Schedule Transferability between Intel and ARM CPU targets

[anijain2305]

Relevant discuss post - https://discuss.tvm.ai/t/topi-using-x86-schedules-for-arm-conv2d/6365

Currently, TVM has different schedules for ARM and Intel for conv2d operators. The discuss post listed above shows that Intel conv2d NCHWc schedule on ARM gives better end-to-end latency compared to ARM NCHW conv2d spatial pack schedule for many TFLite networks.

However, this is just one opportunity and there are also some more ideas that we should pursue. This issue lists those potential issues and anybody interested can pick them up. This list is a result of discussions from the above post.

• Try ARM winograd NCHW schedule on Intel servers.
• Write NCHWc winograd for Intel servers to comply with existing NCHWc conv2d implementation - work started by @ajtulloch -[X86] [NNVM] [TOPI] Implement NCHWc Winograd convolutions #2111
• Work on NHWC ARM schedule - tuning and optimization - work started by @jackwish - [TOPI][AutoTVM] NHWC conv2d templates for ARM #3859
• Investigate NHWC vs NCHWc schedule - NCHWc can bring data layouts transform. Check if NHWC can achieve same performance as NCHWc conv2d, and eliminate data layout conversion overhead.

@FrozenGene @masahi @tqchen

[zhenhuaw-me]

That is really good idea that we can share schedules across backends!
A few monthes ago, I had once thought that, maybe we can modularize TOPI such that some well known schedules can be shared as much as possible. For example, we can have schedules for CPU and GPU which could shared between x86/ARM/... and CUDA/OpenCL respectively. Though I am not actively working on TVM nowdays, hoping to contribute someday still.

[tqchen]

@anijain2305 please check if we can close this issue either due to non-actionable status(stale) or completion

[anijain2305]

I think we can close this. As Ansor comes in, we will try these different choices automatically on all platforms.