mlx VS faster-whisper

Yes, we are also looking at integrating MLX [1] which is optimized for Apple Silicon and built by an incredible team of individuals, a few of which were behind the original Torch [2] project. There's also TensorRT-LLM [3] by Nvidia optimized for their recent hardware.

All of this of course acknowledging that llama.cpp is an incredible project with competitive performance and support for almost any platform.

[1] https://github.com/ml-explore/mlx

[2] https://en.wikipedia.org/wiki/Torch_(machine_learning)

[3] https://github.com/NVIDIA/TensorRT-LLM

If you're able to purchase a separate GPU, the most popular option is to get an NVIDIA RTX3090 or RTX4090.

Apple Mac M2 or M3's are becoming a viable option because of MLX https://github.com/ml-explore/mlx . If you are getting an M series Mac for LLMs, I'd recommend getting something with 24GB or more of RAM.

3) Not Enough Benefit (For the Cost... Yet!)

This is my best understanding based on my own work and research for a local LLM iOS app. Read on for more in-depth justifications of each point!

-—-

1) No Neural Engine API

- There is no developer API to use the Neural Engine programmatically, so CoreML is the only way to be able to use it.

2) CoreML has challenges modeling LLMs efficiently right now.

- Its most-optimized use cases seem tailored for image models, as it works best with fixed input lengths[1][2], which are fairly limiting for general language modeling (are all prompts, sentences and paragraphs, the same number of tokens? do you want to pad all your inputs?).

- CoreML features limited support for the leading approaches for compressing LLMs (quantization, whether weights-only or activation-aware). Falcon-7b-instruct (fp32) in CoreML is 27.7GB [3], Llama-2-chat (fp16) is 13.5GB [4] — neither will fit in memory on any currently shipping iPhone. They'd only barely fit on the newest, highest-end iPad Pros.

- HuggingFace‘s swift-transformers[5] is a CoreML-focused library under active development to eventually help developers with many of these problems, in addition to an `exporters` cli tool[6] that wraps Apple's `coremltools` for converting PyTorch or other models to CoreML.

3) Not Enough Benefit (For the Cost... Yet!)

- ANE & GPU (Metal) have access to the same unified memory. They are both subject to the same restrictions on background execution (you simply can't use them in the background, or your app is killed[7]).

- So the main benefit from unlocking the ANE would be multitasking: running an ML task in parallel with non-ML tasks that might also require the GPU: e.g. SwiftUI Metal Shaders, background audio processing (shoutout Overcast!), screen recording/sharing, etc. Absolutely worthwhile to achieve, but for the significant work required and the lack of ecosystem currently around CoreML for LLMs specifically, the benefits become less clear.

- Apple's hot new ML library, MLX, only uses Metal for GPU[8], just like Llama.cpp. More nuanced differences arise on closer inspection related to MLX's focus on unified memory optimizations. So perhaps we can squeeze out some performance from unified memory in Llama.cpp, but CoreML will be the only way to unlock ANE, which is lower priority according to lead maintainer Georgi Gerganov as of late this past summer[9], likely for many of the reasons enumerated above.

I've learned most of this while working on my own private LLM inference app, cnvrs[10] — would love to hear your feedback or thoughts!

Britt

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[1] https://github.com/huggingface/exporters/pull/37

[2] https://apple.github.io/coremltools/docs-guides/source/flexi...

[3] https://huggingface.co/tiiuae/falcon-7b-instruct/tree/main/c...

[4] https://huggingface.co/coreml-projects/Llama-2-7b-chat-corem...

[5] https://github.com/huggingface/swift-transformers

[6] https://github.com/huggingface/exporters

[7] https://developer.apple.com/documentation/metal/gpu_devices_...

[8] https://github.com/ml-explore/mlx/issues/18

[9] https://github.com/ggerganov/llama.cpp/issues/1714#issuecomm...

[10] https://testflight.apple.com/join/ERFxInZg

Maybe MLX is meant to fill this gap?

https://github.com/ml-explore/mlx

This is basically fork of llama.cpp. I created a PR to see the diff and added my comments on it: https://github.com/ggerganov/llama.cpp/pull/4543

One thing that caught my interest is this line from their readme:

> PowerInfer exploits such an insight to design a GPU-CPU hybrid inference engine: hot-activated neurons are preloaded onto the GPU for fast access, while cold-activated neurons are computed on the CPU, thus significantly reducing GPU memory demands and CPU-GPU data transfers.

Apple's Metal/M3 is perfect for this because CPU and GPU share memory. No need to do any data transfers. Checkout mlx from apple: https://github.com/ml-explore/mlx

How does this compare to insanely-fast-whisper though? https://github.com/Vaibhavs10/insanely-fast-whisper

I think that not using optimizations allows this to be a 1:1 comparison, but if the optimizations are not ported to MLX, then it would still be better to use a 4090.

Having looked at MLX recently, I think it's definitely going to get traction on Macs - and iOS when Swift bindings are released https://github.com/ml-explore/mlx/issues/15 (although there might be some C++20 compilation issue blocking right now).

software is already there, check the new ml framework from Apple https://github.com/ml-explore/mlx

Faster-whisper (https://github.com/SYSTRAN/faster-whisper)

For our real-time STT needs, we'll employ a fantastic library called faster-whisper.

Thermostats: https://www.sinopetech.com/en/products/thermostat/

I haven't tried running a local text-to-speech engine backed by an LLM to control Home Assistant. Maybe someone is working on this already?

TTS: https://github.com/SYSTRAN/faster-whisper

LLM: https://github.com/Mozilla-Ocho/llamafile/releases

LLM: https://huggingface.co/TheBloke/Nous-Hermes-2-Mixtral-8x7B-D...

It would take some tweaking to get the voice commands working correctly.

Could someone elaborate how is this accomplished and is there any quality disparity compared to original whisper?

Repos like https://github.com/SYSTRAN/faster-whisper makes immediate sense about why it's faster than the original, but this one, not so much, especially considering it's even much faster.

Cool! I had the same project idea recently. You may be interested in this for the step of speech2text: https://github.com/SYSTRAN/faster-whisper

That's the implication. If the distil models are same format as original openai models then the Distil models can be converted for faster-whisper use as per the conversion instructions on https://github.com/guillaumekln/faster-whisper/

So then we'll see whether we get the 6x model speedup on top of the stated 4x faster-whisper code speedup.

> While I agree that it's much more effort to get things working on AMD cards than it is with Nvidia, I was a bit surprised to see this comment mention Whisper being an example of "5-10x as performant".

It easily is. See the benchmarks[0] from faster-whisper which uses Ctranslate2. That's 5x faster than OpenAI reference code on a Tesla V100. Needless to say something like a 4080 easily multiplies that.

> https://www.tomshardware.com/news/whisper-audio-transcriptio... is a good example of Nvidia having no excuses being double the price when it comes to Whisper inference, with 7900XTX being directly comparable with 4080, albeit with higher power draw. To be fair it's not using ROCm but Direct3D 11, but for performance/price arguments sake that detail is not relevant.

With all due respect to the author of the article this is "my first entry into ML" territory. They talk about a 5-10 second delay, my project can do sub 1 second times[1] even with ancient GPUs thanks to Ctranslate2. I don't have an RTX 4080 but if you look at the performance stats for the closest thing (RTX 4090) the performance numbers are positively bonkers - completely untouchable for anything ROCm based. Same goes for the other projects I linked, lmdeploy does over 100 tokens/s in a single session with LLama2 13b on my RTX 4090 and almost 600 tokens/s across eight simultaneous sessions.

> EDIT: Also using CTranslate2 as an example is not great as it's actually a good showcase why ROCm is so far behind CUDA: It's all about adapting the tech and getting the popular libraries to support it. Things usually get implemented in CUDA first and then would need additional effort to add ROCm support that projects with low amount of (possibly hobbyist) maintainers might not have available. There's even an issue in CTranslate2 where they clearly state no-one is working to get ROCm supported in the library. ( https://github.com/OpenNMT/CTranslate2/issues/1072#issuecomm... )

I don't understand what you're saying here. It (along with the other projects I linked) are fantastic examples of just how far behind the ROCm ecosystem is. ROCm isn't even on the radar for most of them as your linked issue highlights.

Things always get implemented in CUDA first (ten years in this space and I've never seen ROCm first) and ROCm users either wait months (minimum) for sub-par performance or never get it at all.

[0] - https://github.com/guillaumekln/faster-whisper#benchmark

[1] - https://heywillow.io/components/willow-inference-server/#ben...

guillaumekln/faster-whisper

Neat to see a new implementation, although I'll note that for those looking for a drop-in replacement for the whisper library, I believe that both faster-whisper https://github.com/guillaumekln/faster-whisper and https://github.com/m-bain/whisperX are easier (PyTorch-based, doesn't require a web browser), and a lot faster (WhisperX is up to 70X realtime).

One caveat here is that whisper.cpp does not offer any CUDA support at all, acceleration is only available for Apple Silicon.

If you have Nvidia hardware the ctranslate2 based faster-whisper is very very fast: https://github.com/guillaumekln/faster-whisper