我有 Debian 8.5 和 gnome 桌面。通常gnome-shellCPU 使用率超过 70%（有时超过 100%）。为什么会发生这种情况？直到现在，当我运行一个python-pygame项目时，gnome-shell 的 CPU 使用率超过 100%，并且游戏运行速度非常慢。
编辑
即使我抓住一个窗口并移动它，这种 CPU 使用率实际上也会发生！即使这样也会导致 gnome-shell 的 CPU 使用率超过 100%。有人可以帮忙吗？
这是一些终端输出：
lspci | grep -i --color vga
00:02.0 VGA compatible controller: Intel Corporation HD Graphics 5500 (rev 09)
lscpu
Architecture: x86_64
CPU op-mode(s): 32-bit, 64-bit
Byte Order: Little Endian
CPU(s): 4
On-line CPU(s) list: 0-3
Thread(s) per core: 2
Core(s) per socket: 2
Socket(s): 1
NUMA node(s): 1
Vendor ID: GenuineIntel
CPU family: 6
Model: 61
Model name: Intel(R) Core(TM) i5-5200U CPU @ 2.20GHz
Stepping: 4
CPU MHz: 2613.359
CPU max MHz: 2700.0000
CPU min MHz: 500.0000
BogoMIPS: 4389.85
Virtualization: VT-x
L1d cache: 32K
L1i cache: 32K
L2 cache: 256K
L3 cache: 3072K
NUMA node0 CPU(s): 0-3
amir@amir-debian:~$ sudo lshw -short
H/W path Device Class Description
=====================================================
system Computer
/0 bus Motherboard
/0/0 memory 7703MiB System memory
/0/1 processor Intel(R) Core(TM) i5-5200U CPU @ 2.20GHz
/0/100 bridge Broadwell-U Host Bridge -OPI
/0/100/2 display HD Graphics 5500
/0/100/3 multimedia Broadwell-U Audio Controller
/0/100/14 bus Wildcat Point-LP USB xHCI Controller
/0/100/14/0 usb3 bus xHCI Host Controller
/0/100/14/1 usb2 bus xHCI Host Controller
/0/100/14/1/5 generic EMV Smartcard Reader
/0/100/14/1/6 generic Generic USB device
/0/100/14/1/7 communication Bluetooth wireless interface
/0/100/14/1/8 multimedia Integrated Camera
/0/100/16 communication Wildcat Point-LP MEI Controller #1
/0/100/19 eth0 network Ethernet Connection (3) I218-LM
/0/100/1b multimedia Wildcat Point-LP High Definition Audio Controller
/0/100/1c bridge Wildcat Point-LP PCI Express Root Port #6
/0/100/1c/0 generic RTS5227 PCI Express Card Reader
/0/100/1c.1 bridge Wildcat Point-LP PCI Express Root Port #3
/0/100/1c.1/0 wlan0 network Wireless 7265
/0/100/1d bus Wildcat Point-LP USB EHCI Controller
/0/100/1d/1 usb1 bus EHCI Host Controller
/0/100/1d/1/1 bus USB hub
/0/100/1f bridge Wildcat Point-LP LPC Controller
/0/100/1f.2 storage Wildcat Point-LP SATA Controller [AHCI Mode]
/0/100/1f.3 bus Wildcat Point-LP SMBus Controller
/0/100/1f.6 generic Wildcat Point-LP Thermal Management Controller
/0/2 scsi0 storage
/0/2/0.0.0 /dev/sda disk 256GB SAMSUNG MZ7LN256
/0/2/0.0.0/1 /dev/sda1 volume 9536MiB EXT4 volume
/0/2/0.0.0/2 /dev/sda2 volume 229GiB Extended partition
/0/2/0.0.0/2/5 /dev/sda5 volume 9346MiB Linux swap / Solaris partition
/0/2/0.0.0/2/6 /dev/sda6 volume 220GiB Linux filesystem partition