CUDA之nvidia-smi命令详解

nvidia-smi是用来查看GPU使用情况的。我常用这个命令判断哪几块GPU空闲，但是最近的GPU使用状态让我很困惑，于是把nvidia-smi命令显示的GPU使用表中各个内容的具体含义解释一下。

这是服务器上特斯拉K80的信息。
上面的表格中：
第一栏的Fan：N/A是风扇转速，从0到100%之间变动，这个速度是计算机期望的风扇转速，实际情况下如果风扇堵转，可能打不到显示的转速。有的设备不会返回转速，因为它不依赖风扇冷却而是通过其他外设保持低温（比如我们实验室的服务器是常年放在空调房间里的）。
第二栏的Temp：是温度，单位摄氏度。
第三栏的Perf：是性能状态，从P0到P12，P0表示最大性能，P12表示状态最小性能。
第四栏下方的Pwr：是能耗，上方的Persistence-M：是持续模式的状态，持续模式虽然耗能大，但是在新的GPU应用启动时，花费的时间更少，这里显示的是off的状态。
第五栏的Bus-Id是涉及GPU总线的东西，domain:bus:device.function
第六栏的Disp.A是Display Active，表示GPU的显示是否初始化。
第五第六栏下方的Memory Usage是显存使用率。
第七栏是浮动的GPU利用率。
第八栏上方是关于ECC的东西。
第八栏下方Compute M是计算模式。
下面一张表示每个进程占用的显存使用率。

显存占用和GPU占用是两个不一样的东西，显卡是由GPU和显存等组成的，显存和GPU的关系有点类似于内存和CPU的关系。我跑caffe代码的时候显存占得少，GPU占得多，师弟跑TensorFlow代码的时候，显存占得多，GPU占得少。

背景

qgzang@ustc:~$ nvidia-smi -h

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输出如下信息：

NVIDIA System Management Interface – v352.79

NVSMI provides monitoring information for Tesla and select Quadro devices. 
The data is presented in either a plain text or an XML format, via stdout or a file. 
NVSMI also provides several management operations for changing the device state.

Note that the functionality of NVSMI is exposed through the NVML C-based 
library. See the NVIDIA developer website for more information about NVML. 
Python wrappers to NVML are also available. The output of NVSMI is 
not guaranteed to be backwards compatible; NVML and the bindings are backwards 
compatible.

http://developer.nvidia.com/nvidia-management-library-nvml/ 
http://pypi.python.org/pypi/nvidia-ml-py/

Supported products:

• Full Support 
  
  • All Tesla products, starting with the Fermi architecture
  • All Quadro products, starting with the Fermi architecture
  • All GRID products, starting with the Kepler architecture
  • GeForce Titan products, starting with the Kepler architecture
• Limited Support 
  
  • All Geforce products, starting with the Fermi architecture

命令

nvidia-smi [OPTION1 [ARG1]] [OPTION2 [ARG2]] ...

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参数

参数	详解
-h, –help	Print usage information and exit.

LIST OPTIONS:

参数	详解
-L, –list-gpus	Display a list of GPUs connected to the system.

qgzang@ustc:~$ nvidia-smi -L
GPU 0: GeForce GTX TITAN X (UUID: GPU-xxxxx-xxx-xxxxx-xxx-xxxxxx)

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SUMMARY OPTIONS:

参数	详解
-i,–id=	Target a specific GPU.
-f,–filename=	Log to a specified file, rather than to stdout.
-l,–loop=	Probe until Ctrl+C at specified second interval.

QUERY OPTIONS:

参数	详解
-q,	–query
-u,–unit	Show unit, rather than GPU, attributes.
-i,–id=	Target a specific GPU or Unit.
-f,–filename=	Log to a specified file, rather than to stdout.
-x,–xml-format	Produce XML output.
–dtd	When showing xml output, embed DTD.
-d,–display=	Display only selected information: MEMORY,
-l, –loop=	Probe until Ctrl+C at specified second interval.
-lms, –loop-ms=	Probe until Ctrl+C at specified millisecond interval.

SELECTIVE QUERY OPTIONS:

参数	详解	补充
–query-gpu=	Information about GPU.	Call –help-query-gpu for more info.
–query-supported-clocks=	List of supported clocks.	Call –help-query-supported-clocks for more info.
–query-compute-apps=	List of currently active compute processes.	Call –help-query-compute-apps for more info.
–query-accounted-apps=	List of accounted compute processes.	Call –help-query-accounted-apps for more info.
–query-retired-pages=	List of device memory pages that have been retired.	Call –help-query-retired-pages for more info.

[mandatory]

参数	命令
-i, –id=	Target a specific GPU or Unit.
-f, –filename=	Log to a specified file, rather than to stdout.
-l, –loop=	Probe until Ctrl+C at specified second interval.
-lms, –loop-ms=	Probe until Ctrl+C at specified millisecond interval.

DEVICE MODIFICATION OPTIONS:

参数	命令	补充
-pm, –persistence-mode=	Set persistence mode: 0/DISABLED, 1/ENABLED
-e, –ecc-config=	Toggle ECC support: 0/DISABLED, 1/ENABLED
-p, –reset-ecc-errors=	Reset ECC error counts: 0/VOLATILE, 1/AGGREGATE
-c, –compute-mode=	Set MODE for compute applications:	0/DEFAULT,1/EXCLUSIVE_THREAD (deprecated),2/PROHIBITED, 3/EXCLUSIVE_PROCESS
–gom=	Set GPU Operation Mode:	0/ALL_ON, 1/COMPUTE, 2/LOW_DP
-r –gpu-reset	Trigger reset of the GPU.

UNIT MODIFICATION OPTIONS:

参数	命令
-t, –toggle-led=	Set Unit LED state: 0/GREEN, 1/AMBER
-i, –id=	Target a specific Unit.

SHOW DTD OPTIONS:

参数	命令
–dtd	Print device DTD and exit.
-f, –filename=	Log to a specified file, rather than to stdout.
-u, –unit	Show unit, rather than device, DTD.
–debug=	Log encrypted debug information to a specified file.

Process Monitoring:

参数	命令	补充
pmon	Displays process stats in scrolling format.	“nvidia-smi pmon -h” for more information.

TOPOLOGY: (EXPERIMENTAL)

参数	命令	补充
topo	Displays device/system topology. “nvidia-smi topo -h” for more information.	Please see the nvidia-smi(1) manual page for more detailed information.