Diagnose system performance issues: CPU/memory usage, disk space, and cleanup. Use when user asks: what's slowing down my computer, why is my Mac slow, what's using CPU/memory/disk, check system performance, find resource hogs, free up space, clean disk, 电脑卡, 查看系统占用, 什么进程占用资源, 磁盘清理, 清理缓存, 磁盘空间不足. Shows process trees and identifies cleanable items.