Eval bug: clip.cpp has no GPU support - a lot of work is at risk

[cmp-nct]

Name and Version

all versions 2025

Operating systems

Linux

GGML backends

CUDA, Metal

Hardware

any

Models

No response

Problem description & steps to reproduce

In PR #10896 the GPU support of clip.cpp has been removed, it's basically just a few comments around fullly functional code.

Hundreds of hours went into CLIP and having it on GPU support was a major feat for the vision capabilities of llama.cpp, this also caused large SOTA models to be implemented in llama.cpp with people working dedicated on those patches.

I agree that the vision implementation was not great but we've had SOTA support by models like minicpm-v-2.6 and even the new minicpmv-o-2.6 has been implemented in llama.cpp at launch with dedicated people working on it with a current PR waiting for merge.

This change renders those models useless for anyone who is not aware on how to hack the llama.cpp code. It takes minutes instead of milliseconds now.

I strongly recommend to add the GPU support back into clip.cpp while it is still compatible (currently it is) with the core so people can use llama.cpp with vision capabilities again.
To prevent people posting unwelcome issues, add a warning message instead.
Right now we see issues being created that vision support is not working anymore, that GPU support is failing etc. Longterm it will cause developers to stop support llama.cpp as engine for vision.

First Bad Commit

#10896

Relevant log output

-

[ngxson]

I'm working on vision APi refactoring, and I can confirm that enabling GPU (I'm using Metal backend) make it crashes

[cmp-nct]

I'm working on vision APi refactoring, and I can confirm that enabling GPU (I'm using Metal backend) make it crashes

great to hear you are on it :)
On Cuda the backend works, minicpm takes 500ms on GPU when it takes 1-2 minutes on CPU.
Maybe we can just enable the backends that do work, CUDA is a huge step given the popularity of nvidia cards.

[ngxson]

OK thanks for the info. I don't know who disabled it in the first place, but will see after I finish my initial refactoring

[ekk1]

I can confirm MiniCPM-o 2.6 with their fork of llama.cpp works with CUDA support in CLIP

following https://github.com/OpenBMB/llama.cpp/blob/minicpmv-main/examples/llava/README-minicpmv2.6.md

and modify examples/llava/clip.cpp, uncomment CUDA related comments, rebuild with cmake
the speedup is significant, from 16000+ ms -> 40+ ms (16t Intel 8352V -> 4090 )

note:
examples/llava/minicpmv-cli.cpp may also needs to be modified, change the value 256 to whatever you need, otherwise the inference will be prematurely interrupted.

[nick-pape]

OK thanks for the info. I don't know who disabled it in the first place, but will see after I finish my initial refactoring

ggerganov removed it here

[cmp-nct]

Yea, it appears there were lots of issue reports and gg got annoyed by the state of the llava-like examples.
I've no idea what those issues were about but I've used clip on CUDA and many visual models in extensive tests, very successfully.

I think the problem was the refactor of the gguf backend system, during that all backends were added into clip.cpp and before that clip.cpp ONLY had CUDA enabled.

So my recommendation is to enable CUDA again, other acceleration backends only if someone has tested them well.
It's just 3 lines of code to make clip work with cuda.

[0cc4m]

Then open a PR and discuss it with gg. I think it should also still be working on Vulkan, but I'd have to test it.

[LostRuins]

It is still working on Vulkan and Metal for most architectures except Qwen2VL. On CUDA its fine on all architectures.

[jeffbolznv]

Vulkan should work on Qwen2VL now after #11902. The issue was some missing rope variants. If somebody makes a PR to reenable for CUDA, please also reenable for Vulkan.

[ngxson]

Could someone please test this PR on your backend: #12322

I've tested on Metal and it works fine despite op Conv2d not supported by Metal (the ggml sched automatically use CPU for non-supported ops)

Would be nice if someone can test on CUDA, SYCL and Vulkan

[vladislavdonchev]

I've tested with Qwen2 and a few other models using Vulkan. Everything seems to be working fine.

I am trying to gather all of the data in a document.