保存核心数据的性能问题

Question

在coredata中保存并获取时我看到了很多CPU使用情况，有什么方法可以进一步优化它，这是我的代码。

import Foundation
import CoreData

import UIKit
class ViewController: UIViewController {
@IBOutlet weak var ButtonSave: UIButton!
@IBOutlet weak var ButtonFetch: UIButton!
@IBOutlet weak var tableView: UITableView!
@IBOutlet weak var ButtonDelete: UIButton!
var queue = OperationQueue()
let appDelegate = UIApplication.shared.delegate as! AppDelegate
var ids: [User] = []
override func viewDidLoad() {
    super.viewDidLoad()

    title = "The List"
    tableView.register(UITableViewCell.self,
                       forCellReuseIdentifier: "Cell")
}

override func didReceiveMemoryWarning() {
    super.didReceiveMemoryWarning()
    // Dispose of any resources that can be recreated.
}


/*
 // MARK: - Navigation

 // In a storyboard-based application, you will often want to do a little preparation before navigation
 override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject?) {
 // Get the new view controller using segue.destinationViewController.
 // Pass the selected object to the new view controller.
 }
 */
@IBAction func ActionSave(_ sender: UIButton) {
    let context = appDelegate.persistentContainer.viewContext
    let entity =
        NSEntityDescription.entity(forEntityName: "User",
                                   in: context)!
    context.mergePolicy =  NSMergeByPropertyObjectTrumpMergePolicy
    for i in 0 ..< 10000
    {

        let person = NSManagedObject(entity: entity,
                                     insertInto: context)
        person.setValue("abcdef", forKeyPath: "name")
        person.setValue(12+i, forKeyPath: "age")
        person.setValue("Male", forKeyPath: "gender")
        person.setValue(i, forKeyPath: "id")

    }
    do {
        try context.save()
    } catch let error as NSError {
        print("Could not save. \(error), \(error.userInfo)")
    }
}
@IBAction func ActionDelete(_ sender: UIButton) {

}

@IBAction func ActionFetch(_ sender: UIButton) {
    let context = appDelegate.persistentContainer.viewContext
    let fetchRequest =
        NSFetchRequest<NSManagedObject>(entityName: "User")
    let sortDescriptor = NSSortDescriptor(key: "id", ascending: true)
    fetchRequest.sortDescriptors = [sortDescriptor]
    do {
        ids = try context.fetch(fetchRequest) as! [User]
        print(ids)
        self.tableView.reloadData()
    } catch let error as NSError {
        print("Could not fetch. \(error), \(error.userInfo)")
    }
}

}
extension ViewController: UITableViewDataSource {

func tableView(_ tableView: UITableView,
               numberOfRowsInSection section: Int) -> Int {
    return ids.count
}

func tableView(_ tableView: UITableView,
               cellForRowAt indexPath: IndexPath)
    -> UITableViewCell {

        let cell =
            tableView.dequeueReusableCell(withIdentifier: "Cell",
                                          for: indexPath)


        let user = self.ids[indexPath.row]
        cell.textLabel?.text = "\(user.id)"
        return cell
}
}