Just to add to Simon's answer:
Objects are deleted by python's garbage collection mechanism once there are no
references left to the object. (keyword: reference counting).
The
del variable
statement Simon mention deletes the reference variable, but the memory is
freed only when python runs a garbage collection. That might immediately
afterwards, or slightly later (scheduled). Usually, you do not need to worry
about that and deleting the reference as Simon said is sufficient. If for some
reason you need to be absolutely sure that the object is garbage collected
immediately, you can trigger a garbage collection by
import gc
gc.collect()
Again, that should not be necessary, but it is useful to bear in mind how the
memory is actually handled in python.
Cheers,
Nils
On Jun 16 2023, at 9:10 am, Simon Rit <simon....@creatis.insa-lyon.fr> wrote:
>
>
> Hi,
>
>
> If you have a Python variable holding memory, you can simply call
>
>
> del variable_name
>
> If you want to clear the GPU memory for an image, you can access the CPU
> buffer pointer to have it moved to the computer RAM. Examples below.
>
> Simon
>
>
>
> >>> import os
>
> >>> os.system('nvidia-smi')
>
> Fri Jun 16 08:49:38 2023
>
> +-----------------------------------------------------------------------------+
>
> | NVIDIA-SMI 510.39.01 Driver Version: 510.39.01 CUDA Version:
> 11.6 |
>
> |-------------------------------+----------------------+----------------------+
>
> | GPU Name Persistence-M| Bus-Id Disp.A |
> Volatile Uncorr. ECC |
>
> | Fan Temp Perf Pwr:Usage/Cap| Memory-Usage |
> GPU-Util Compute M. |
>
> | |
> | MIG M. |
>
> |===============================+======================+======================|
>
> | 0 Quadro P2000 Off | 00000000:01:00.0 Off |
> N/A |
>
> | N/A 52C P8 N/A / N/A | 0MiB / 4096MiB |
> 0% Default |
>
> | |
> | N/A |
>
> +-------------------------------+----------------------+----------------------+
>
>
>
>
>
> +-----------------------------------------------------------------------------+
>
> | Processes:
> |
>
> | GPU GI CI PID Type Process name
> GPU Memory |
>
> | ID ID
> Usage |
>
> |=============================================================================|
>
> | No running processes found
> |
>
> +-----------------------------------------------------------------------------+
>
> 0
>
> >>> import itk
>
> >>> from itk import RTK as rtk
>
> >>> img=itk.CudaImage[itk.F, 3].New()
>
> >>> img.SetRegions([500]*3)
>
> >>> img.Allocate()
>
> >>> os.system('nvidia-smi')
>
> Fri Jun 16 08:51:28 2023
>
> +-----------------------------------------------------------------------------+
>
> | NVIDIA-SMI 510.39.01 Driver Version: 510.39.01 CUDA Version:
> 11.6 |
>
> |-------------------------------+----------------------+----------------------+
>
> | GPU Name Persistence-M| Bus-Id Disp.A |
> Volatile Uncorr. ECC |
>
> | Fan Temp Perf Pwr:Usage/Cap| Memory-Usage |
> GPU-Util Compute M. |
>
> | |
> | MIG M. |
>
> |===============================+======================+======================|
>
> | 0 Quadro P2000 Off | 00000000:01:00.0 Off |
> N/A |
>
> | N/A 58C P8 N/A / N/A | 45MiB / 4096MiB |
> 0% Default |
>
> | |
> | N/A |
>
> +-------------------------------+----------------------+----------------------+
>
>
>
>
>
> +-----------------------------------------------------------------------------+
>
> | Processes:
> |
>
> | GPU GI CI PID Type Process name
> GPU Memory |
>
> | ID ID
> Usage |
>
> |=============================================================================|
>
> | 0 N/A N/A 10890 C python
> 43MiB |
>
> +-----------------------------------------------------------------------------+
>
> 0
>
> >>> img.GetCudaDataManager().GetGPUBufferPointer()
>
> <Swig Object of type 'void *' at 0x7f20d3327f60>
>
> >>> os.system('nvidia-smi')
>
> Fri Jun 16 08:52:05 2023
>
> +-----------------------------------------------------------------------------+
>
> | NVIDIA-SMI 510.39.01 Driver Version: 510.39.01 CUDA Version:
> 11.6 |
>
> |-------------------------------+----------------------+----------------------+
>
> | GPU Name Persistence-M| Bus-Id Disp.A |
> Volatile Uncorr. ECC |
>
> | Fan Temp Perf Pwr:Usage/Cap| Memory-Usage |
> GPU-Util Compute M. |
>
> | |
> | MIG M. |
>
> |===============================+======================+======================|
>
> | 0 Quadro P2000 Off | 00000000:01:00.0 Off |
> N/A |
>
> | N/A 54C P0 N/A / N/A | 525MiB / 4096MiB |
> 0% Default |
>
> | |
> | N/A |
>
> +-------------------------------+----------------------+----------------------+
>
>
>
>
>
> +-----------------------------------------------------------------------------+
>
> | Processes:
> |
>
> | GPU GI CI PID Type Process name
> GPU Memory |
>
> | ID ID
> Usage |
>
> |=============================================================================|
>
> | 0 N/A N/A 10890 C python
> 523MiB |
>
> +-----------------------------------------------------------------------------+
>
> 0
>
> >>> del img
>
> >>> os.system('nvidia-smi')
>
> Fri Jun 16 08:52:21 2023
>
> +-----------------------------------------------------------------------------+
>
> | NVIDIA-SMI 510.39.01 Driver Version: 510.39.01 CUDA Version:
> 11.6 |
>
> |-------------------------------+----------------------+----------------------+
>
> | GPU Name Persistence-M| Bus-Id Disp.A |
> Volatile Uncorr. ECC |
>
> | Fan Temp Perf Pwr:Usage/Cap| Memory-Usage |
> GPU-Util Compute M. |
>
> | |
> | MIG M. |
>
> |===============================+======================+======================|
>
> | 0 Quadro P2000 Off | 00000000:01:00.0 Off |
> N/A |
>
> | N/A 56C P0 N/A / N/A | 2MiB / 4096MiB |
> 0% Default |
>
> | |
> | N/A |
>
> +-------------------------------+----------------------+----------------------+
>
>
>
>
>
> +-----------------------------------------------------------------------------+
>
> | Processes:
> |
>
> | GPU GI CI PID Type Process name
> GPU Memory |
>
> | ID ID
> Usage |
>
> |=============================================================================|
>
> | No running processes found
> |
>
> +-----------------------------------------------------------------------------+
>
> 0
>
> >>> img=itk.CudaImage[itk.F, 3].New()
>
> >>> img.SetRegions([500]*3)
>
> >>> img.GetCudaDataManager().GetGPUBufferPointer()
>
> <Swig Object of type 'void *' at 0x7f20b2c30870>
>
> >>> os.system('nvidia-smi')
>
> Fri Jun 16 08:54:10 2023
>
> +-----------------------------------------------------------------------------+
>
> | NVIDIA-SMI 510.39.01 Driver Version: 510.39.01 CUDA Version:
> 11.6 |
>
> |-------------------------------+----------------------+----------------------+
>
> | GPU Name Persistence-M| Bus-Id Disp.A |
> Volatile Uncorr. ECC |
>
> | Fan Temp Perf Pwr:Usage/Cap| Memory-Usage |
> GPU-Util Compute M. |
>
> | |
> | MIG M. |
>
> |===============================+======================+======================|
>
> | 0 Quadro P2000 Off | 00000000:01:00.0 Off |
> N/A |
>
> | N/A 58C P0 N/A / N/A | 525MiB / 4096MiB |
> 0% Default |
>
> | |
> | N/A |
>
> +-------------------------------+----------------------+----------------------+
>
>
>
>
>
> +-----------------------------------------------------------------------------+
>
> | Processes:
> |
>
> | GPU GI CI PID Type Process name
> GPU Memory |
>
> | ID ID
> Usage |
>
> |=============================================================================|
>
> | 0 N/A N/A 10890 C python
> 523MiB |
>
> +-----------------------------------------------------------------------------+
>
> 0
>
> >>> img.GetCudaDataManager().GetCPUBufferPointer()
>
> >>> os.system('nvidia-smi')
>
> Fri Jun 16 08:54:20 2023
>
> +-----------------------------------------------------------------------------+
>
> | NVIDIA-SMI 510.39.01 Driver Version: 510.39.01 CUDA Version:
> 11.6 |
>
> |-------------------------------+----------------------+----------------------+
>
> | GPU Name Persistence-M| Bus-Id Disp.A |
> Volatile Uncorr. ECC |
>
> | Fan Temp Perf Pwr:Usage/Cap| Memory-Usage |
> GPU-Util Compute M. |
>
> | |
> | MIG M. |
>
> |===============================+======================+======================|
>
> | 0 Quadro P2000 Off | 00000000:01:00.0 Off |
> N/A |
>
> | N/A 58C P0 N/A / N/A | 47MiB / 4096MiB |
> 0% Default |
>
> | |
> | N/A |
>
> +-------------------------------+----------------------+----------------------+
>
>
>
>
>
> +-----------------------------------------------------------------------------+
>
> | Processes:
> |
>
> | GPU GI CI PID Type Process name
> GPU Memory |
>
> | ID ID
> Usage |
>
> |=============================================================================|
>
> | 0 N/A N/A 10890 C python
> 45MiB |
>
> +-----------------------------------------------------------------------------+
>
> 0
>
>
>
>
>
> On Thu, Jun 15, 2023 at 5:33 PM Rahman, Obaid <rahm...@ornl.gov
> (mailto:rahm...@ornl.gov)> wrote:
>
>
> >
> >
> > Hi,
> >
> >
> >
> > I am using ink-rtk-cuda116 with python.
> >
> > I have too many cuda variables (images and filters).
> >
> > I would like to clear some of these variables.
> >
> >
> >
> > I am getting the following error:
> >
> > ITK ERROR: CUDA ERROR: out of memory
> >
> >
> >
> > Does anyone know how to clear Cuda variables in python?
> >
> > Thanks.
> >
> >
> >
> > Best,
> >
> > Obaidullah Rahman
> >
> >
> > Oak Ridge National Laboratory, TN, United States
> >
> >
> > _______________________________________________
> >
> > Rtk-users mailing list
> >
> > rtk-us...@openrtk.org (mailto:rtk-us...@openrtk.org)
> >
> > https://www.creatis.insa-lyon.fr/mailman/listinfo/rtk-users
> >
>
>
>
> _______________________________________________
>
> Rtk-users mailing list
>
> rtk-us...@openrtk.org
>
> https://www.creatis.insa-lyon.fr/mailman/listinfo/rtk-users
>
>
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