93 lines
2.9 KiB
93 lines
2.9 KiB
// Copyright 2019 The Marl Authors.
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// https://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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// This is an example application that uses Marl to find and print all the prime
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// numbers in the range 1 to 10000000.
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#include "marl/defer.h"
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#include "marl/scheduler.h"
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#include "marl/thread.h"
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#include "marl/ticket.h"
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#include <vector>
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#include <math.h>
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// searchMax defines the upper limit on primes to find.
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constexpr int searchMax = 10000000;
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// searchChunkSize is the number of numbers searched, per task, for primes.
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constexpr int searchChunkSize = 10000;
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// isPrime returns true if i is prime.
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bool isPrime(int i) {
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auto c = static_cast<int>(sqrt(i));
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for (int j = 2; j <= c; j++) {
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if (i % j == 0) {
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return false;
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}
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}
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return true;
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}
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int main() {
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// Create a marl scheduler using the full number of logical cpus.
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// Bind this scheduler to the main thread so we can call marl::schedule()
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marl::Scheduler scheduler(marl::Scheduler::Config::allCores());
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scheduler.bind();
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defer(scheduler.unbind()); // unbind before destructing the scheduler.
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// Create a ticket queue. This will be used to ensure that the primes are
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// printed in ascending order.
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marl::Ticket::Queue queue;
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// Iterate over the range [1, searchMax] in steps of searchChunkSize.
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for (int searchBase = 1; searchBase <= searchMax;
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searchBase += searchChunkSize) {
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// Take a ticket from the ticket queue for this task.
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auto ticket = queue.take();
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// Schedule the task.
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marl::schedule([=] {
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// Find all the primes in [searchBase, searchBase+searchChunkSize-1].
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// Note this is run in parallel with the other scheduled tasks.
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std::vector<int> primes;
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for (int i = searchBase; i < searchBase + searchChunkSize; i++) {
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if (isPrime(i)) {
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primes.push_back(i);
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}
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}
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// Wait until the ticket is called. This ensures that the primes are
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// printed in ascending order. This may cause this task to yield and allow
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// other tasks to be executed while waiting for this ticket to be called.
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ticket.wait();
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// Print the primes.
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for (auto prime : primes) {
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printf("%d is prime\n", prime);
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}
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// Call the next ticket so that those primes can be printed.
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ticket.done();
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});
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}
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// take a ticket and wait on it to ensure that all the primes have been
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// calculated and printed.
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queue.take().wait();
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return 0;
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}
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