Parallel tree algorithms, divide-and-conquer, ... - Challenges: - API: futures? (in Nim “Flowvar” to distinguish from IO-tasks futures) - Synchronization - Scheduling overhead - Thread-safe memory management sleep Memory overhead 24 Task parallelism might generates billions or trillions of tasks and futures - Access from multiple threads: - Heap allocation - Threadsafe allocation/deallocation - Challenges

' ', f2.finished echo "time: ", epochTime() - t0 waitFor f1 # waitFor f1 and f2 # wait for both futures to finish echo f1.finished, ' ', f2.finished echo "total time elapsed: ", epochTime() - t0 false reference that we can use to ask the dispatcher whether our call has been completed or not. But futures can’t get resolved by themselves; we need to actually run the dispatcher in order for any of the result, as we used a Future of void type. We can use the operators and or or to combine multiple futures, in this way we can wait until all of them or at least one of them completes. Note that the dispatcher

' ', f2.finished echo "time: ", epochTime() - t0 waitFor f1 # waitFor f1 and f2 # wait for both futures to finish echo f1.finished, ' ', f2.finished echo "total time elapsed: ", epochTime() - t0 false reference that we can use to ask the dispatcher whether our call has been completed or not. But futures can’t get resolved by themselves; we need to actually run the dispatcher in order for any of the result, as we used a Future of void type. We can use the operators and or or to combine multiple futures, in this way we can wait until all of them or at least one of them completes. Note that the dispatcher

' ', f2.finished echo "time: ", epochTime() - t0 waitFor f1 # waitFor f1 and f2 # wait for both futures to finish echo f1.finished, ' ', f2.finished echo "total time elapsed: ", epochTime() - t0 false reference that we can use to ask the dispatcher whether our call has been completed or not. But futures can’t get resolved by themselves; we need to actually run the dispatcher in order for any of the result, as we used a Future of void type. We can use the operators and or or to combine multiple futures, in this way we can wait until all of them or at least one of them completes. Note that the dispatcher

' ', f2.finished echo "time: ", epochTime() - t0 waitFor f1 # waitFor f1 and f2 # wait for both futures to finish echo f1.finished, ' ', f2.finished echo "total time elapsed: ", epochTime() - t0 false reference that we can use to ask the dispatcher whether our call has been com­ pleted or not. But futures can’t get resolved by themselves; we need to actually run the dispatcher in order for any of the result, as we used a Future of void type. We can use the operators and or or to combine multiple futures, in this way we can wait until all of them or at least one of them completes. Note that the dispatcher

' ', f2.finished echo "time: ", epochTime() - t0 waitFor f1 # waitFor f1 and f2 # wait for both futures to finish echo f1.finished, ' ', f2.finished echo "total time elapsed: ", epochTime() - t0 false reference that we can use to ask the dispatcher whether our call has been completed or not. But futures can’t get resolved by themselves; we need to actually run the dispatcher in order for any of the result, as we used a Future of void type. We can use the operators and or or to combine multiple futures, in this way we can wait until all of them or at least one of them completes. Note that the dispatcher

' ', f2.finished echo "time: ", epochTime() - t0 waitFor f1 # waitFor f1 and f2 # wait for both futures to finish echo f1.finished, ' ', f2.finished echo "total time elapsed: ", epochTime() - t0 false reference that we can use to ask the dispatcher whether our call has been com­ pleted or not. But futures can’t get resolved by themselves; we need to actually run the dispatcher in order for any of the result, as we used a Future of void type. We can use the operators and or or to combine multiple futures, in this way we can wait until all of them or at least one of them completes. Note that the dispatcher

' ', f2.finished echo "time: ", epochTime() - t0 waitFor f1 # waitFor f1 and f2 # wait for both futures to finish echo f1.finished, ' ', f2.finished echo "total time elapsed: ", epochTime() - t0 false reference that we can use to ask the dispatcher whether our call has been com­ pleted or not. But futures can’t get resolved by themselves; we need to actually run the dispatcher in order for any of the result, as we used a Future of void type. We can use the operators and or or to combine multiple futures, in this way we can wait until all of them or at least one of them completes. Note that the dispatcher

' ', f2.finished echo "time: ", epochTime() - t0 waitFor f1 # waitFor f1 and f2 # wait for both futures to finish echo f1.finished, ' ', f2.finished echo "total time elapsed: ", epochTime() - t0 false reference that we can use to ask the dispatcher whether our call has been com­ pleted or not. But futures can’t get resolved by themselves; we need to actually run the dispatcher in order for any of the result, as we used a Future of void type. We can use the operators and or or to combine multiple futures, in this way we can wait until all of them or at least one of them completes. Note that the dispatcher

' ', f2.finished echo "time: ", epochTime() - t0 waitFor f1 # waitFor f1 and f2 # wait for both futures to finish echo f1.finished, ' ', f2.finished echo "total time elapsed: ", epochTime() - t0 false reference that we can use to ask the dispatcher whether our call has been com­ pleted or not. But futures can’t get resolved by themselves; we need to actually run the dispatcher in order for any of the result, as we used a Future of void type. We can use the operators and or or to combine multiple futures, in this way we can wait until all of them or at least one of them completes. Note that the dispatcher