diff options
Diffstat (limited to 'README.md')
| -rw-r--r-- | README.md | 22 |
1 files changed, 22 insertions, 0 deletions
@@ -182,6 +182,28 @@ and unblocks any waiting user space processes.  +# Multi subsystem + +The Ethos-U subsystem is also referred to as the *ML Island*. A device with +multiple subsystems is therefor called both *Multi Subsystem* and *Multi +Island*. A subsystem may contain a single- or multiple NPUs, also referred to as +*multi NPU subsystem*. + +The NPUs within a subsystem must be of identical configuration. However, NPUs +belonging to separate subsystems may be of different architectures. + +For each subsystem there is a device tree entry, which will result in a separate +device node `/dev/ethosu<nr>` being created by the Ethos-U kernel driver. For +multi NPU subsystems there will still only be one device node per subsystem. The +distribution of inferences within a subsystem is handled by the software running +on the Cortex-M. + +Buffers used to store networks, IFMs and OFMs are allocated from the device +node. This is because only the device node knows where to allocate the memory +and how to translate Linux logical addresses to subsystem DMA addresses. As a +consequence buffers, networks and inferences are bound to a device node and +can't be easily moved. + # Licenses The kernel drivers are provided under a GPL v2 license. All other software |