454

I have installed tensorflow in my ubuntu 16.04 using the second answer here with ubuntu's builtin apt cuda installation.

Now my question is how can I test if tensorflow is really using gpu? I have a gtx 960m gpu. When I import tensorflow this is the output

I tensorflow/stream_executor/dso_loader.cc:105] successfully opened CUDA library libcublas.so locally I tensorflow/stream_executor/dso_loader.cc:105] successfully opened CUDA library libcudnn.so locally I tensorflow/stream_executor/dso_loader.cc:105] successfully opened CUDA library libcufft.so locally I tensorflow/stream_executor/dso_loader.cc:105] successfully opened CUDA library libcuda.so.1 locally I tensorflow/stream_executor/dso_loader.cc:105] successfully opened CUDA library libcurand.so locally 

Is this output enough to check if tensorflow is using gpu ?

8
  • 2
    You should see something like this in your log: I tensorflow/core/common_runtime/gpu/gpu_device.cc:838] Creating TensorFlow device (/gpu:0) -> (device: 0, name: GeForce GTX 980, pci bus id: 0000:03:00.0) Commented Jun 24, 2016 at 23:32
  • 3
    There's log_device_placement approach in answer. The most reliable way is to look at timeline as specified in this comment: github.com/tensorflow/tensorflow/issues/… Commented Jun 24, 2016 at 23:33
  • Yes , I have got this output following Yao Zhang's answer... Commented Jun 25, 2016 at 5:39
  • 1
    It writes to stdout or stderr Commented Oct 14, 2016 at 19:11
  • 6
    tf.config.list_physical_devices('GPU') Commented Feb 20, 2021 at 3:17

32 Answers 32

459

No, I don't think "open CUDA library" is enough to tell, because different nodes of the graph may be on different devices.

When using tensorflow2:

print("Num GPUs Available: ", len(tf.config.list_physical_devices('GPU'))) 

For tensorflow1, to find out which device is used, you can enable log device placement like this:

sess = tf.Session(config=tf.ConfigProto(log_device_placement=True)) 

Check your console for this type of output.

Sign up to request clarification or add additional context in comments.

15 Comments

I tried this and it prints absolutely nothing. Any idea why that might be?
Did you do it on a jupyter notebook ?
The output may be produced on the console from where you ran the Jupyter Notebook.
Can we get an updated answer for Tensorflow V2 (where tf.Sessions are not supported).
@iyop45 For tensorflow V2, the command is a bit modified: sess = tf.compat.v1.Session(config=tf.compat.v1.ConfigProto(log_device_placement=True))
|
302

Apart from using sess = tf.Session(config=tf.ConfigProto(log_device_placement=True)) which is outlined in other answers as well as in the official TensorFlow documentation, you can try to assign a computation to the gpu and see whether you have an error.

import tensorflow as tf with tf.device('/gpu:0'): a = tf.constant([1.0, 2.0, 3.0, 4.0, 5.0, 6.0], shape=[2, 3], name='a') b = tf.constant([1.0, 2.0, 3.0, 4.0, 5.0, 6.0], shape=[3, 2], name='b') c = tf.matmul(a, b) with tf.Session() as sess: print (sess.run(c)) 

Here

  • "/cpu:0": The CPU of your machine.
  • "/gpu:0": The GPU of your machine, if you have one.

If you have a gpu and can use it, you will see the result. Otherwise you will see an error with a long stacktrace. In the end you will have something like this:

Cannot assign a device to node 'MatMul': Could not satisfy explicit device specification '/device:GPU:0' because no devices matching that specification are registered in this process


Recently a few helpful functions appeared in TF:

You can also check for available devices in the session:

with tf.Session() as sess: devices = sess.list_devices() 

devices will return you something like

[_DeviceAttributes(/job:tpu_worker/replica:0/task:0/device:CPU:0, CPU, -1, 4670268618893924978), _DeviceAttributes(/job:tpu_worker/replica:0/task:0/device:XLA_CPU:0, XLA_CPU, 17179869184, 6127825144471676437), _DeviceAttributes(/job:tpu_worker/replica:0/task:0/device:XLA_GPU:0, XLA_GPU, 17179869184, 16148453971365832732), _DeviceAttributes(/job:tpu_worker/replica:0/task:0/device:TPU:0, TPU, 17179869184, 10003582050679337480), _DeviceAttributes(/job:tpu_worker/replica:0/task:0/device:TPU:1, TPU, 17179869184, 5678397037036584928) 

11 Comments

Result:[[ 22. 28.] [ 49. 64.]]
@GeorgePligor the result is not really important here. Either you have a result and the GPU was used or you have an error, which means that it was not used
This did not work for me. I ran this inside of my Docker Container that is exectued by the nvidia-docker and etcetc. However I get no error and the CPU is the one that does the work. I upped the matrices a bit (10k*10k) to ensure it calculates for a while. CPU util went up to 100% but the GPU stayed cool as always.
I got the "no devices matching" error when run it in console. In IDE like pycharm there is no error. I guess it's related to the Session I used, which is different in console.
dosen't seem to work for tensorflow 2.1 at all, even after replacing Session with tf.compat.v1.Session()
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208

Following piece of code should give you all devices available to tensorflow.

from tensorflow.python.client import device_lib print(device_lib.list_local_devices()) 

Sample Output

[name: "/cpu:0" device_type: "CPU" memory_limit: 268435456 locality { } incarnation: 4402277519343584096,

name: "/gpu:0" device_type: "GPU" memory_limit: 6772842168 locality { bus_id: 1 } incarnation: 7471795903849088328 physical_device_desc: "device: 0, name: GeForce GTX 1070, pci bus id: 0000:05:00.0" ]

4 Comments

and if this command does not return any entry with "GPU", does it mean my machine simply does have GPU, or tensorflow is not able to locate it?
@mercury0114 it may be either. for example, you may have a gpu but not have tensorflow-gpu properly installed.
I disagree, this does not answer the question: it's not about devices available but devises used. And that can be an entirely different story! (e.g. TF will only use 1 GPU by default.
name: "/device:GPU:0" device_type: "GPU" memory_limit: 10711446324 locality { bus_id: 1 links { }} incarnation: 17935632445266485019 physical_device_desc: "device: 0, name: GeForce RTX 2080 Ti, pci bus id: 0000:01:00.0, compute capability: 7.5"]
140

Tensorflow 2.0

Sessions are no longer used in 2.0. Instead, one can use tf.test.is_gpu_available:

import tensorflow as tf assert tf.test.is_gpu_available() assert tf.test.is_built_with_cuda() 

If you get an error, you need to check your installation.

4 Comments

That also works with TF 1.14 (maybe even a few older versions)!
It is now recommended to do tf.config.list_physical_devices('GPU')
@Roy Shilkrot I think 'tf.config.list_physical_devices('GPU')' doesn't work in Tensorflow 2.0
@joselquin The TF v2.x docs state it should work: tensorflow.org/api_docs/python/tf/config/experimental/… , and I can verify it does work for me.
124

I think there is an easier way to achieve this.

import tensorflow as tf if tf.test.gpu_device_name(): print('Default GPU Device: {}'.format(tf.test.gpu_device_name())) else: print("Please install GPU version of TF") 

It usually prints like

Default GPU Device: /device:GPU:0 

This seems easier to me rather than those verbose logs.

Edit:- This was tested for TF 1.x versions. I never had a chance to do stuff with TF 2.0 or above so keep in mind.

3 Comments

Agreed. Easier than the approaches described above. Prints the list of GPUs its using. Thanks
This isn't a valid test. It will return into the else statement even if you have the GPU version of tensorflow installed.
Works for me of tf-1.14 and two GPU inside.
40

UPDATE FOR TENSORFLOW >= 2.1

The recommended way in which to check if TensorFlow is using GPU is the following:

tf.config.list_physical_devices('GPU') 

As of TensorFlow 2.1, tf.test.gpu_device_name() has been deprecated in favour of the aforementioned.

Then, in the terminal you can use nvidia-smi to check how much GPU memory has been alloted; at the same time, using watch -n K nvidia-smi would tell you for example every K seconds how much memory you are using (you may want to use K = 1 for real-time)

If you have multiple GPUs and you want to use multiple networks, each one on a separated GPU, you can use:

 with tf.device('/GPU:0'): neural_network_1 = initialize_network_1() with tf.device('/GPU:1'): neural_network_2 = initialize_network_2() 

1 Comment

To see constantly how much GPU memory using , use nvidia-smi -l 10.
32

Ok, first launch an ipython shell from the terminal and import TensorFlow:

$ ipython --pylab Python 3.6.5 |Anaconda custom (64-bit)| (default, Apr 29 2018, 16:14:56) Type 'copyright', 'credits' or 'license' for more information IPython 6.4.0 -- An enhanced Interactive Python. Type '?' for help. Using matplotlib backend: Qt5Agg In [1]: import tensorflow as tf 

Now, we can watch the GPU memory usage in a console using the following command:

# realtime update for every 2s $ watch -n 2 nvidia-smi 

Since we've only imported TensorFlow but have not used any GPU yet, the usage stats will be:

tf non-gpu usage

Notice how the GPU memory usage is very less (~ 700MB); Sometimes the GPU memory usage might even be as low as 0 MB.


Now, let's load the GPU in our code. As indicated in tf documentation, do:

In [2]: sess = tf.Session(config=tf.ConfigProto(log_device_placement=True)) 

Now, the watch stats should show an updated GPU usage memory as below:

tf gpu-watch

Observe now how our Python process from the ipython shell is using ~ 7 GB of the GPU memory.


P.S. You can continue watching these stats as the code is running, to see how intense the GPU usage is over time.

Comments

30

This will confirm that tensorflow using GPU while training also ?

Code

sess = tf.Session(config=tf.ConfigProto(log_device_placement=True)) 

Output

I tensorflow/core/common_runtime/gpu/gpu_device.cc:885] Found device 0 with properties: name: GeForce GT 730 major: 3 minor: 5 memoryClockRate (GHz) 0.9015 pciBusID 0000:01:00.0 Total memory: 1.98GiB Free memory: 1.72GiB I tensorflow/core/common_runtime/gpu/gpu_device.cc:906] DMA: 0 I tensorflow/core/common_runtime/gpu/gpu_device.cc:916] 0: Y I tensorflow/core/common_runtime/gpu/gpu_device.cc:975] Creating TensorFlow device (/gpu:0) -> (device: 0, name: GeForce GT 730, pci bus id: 0000:01:00.0) Device mapping: /job:localhost/replica:0/task:0/gpu:0 -> device: 0, name: GeForce GT 730, pci bus id: 0000:01:00.0 I tensorflow/core/common_runtime/direct_session.cc:255] Device mapping: /job:localhost/replica:0/task:0/gpu:0 -> device: 0, name: GeForce GT 730, pci bus id: 0000:01:00.0 

1 Comment

Please add a little explanation to why your answer is working (what does the log_device_placement do and how to see CPU vs. GPU in the output?). That will improve the quality of your answer!
30

In addition to other answers, the following should help you to make sure that your version of tensorflow includes GPU support.

import tensorflow as tf print(tf.test.is_built_with_cuda()) 

1 Comment

Warning: That tells you if TensorFlow is compiled with GPU. Not whether the GPU is being used. (If the drivers are not installed properly for example, then the CPU is used, even if "is_built_with_cuda()" is true.)
19

This should give the list of devices available for Tensorflow (under Py-3.6):

tf = tf.Session(config=tf.ConfigProto(log_device_placement=True)) tf.list_devices() # _DeviceAttributes(/job:localhost/replica:0/task:0/device:CPU:0, CPU, 268435456) 

Comments

14

I prefer to use nvidia-smi to monitor GPU usage. if it goes up significantly when you start you program, it's a strong sign that your tensorflow is using GPU.

5 Comments

This is an indirect way
How do you use nvdia-smi to monitor GPU usage?
after you install cuda. nvidia-smi should be in your system. I usually use 'nvidia-smi -l ' to monitor the usage.
You can also use watch nvidia-smi, updates the screen every 2 seconds
watch nvidia-smi works well for me. I can also see in the output that my python process is using the GPU
9

I find just querying the gpu from the command line is easiest:

nvidia-smi +-----------------------------------------------------------------------------+ | NVIDIA-SMI 384.98 Driver Version: 384.98 | |-------------------------------+----------------------+----------------------+ | GPU Name Persistence-M| Bus-Id Disp.A | Volatile Uncorr. ECC | | Fan Temp Perf Pwr:Usage/Cap| Memory-Usage | GPU-Util Compute M. | |===============================+======================+======================| | 0 GeForce GTX 980 Ti Off | 00000000:02:00.0 On | N/A | | 22% 33C P8 13W / 250W | 5817MiB / 6075MiB | 0% Default | +-------------------------------+----------------------+----------------------+ +-----------------------------------------------------------------------------+ | Processes: GPU Memory | | GPU PID Type Process name Usage | |=============================================================================| | 0 1060 G /usr/lib/xorg/Xorg 53MiB | | 0 25177 C python 5751MiB | +-----------------------------------------------------------------------------+ 

if your learning is a background process the pid from jobs -p should match the pid from nvidia-smi

Comments

9

With the recent updates of Tensorflow, you can check it as follow :

tf.test.is_gpu_available( cuda_only=False, min_cuda_compute_capability=None) 

This will return True if GPU is being used by Tensorflow, and return False otherwise.

If you want device device_name you can type : tf.test.gpu_device_name(). Get more details from here

Comments

9

With tensorflow 2.0 >=

import tensorflow as tf sess = tf.compat.v1.Session(config=tf.compat.v1.ConfigProto(log_device_placement=True)) 

enter image description here

Comments

8

Run the following in Jupyter,

import tensorflow as tf sess = tf.Session(config=tf.ConfigProto(log_device_placement=True)) 

If you've set up your environment properly, you'll get the following output in the terminal where you ran "jupyter notebook",

2017-10-05 14:51:46.335323: I c:\tf_jenkins\home\workspace\release-win\m\windows-gpu\py\35\tensorflow\core\common_runtime\gpu\gpu_device.cc:1030] Creating TensorFlow device (/gpu:0) -> (device: 0, name: Quadro K620, pci bus id: 0000:02:00.0) Device mapping: /job:localhost/replica:0/task:0/gpu:0 -> device: 0, name: Quadro K620, pci bus id: 0000:02:00.0 2017-10-05 14:51:46.337418: I c:\tf_jenkins\home\workspace\release-win\m\windows-gpu\py\35\tensorflow\core\common_runtime\direct_session.cc:265] Device mapping: /job:localhost/replica:0/task:0/gpu:0 -> device: 0, name: Quadro K620, pci bus id: 0000:02:00.0 

You can see here I'm using TensorFlow with an Nvidia Quodro K620.

2 Comments

Jupyter is not necessary at all, please don't add complexity to the question
Some users may want to ensure GPU is usable in Jupyter. Additionally, this can be run from a Python script.
8

For TF2.4+ listed as the "official" way on tensorflow website to check if TF is using GPU or Not

>>> import tensorflow as tf >>> print("Num GPUs Available: ", len(tf.config.experimental.list_physical_devices('GPU'))) Num GPUs Available: 2 

Comments

6

You can check if you are currently using the GPU by running the following code:

import tensorflow as tf tf.test.gpu_device_name() 

If the output is '', it means you are using CPU only;
If the output is something like that /device:GPU:0, it means GPU works.


And use the following code to check which GPU you are using:

from tensorflow.python.client import device_lib device_lib.list_local_devices() 

2 Comments

If the output is ' ', then what should we do?
@Jason Just reinstall a GPU version.
6

I found below snippet is very handy to test the gpu ..

Tensorflow 2.0 Test

import tensorflow as tf import tensorflow.compat.v1 as tf tf.disable_v2_behavior() with tf.device('/gpu:0'): a = tf.constant([1.0, 2.0, 3.0, 4.0, 5.0, 6.0], shape=[2, 3], name='a') b = tf.constant([1.0, 2.0, 3.0, 4.0, 5.0, 6.0], shape=[3, 2], name='b') c = tf.matmul(a, b) with tf.Session() as sess: print (sess.run(c)) 

Tensorflow 1 Test

import tensorflow as tf with tf.device('/gpu:0'): a = tf.constant([1.0, 2.0, 3.0, 4.0, 5.0, 6.0], shape=[2, 3], name='a') b = tf.constant([1.0, 2.0, 3.0, 4.0, 5.0, 6.0], shape=[3, 2], name='b') c = tf.matmul(a, b) with tf.Session() as sess: print (sess.run(c)) 

Comments

6

Put this near the top of your jupyter notebook. Comment out what you don't need.

# confirm TensorFlow sees the GPU from tensorflow.python.client import device_lib assert 'GPU' in str(device_lib.list_local_devices()) # confirm Keras sees the GPU (for TensorFlow 1.X + Keras) from keras import backend assert len(backend.tensorflow_backend._get_available_gpus()) > 0 # confirm PyTorch sees the GPU from torch import cuda assert cuda.is_available() assert cuda.device_count() > 0 print(cuda.get_device_name(cuda.current_device())) 

NOTE: With the release of TensorFlow 2.0, Keras is now included as part of the TF API.

Originally answerwed here.

Comments

6
>>> import tensorflow as tf >>> tf.config.list_physical_devices('GPU') 2020-05-10 14:58:16.243814: I tensorflow/stream_executor/platform/default/dso_loader.cc:44] Successfully opened dynamic library libcuda.so.1 2020-05-10 14:58:16.262675: I tensorflow/stream_executor/cuda/cuda_gpu_executor.cc:981] successful NUMA node read from SysFS had negative value (-1), but there must be at least one NUMA node, so returning NUMA node zero 2020-05-10 14:58:16.263119: I tensorflow/core/common_runtime/gpu/gpu_device.cc:1555] Found device 0 with properties: pciBusID: 0000:01:00.0 name: GeForce GTX 1060 6GB computeCapability: 6.1 coreClock: 1.7715GHz coreCount: 10 deviceMemorySize: 5.93GiB deviceMemoryBandwidth: 178.99GiB/s 2020-05-10 14:58:16.263143: I tensorflow/stream_executor/platform/default/dso_loader.cc:44] Successfully opened dynamic library libcudart.so.10.1 2020-05-10 14:58:16.263188: I tensorflow/stream_executor/platform/default/dso_loader.cc:44] Successfully opened dynamic library libcublas.so.10 2020-05-10 14:58:16.264289: I tensorflow/stream_executor/platform/default/dso_loader.cc:44] Successfully opened dynamic library libcufft.so.10 2020-05-10 14:58:16.264495: I tensorflow/stream_executor/platform/default/dso_loader.cc:44] Successfully opened dynamic library libcurand.so.10 2020-05-10 14:58:16.265644: I tensorflow/stream_executor/platform/default/dso_loader.cc:44] Successfully opened dynamic library libcusolver.so.10 2020-05-10 14:58:16.266329: I tensorflow/stream_executor/platform/default/dso_loader.cc:44] Successfully opened dynamic library libcusparse.so.10 2020-05-10 14:58:16.266357: I tensorflow/stream_executor/platform/default/dso_loader.cc:44] Successfully opened dynamic library libcudnn.so.7 2020-05-10 14:58:16.266478: I tensorflow/stream_executor/cuda/cuda_gpu_executor.cc:981] successful NUMA node read from SysFS had negative value (-1), but there must be at least one NUMA node, so returning NUMA node zero 2020-05-10 14:58:16.266823: I tensorflow/stream_executor/cuda/cuda_gpu_executor.cc:981] successful NUMA node read from SysFS had negative value (-1), but there must be at least one NUMA node, so returning NUMA node zero 2020-05-10 14:58:16.267107: I tensorflow/core/common_runtime/gpu/gpu_device.cc:1697] Adding visible gpu devices: 0 [PhysicalDevice(name='/physical_device:GPU:0', device_type='GPU')] 

As suggested by @AmitaiIrron:

This section indicates that a gpu was found

2020-05-10 14:58:16.263119: I tensorflow/core/common_runtime/gpu/gpu_device.cc:1555] Found device 0 with properties: pciBusID: 0000:01:00.0 name: GeForce GTX 1060 6GB computeCapability: 6.1 coreClock: 1.7715GHz coreCount: 10 deviceMemorySize: 5.93GiB deviceMemoryBandwidth: 178.99GiB/s 

And here that it got added as an available physical device

2020-05-10 14:58:16.267107: I tensorflow/core/common_runtime/gpu/gpu_device.cc:1697] Adding visible gpu devices: 0 [PhysicalDevice(name='/physical_device:GPU:0', device_type='GPU')] 

2 Comments

It would be useful if you point to the sections in the output that indicate whether a GPU is used.
@AmitaiIrron Thanks for the suggestion, i hope it is a bit more clear now.
6

In the new versions of TF(>2.1) the recommended way for checking whether TF is using GPU is:

tf.config.list_physical_devices('GPU') 

Comments

5

For Tensorflow 2.0

import tensorflow as tf tf.test.is_gpu_available( cuda_only=False, min_cuda_compute_capability=None ) 

source here

other option is:

tf.config.experimental.list_physical_devices('GPU') 

1 Comment

is_gpu_available (from tensorflow.python.framework.test_util) is deprecated and will be removed in a future version.
5

The following will also return the name of your GPU devices.

import tensorflow as tf tf.test.gpu_device_name() 

1 Comment

If the output of this command is an empty string ... how I do debug?
5

Tensorflow 2.1

A simple calculation that can be verified with nvidia-smi for memory usage on the GPU.

import tensorflow as tf c1 = [] n = 10 def matpow(M, n): if n < 1: #Abstract cases where n < 1 return M else: return tf.matmul(M, matpow(M, n-1)) with tf.device('/gpu:0'): a = tf.Variable(tf.random.uniform(shape=(10000, 10000)), name="a") b = tf.Variable(tf.random.uniform(shape=(10000, 10000)), name="b") c1.append(matpow(a, n)) c1.append(matpow(b, n)) 

1 Comment

A nice test not only to check if tensorflow sees the GPU but if it will actually use one.
4

Run this command in Jupyter or your IDE to check if Tensorflow is using a GPU or not: tf.config.list_physical_devices('GPU')

Comments

3

This is the line I am using to list devices available to tf.session directly from bash:

python -c "import os; os.environ['TF_CPP_MIN_LOG_LEVEL'] = '3'; import tensorflow as tf; sess = tf.Session(); [print(x) for x in sess.list_devices()]; print(tf.__version__);" 

It will print available devices and tensorflow version, for example:

_DeviceAttributes(/job:localhost/replica:0/task:0/device:CPU:0, CPU, 268435456, 10588614393916958794) _DeviceAttributes(/job:localhost/replica:0/task:0/device:XLA_GPU:0, XLA_GPU, 17179869184, 12320120782636586575) _DeviceAttributes(/job:localhost/replica:0/task:0/device:XLA_CPU:0, XLA_CPU, 17179869184, 13378821206986992411) _DeviceAttributes(/job:localhost/replica:0/task:0/device:GPU:0, GPU, 32039954023, 12481654498215526877) 1.14.0 

Comments

3

You have some options to test whether GPU acceleration is being used by your TensorFlow installation.

You can type in the following commands in three different platforms.

import tensorflow as tf sess = tf.Session(config=tf.ConfigProto(log_device_placement=True)) 
  1. Jupyter Notebook - Check the console which is running the Jupyter Notebook. You will be able to see the GPU being used.
  2. Python Shell - You will be able to directly see the output. (Note- do not assign the output of the second command to the variable 'sess'; if that helps).
  3. Spyder - Type in the following command in the console.

    import tensorflow as tf tf.test.is_gpu_available()

Comments

1

If you are using TensorFlow 2.0, you can use this for loop to show the devices:

with tf.compat.v1.Session() as sess: devices = sess.list_devices() devices 

Comments

1

if you are using tensorflow 2.x use:

sess = tf.compat.v1.Session(config=tf.compat.v1.ConfigProto(log_device_placement=True)) 

Comments

1

I found the most simple and comprehensive approach. Just set tf.debugging.set_log_device_placement(True) and you should see if ops are actually run on GPU e.g. Executing op _EagerConst in device /job:localhost/replica:0/task:0/device:GPU:0

More in the docs: https://www.tensorflow.org/guide/gpu#logging_device_placement

1 Comment

That solution is great

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