A lot of GPU-errors when doing windowPoSt's on CPU

[rjan90]

Describe the bug
There seems to be a lot of GPU-errors on a miner doing windowPoSt's with a CPU. Some of the logs even shows that "GPU is available for FFT!" even though the server does not have a GPU.

windowPoSt start:

2021-02-08T02:52:00.428+0100	WARN	storageminer	storage/wdpost_run.go:225	Checked sectors	{"checked": 42, "good": 42}
2021-02-08T02:52:00.437+0100	INFO	storageminer	storage/wdpost_run.go:578	running window post	{"chain-random": "9NsXzaLwmfPakdJS07Y61gYhG291h7Grw7EntgwmgO0=", "deadline": {"CurrentEpoch":481424,"PeriodStart":481324,"Index":2,"Open":481444,"Close":481504,"Challenge":481424,"FaultCutoff":481374,"WPoStPeriodDeadlines":48,"WPoStProvingPeriod":2880,"WPoStChallengeWindow":60,"WPoStChallengeLookback":20,"FaultDeclarationCutoff":70}, "height": "481424", "skipped": 0}
2021-02-08T02:52:00.438 INFO filcrypto::proofs::api > generate_window_post: start
2021-02-08T02:52:05.279 INFO filecoin_proofs::api::post > generate_window_post:start 

GPU-errors (there is no GPU in the server:

2021-02-08T02:53:26.987 INFO bellperson::gpu::locks > GPU is available for FFT!
2021-02-08T02:53:26.987 WARN bellperson::domain > Cannot instantiate GPU FFT kernel! Error: GPUError: No working GPUs found!
2021-02-08T02:53:58.492 INFO bellperson::gpu::locks > GPU is available for FFT!
2021-02-08T02:53:58.492 WARN bellperson::domain > Cannot instantiate GPU FFT kernel! Error: GPUError: No working GPUs found!
2021-02-08T02:54:27.105 INFO bellperson::gpu::locks > GPU is available for FFT!
2021-02-08T02:54:27.107 WARN bellperson::domain > Cannot instantiate GPU FFT kernel! Error: GPUError: No working GPUs found!
2021-02-08T02:54:56.645 INFO bellperson::gpu::locks > GPU is available for FFT!
2021-02-08T02:54:56.647 WARN bellperson::domain > Cannot instantiate GPU FFT kernel! Error: GPUError: No working GPUs found!
2021-02-08T02:55:25.018 INFO bellperson::gpu::locks > GPU is available for FFT!
2021-02-08T02:55:25.020 WARN bellperson::domain > Cannot instantiate GPU FFT kernel! Error: GPUError: No working GPUs found!
2021-02-08T02:55:55.442 INFO bellperson::gpu::locks > GPU is available for FFT!
2021-02-08T02:55:55.444 WARN bellperson::domain > Cannot instantiate GPU FFT kernel! Error: GPUError: No working GPUs found!
2021-02-08T02:56:27.607 INFO bellperson::gpu::locks > GPU is available for FFT!
2021-02-08T02:56:27.609 WARN bellperson::domain > Cannot instantiate GPU FFT kernel! Error: GPUError: No working GPUs found!
2021-02-08T02:57:37.168 INFO bellperson::gpu::locks > GPU is available for Multiexp!
2021-02-08T02:57:37.168 WARN bellperson::multiexp > Cannot instantiate GPU Multiexp kernel! Error: GPUError: No working GPUs found!
2021-02-08T03:00:45.728 INFO bellperson::gpu::locks > GPU is available for Multiexp!
2021-02-08T03:00:45.728 WARN bellperson::multiexp > Cannot instantiate GPU Multiexp kernel! Error: GPUError: No working GPUs found!
2021-02-08T03:03:34.166 INFO bellperson::gpu::locks > GPU is available for Multiexp!
2021-02-08T03:03:34.168 WARN bellperson::multiexp > Cannot instantiate GPU Multiexp kernel! Error: GPUError: No working GPUs found!
2021-02-08T03:03:34.223 INFO bellperson::gpu::locks > GPU is available for Multiexp!
2021-02-08T03:03:34.223 WARN bellperson::multiexp > Cannot instantiate GPU Multiexp kernel! Error: GPUError: No working GPUs found!
2021-02-08T03:05:47.062 INFO bellperson::gpu::locks > GPU is available for Multiexp!
2021-02-08T03:05:47.064 WARN bellperson::multiexp > Cannot instantiate GPU Multiexp kernel! Error: GPUError: No working GPUs found!
2021-02-08T03:05:47.065 INFO bellperson::gpu::locks > GPU is available for Multiexp!
2021-02-08T03:05:47.065 WARN bellperson::multiexp > Cannot instantiate GPU Multiexp kernel! Error: GPUError: No working GPUs found!
2021-02-08T03:08:11.241 INFO bellperson::gpu::locks > GPU is available for Multiexp!
2021-02-08T03:08:11.243 WARN bellperson::multiexp > Cannot instantiate GPU Multiexp kernel! Error: GPUError: No working GPUs found!
2021-02-08T03:08:11.245 INFO bellperson::gpu::locks > GPU is available for Multiexp!
2021-02-08T03:08:11.245 WARN bellperson::multiexp > Cannot instantiate GPU Multiexp kernel! Error: GPUError: No working GPUs found!

windowPoSt finished:

2021-02-08T03:12:57.641 INFO filecoin_proofs::api::post > generate_window_post:finish
2021-02-08T03:12:57.693 INFO filcrypto::proofs::api > generate_window_post: finish
2021-02-08T03:12:57.693+0100	INFO	storageminer	storage/wdpost_run.go:594	computing window post	{"batch": 0, "elapsed": 1257.255951528}
2021-02-08T03:12:58.032+0100	INFO	storageminer	storage/wdpost_run.go:750	Submitted window post: bafy2bzacecrvyonjvxlnvoh7o27dkjjhdqjyltwx3m4jf7oug7knhzcvwvsto

To Reproduce
Steps to reproduce the behavior:

1. Run windowPoSt's with a CPU on server without GPU
2. See error

Expected behavior
This might be a minor/cosmetic issue, as I'm not sure if it there is any performance-downsides by having the miner thinking there is a GPU there, but I expected the logs to not show that there is GPU there, when there is none!

Version (run lotus version):
Daemon: 1.4.0+git.e9989d0e4+api1.0.0
Local: lotus version 1.4.0+git.e9989d0

[dignifiedquire]

This is the expected behaviour at the moment.

WARN  Cannot instantiate GPU Multiexp kernel! Error: GPUError: No working GPUs found!

is printed to make clear that no GPU is available, and it is always done so when a new task is started. This should have no performance impact.

GPU is available for Multiexp!

is a log message about the internal lock handling for GPUs, which is slightly misleading in this case, but there is no error here. I just means that the GPU lock is available, which it is always because no GPU is actually being used.

[rjan90]

Great! Thanks for the answer!