tunning verify mgr cpu number to avoid high workload

tx-pool/src/verify_mgr.rs

@@ -110,9 +110,9 @@ impl VerifyMgr {
         signal_exit: CancellationToken,
     ) -> Self {
         // `num_cpus::get()` will always return at least 1,
-        // minus 1 to avoid high workload on the system
-        // let worker_num = std::cmp::max(num_cpus::get() - 1, 1);
-        let workers: Vec<_> = (0..num_cpus::get())
+        // don't use too many cpu cores to avoid high workload on the system
+        let worker_num = std::cmp::max(num_cpus::get() / 2, 1);
+        let workers: Vec<_> = (0..worker_num)
             .map({
                 let tasks = Arc::clone(&service.verify_queue);
                 let signal_exit = signal_exit.clone();