nbdkit-vram-plugin - use GPU Video RAM as a network block device
nbdkit vram -f [device=NAME|N] [SIZE] nbdkit vram --dump-pluginnbdkit-vram-plugin is a plugin for nbdkit(1) which uses Video RAM from an OpenCL-capable graphics card (GPU) as a block device.
You currently must run the plugin in the foreground (nbdkit -f option).
Video RAM is volatile. As soon as nbdkit exits or the machine is turned off, the disk and all data on it is deleted.
To check that OpenCL is installed and sees your GPU, run clinfo(1):
$ clinfo --list
Platform #0: AMD Accelerated Parallel Processing
+-- Device #0: gfx1101
`-- Device #1: gfx1036
$ clinfo
Number of platforms 1
Platform Name AMD Accelerated Parallel Processing
Platform Vendor Advanced Micro Devices, Inc.
Platform Version OpenCL 2.1 AMD-APP (3649.0)
...
Number of devices 2
Device Name gfx1101
Device Vendor Advanced Micro Devices, Inc.
Device Vendor ID 0x1002
Device Version OpenCL 2.0
...
Global memory size 17163091968 (15.98GiB)
...
Device Name gfx1036
Device Vendor Advanced Micro Devices, Inc.
Device Vendor ID 0x1002
Device Version OpenCL 2.0
...
Global memory size 33247174656 (30.96GiB)If there is more than one device in the system, use the device parameter with the device name or index (counting from 0). For example:
$ nbdkit -f vram device=gfx1101 $ nbdkit -f vram device=0To see what devices the plugin sees, use:
$ nbdkit vram --dump-plugin
...
vram_num_devices=2
vram_device_index=0
vram_device_name=gfx1101
...
vram_device_index=1
vram_device_name=gfx1036By default, the plugin will try to use as much of the video RAM on the device as possible. You can limit the RAM to a smaller amount using the optional size parameter, eg:
$ nbdkit -f vram 10GThe plugin allocates video RAM on demand as you fill it up with data. This means that if there are other users of the GPU (for example, you are running a game at the same time), it is possible to run out of space. In this case, writes will return ENOSPC "No space left on device" errors.
To limit the maximum amount of video RAM that will be used, use the optional size parameter.
If you trim the block device (eg. fstrim(8)), video RAM is given back to the system.
Currently you cannot limit the video RAM used independently of the virtual size of the disk (because it's not a good idea).
Integrated graphics GPUs (where the GPU is part of the CPU) usually use system RAM as video RAM. Therefore there is no point using this plugin with integrated graphics. Use nbdkit-memory-plugin(1) to use system RAM as a RAM disk instead.
Choose the GPU by OpenCL name or by device index (counting from 0).
To list the devices known to OpenCL, use the clinfo(1) command.
If you are not sure what device name or index to use, consult the output of nbdkit vram --dump-plugin
Limit the size of the video RAM disk. If omitted, the plugin will try to use all available video RAM on the device.
Note this may be rounded up by the plugin (currently to a multiple of 64K).
size= prefix may be omitted in most cases. See "Magic parameters" in nbdkit(1).
Various environment variables are passed through to OpenCL and the OpenCL driver. Please consult documentation for your GPU.
The plugin.
Use nbdkit --dump-config to find the location of $plugindir.
nbdkit-vram-plugin first appeared in nbdkit 1.46.
nbdkit(1), nbdkit-plugin(3), nbdkit-memory-plugin(1), clinfo(1), fstrim(8).
Richard W.M. Jones
This plugin was heavily inspired by vramfs, a FUSE module written by Alexander Overvoorde (https://github.com/Overv/vramfs).
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