Use all cores (#8908)

keygen/src/keygen.rs

@@ -534,13 +534,14 @@ fn do_main(matches: &ArgMatches<'_>) -> Result<(), Box<dyn error::Error>> {
             let start = Instant::now();
             let done = Arc::new(AtomicBool::new(false));
 
-            for _ in 0..num_cpus::get() {
+            let thread_handles: Vec<_> = (0..num_cpus::get())
+                .map(|_| {
                     let done = done.clone();
                     let attempts = attempts.clone();
                     let found = found.clone();
                     let grind_matches_thread_safe = grind_matches_thread_safe.clone();
 
-                let handle = thread::spawn(move || loop {
+                    thread::spawn(move || loop {
                         if done.load(Ordering::Relaxed) {
                             break;
                         }
@@ -579,7 +580,10 @@ fn do_main(matches: &ArgMatches<'_>) -> Result<(), Box<dyn error::Error>> {
                                 grind_matches_thread_safe[i]
                                     .count
                                     .fetch_sub(1, Ordering::Relaxed);
-                            println!("Wrote keypair to {}", &format!("{}.json", keypair.pubkey()));
+                                println!(
+                                    "Wrote keypair to {}",
+                                    &format!("{}.json", keypair.pubkey())
+                                );
                                 write_keypair_file(&keypair, &format!("{}.json", keypair.pubkey()))
                                     .unwrap();
                             }
@@ -587,8 +591,12 @@ fn do_main(matches: &ArgMatches<'_>) -> Result<(), Box<dyn error::Error>> {
                         if total_matches_found == grind_matches_thread_safe.len() {
                             done.store(true, Ordering::Relaxed);
                         }
-                });
+                    })
-                handle.join().unwrap();
+                })
+                .collect();
+
+            for thread_handle in thread_handles {
+                thread_handle.join().unwrap();
             }
         }
         ("verify", Some(matches)) => {