Why is my CUDA GPU-Util ~70% when there are "No running processes found"?

Question

After configuring a system with 2 Tesla K80 cards, I noticed when running nvidia-smi that one of the 4 GPUs was under heavy load despite there being "No running processes found". Why is this happening and how do I correct this?

Here is the output from nvidia-smi:

➜  compute-0-1: ~/> nvidia-smi
Mon Sep 26 14:48:00 2016       
+-----------------------------------------------------------------------------+
| NVIDIA-SMI 361.77                 Driver Version: 361.77                    |
|-------------------------------+----------------------+----------------------+
| GPU  Name        Persistence-M| Bus-Id        Disp.A | Volatile Uncorr. ECC |
| Fan  Temp  Perf  Pwr:Usage/Cap|         Memory-Usage | GPU-Util  Compute M. |
|===============================+======================+======================|
|   0  Tesla K80           Off  | 0000:05:00.0     Off |                    0 |
| N/A   34C    P0    57W / 149W |      0MiB / 11441MiB |      0%      Default |
+-------------------------------+----------------------+----------------------+
|   1  Tesla K80           Off  | 0000:06:00.0     Off |                    0 |
| N/A   26C    P0    76W / 149W |      0MiB / 11441MiB |      0%      Default |
+-------------------------------+----------------------+----------------------+
|   2  Tesla K80           Off  | 0000:85:00.0     Off |                    0 |
| N/A   33C    P0    60W / 149W |      0MiB / 11441MiB |      0%      Default |
+-------------------------------+----------------------+----------------------+
|   3  Tesla K80           Off  | 0000:86:00.0     Off |                    0 |
| N/A   24C    P0    74W / 149W |      0MiB / 11441MiB |     71%      Default |
+-------------------------------+----------------------+----------------------+

+-----------------------------------------------------------------------------+
| Processes:                                                       GPU Memory |
|  GPU       PID  Type  Process name                               Usage      |
|=============================================================================|
|  No running processes found                                                 |
+-----------------------------------------------------------------------------+

score 5 · Answer 1 · answered Sep 26 '16 at 18:57

This nvidia forum addresses the issue. To correct this, enabling Persistence Mode:

sudo nvidia-smi -pm 1

After running this command, here are the nvidia-smi results:

➜  compute-0-1: ~/> nvidia-smi            Mon Sep 26 14:55:21 2016    
Mon Sep 26 14:55:21 2016       
+-----------------------------------------------------------------------------+
| NVIDIA-SMI 361.77                 Driver Version: 361.77                    |
|-------------------------------+----------------------+----------------------+
| GPU  Name        Persistence-M| Bus-Id        Disp.A | Volatile Uncorr. ECC |
| Fan  Temp  Perf  Pwr:Usage/Cap|         Memory-Usage | GPU-Util  Compute M. |
|===============================+======================+======================|
|   0  Tesla K80           On   | 0000:05:00.0     Off |                    0 |
| N/A   36C    P8    27W / 149W |      0MiB / 11441MiB |      0%      Default |
+-------------------------------+----------------------+----------------------+
|   1  Tesla K80           On   | 0000:06:00.0     Off |                    0 |
| N/A   28C    P8    30W / 149W |      0MiB / 11441MiB |      0%      Default |
+-------------------------------+----------------------+----------------------+
|   2  Tesla K80           On   | 0000:85:00.0     Off |                    0 |
| N/A   37C    P8    28W / 149W |      0MiB / 11441MiB |      0%      Default |
+-------------------------------+----------------------+----------------------+
|   3  Tesla K80           On   | 0000:86:00.0     Off |                    0 |
| N/A   27C    P8    72W / 149W |      0MiB / 11441MiB |      0%      Default |
+-------------------------------+----------------------+----------------------+

+-----------------------------------------------------------------------------+
| Processes:                                                       GPU Memory |
|  GPU       PID  Type  Process name                               Usage      |
|=============================================================================|
|  No running processes found                                                 |
+-----------------------------------------------------------------------------+

Enabling persistence mode has the above effect at the expense of additional power consumption when the GPUs are at idle. — , Sep 26 '16 at 19:24
@RobertCrovella, looking at the power usage after turning on persistence mode, the consumption appears to have gone down, at least at the moment reported, though the biggest change is for the 3 GPUs that were idle. Is this decrease just a instantaneous measure, i.e., over time the consumption will be higher? Thanks for the input. — Steven C. Howell, Sep 27 '16 at 14:33

Why is my CUDA GPU-Util ~70% when there are "No running processes found"?

1 Answers1