. At the end of the run some 38 MB of real memory has been
used, and it never goes down. (I'm not using garbage collection, but
I think I'm doing things correctly with the autorelease pool.)
Can someone tell me what I'm doing wrong?
Thanks!
Mike
---------------------------------------------------------------------------------------------------
#import <Foundation/Foundation.h>
@interface OperationQueueTester : NSObject
{
}
- (void) run;
- (void) sayHi:(id)blah;
- (void) queueOperations:(int) count;
@end
@implementation OperationQueueTester
- (id) init
{
return self;
}
- (void) run
{
// Allow a bit of time to have a look at the initial memory usage.
NSLog(@"Starting in 5 seconds...");
sleep(5);
// Throw a bunch of simple operations into the operation queue.
[self queueOperations:10000];
sleep(10);
[self queueOperations:10000];
// Allow a bit of time to look at the final memory usage.
NSLog(@"All threads have finished processing.");
sleep(3600);
}
- (void) queueOperations:(int) count
{
NSAutoreleasePool *pool = [[NSAutoreleasePool alloc] init];
NSInvocationOperation *processor;
NSOperationQueue *operationQueue = [[[NSOperationQueue alloc] init]
autorelease];
NSLog(@"Preparing to queue operations");
// Add multiple "process:" operations to the queue with no argument.
for (int i = 0; i < count; i++)
{
processor = [[NSInvocationOperation alloc] initWithTarget:self
selector:@selector(sayHi:) object:nil];
[operationQueue addOperation:processor];
}
NSLog(@"All threads queued.");
[operationQueue waitUntilAllOperationsAreFinished];
[pool release];
}
- (void) sayHi:(id)blah
{
static int counter = 0;
NSLog(@"Hi. I am thread %d", counter++);
}
@end
/**
Main routine, in which an object is instantiated to queue a large
number of operations into an operation queue.
**/
int main (int argc, const char * argv[])
{
NSAutoreleasePool * pool = [[NSAutoreleasePool alloc] init];
OperationQueueTester *queueTester = [[OperationQueueTester alloc]
init];
[queueTester run];
[pool drain];
return 0;
}
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