Handy macro to log method execution time

Execution time

declare private function in 'libdispatch':

uint64_t dispatch_benchmark(size_t count, void (^block)(void));

and use it like so:

size_t const objectCount = 1000;
uint64_t n = dispatch_benchmark(10000, ^{
    @autoreleasepool {
        id obj = @42;
        NSMutableArray *array = [NSMutableArray array];
        for (size_t i = 0; i < objectCount; ++i) {
            [array addObject:obj];
        }
    }
});
NSLog(@"-[NSMutableArray addObject:] : %llu ns", n);

Source: 
http://www.objc.io/issue-2/low-level-concurrency-apis.html

-------------------

#define TICK   NSDate *startTime = [NSDate date]
#define TOCK   NSLog(@"Time: %f", -[startTime timeIntervalSinceNow])

Source: http://stackoverflow.com/questions/2129794/how-to-log-a-methods-execution-time-exactly-in-milliseconds