DiffusionGemma#24423
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Some diffusion cli and visual updates
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Hi @danielhanchen, thanks for your contribution! Per our contribution guidelines, the automated PR checker found the following issue(s) that need your attention:
Please note that maintainers reserve the right to make final decisions on PRs. If you believe there is a mistake, please comment below. |
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Oof, that's a big one. There's a ton of debugging stuff left in there that needs throwing out, for one. I'm also not convinced about the idea to make a server just for one model - I think if we're intending to support diffusion models in a server mechanism, it should be a general diffusion-server (but that's just my opinion, probably have to wait for what @ggerganov thinks about this one). |
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Haha sorry - this PR was more of a direct translation / proof of concept that it works! |
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I'll edit the PR - sorry we're juggling multiple things haha |
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Another PR for DiffusionGemma: #24427 |
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You have some failing tests to fix. :) |
With a block diffusion model, couldn't the regular server just return each block when it is finished diffusing? It would be nice to just have one server, and the API could remain fully compatible so clients don't need to be aware that they're dealing with a diffusion model. (We don't show the distribution of sampled logits for AR models, and I don't see why people would need to see the intermediate diffusion steps either, since those won't be useful.) |
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Doesn't build on Windows: |
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Yep will fix haha - I also added a short GIF of it working edited in description! |
…s, drop debug hooks - guard sys/ioctl.h behind _WIN32 and add a GetConsoleScreenBufferInfo fallback for the visual viewport size, so diffusion-cli builds on Windows - skip diffusion-gemma in test-llama-archs like gemma4 (shared ISWA backbone, no synthetic fixture params yet) - remove the DG_DUMP_KV_LAYER / DG_NSWA debug scaffolding and its llama.h API - fix flake8 E306 in conversion/diffusion_gemma.py
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I was able to compile it successfully on Linux for my 4090, but when running it, I get the following error after sending a user message: The command I'm running is: To compile it, I used: |
Builds and runs on Windows now. |
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is it only cli at this point? no llama-server ? |
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Thank you for putting this together! An Issue I found is that --fit doesn't work with this PR. |
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Test run on my system with AMD hardware (7900 XTX) in it, Q4_K_M - time per step: 364.45ms Screencast_20260610_234032_c.webm |
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@icedream What (equivalent) tokens per second are you getting? I also tried running it with an AMD GPU (R9700 w/ vulkan) and only got ~27t/s. |
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@lucasbinder Not 100% sure if that's the right way to calculate it but based on two more runs with the same prompt, calculating with 256 tokens per full canvas diffused (I left out the last canvas as tail end of response), taking the start/end timings per canvas from the Run 1 2.327213 - 9.803998 = 7.476785 = 34.24 t/s Run 2 2.328457 - 9.777839 = 7.449382 = 34.37 t/s (Also I should clarify I used ROCm, not Vulkan in my case so that may be influencing the performance as well.) |
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Unofficial prebuilt binaries for anyone who wants to test this PR without setting up a CUDA toolchain: https://github.com/gbuznote-beep/llama-diffusion-cli-prebuilt
Data points from testing (256 tokens, EB sampler): A5000 full-GPU 0.98 s/step; RTX 3070 Ti Laptop 8 GB via WSL2 ( |
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./llama-server -m /data3/diffusiongemma-26B-A4B-it-Q4_K_M.gguf -t 96 --port 2604 --host 0.0.0.0 Server Error |
…anvas The visual server forced n_ubatch == n_ctx, so the whole prompt went through one non-causal encode. The O(prompt^2) attention overflows the 32-bit CUDA softcap index past ~12k tokens (n_head * N^2 > 2^31, a crash), and the encode also built an [n_tokens, n_vocab] fp32 logits buffer it then discarded. - llama-context: encode() honors cparams.n_outputs_max and reserves/copies only the flagged rows (no-op when n_outputs_max >= n_tokens). - diffusion-gemma: prefill the prompt in n_ubatch-sized causal chunks into a grow-only K/V store at an offset; off=0 is the single-shot prefill. - visual server: cap n_outputs_max to the canvas and size the prefill chunk so n_head * chunk * n_ctx stays under 2^31 (2048 up to ~32k, smaller past that). The per-turn compute buffer is now flat ~566 MiB regardless of context, output is byte-identical when the prompt fits one ubatch, and prompts to 60k+ tokens work where the single-shot encode crashed. Chunked-prefill approach from potto007.
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I wasn't able to get this to work on ROCm until I made some changes to the ggml backend. in src/models/diffusion-gemma.cpp the function llama_diffusion_device_sample() the lines does not register as CUDA because it fails to host fallback. I added a basic fallthrough to catch ROCm: Then the diffusion sampler worked. |
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I tested it with the KV prompt store set to Q4 and I didn't see any degradation of output or reasoning - was able to run it with Cline with a context window size of 131k tokens. Fixed a bug where the CoT was being fed back to the model, which is explicitly stated in the Gemma family model cards as needing to be omitted. That was causing it to stop mid-turn -- after fixing that, I was able to have it successfully read the contents of one of my projects and reason about the code. Rough stopwatch timings so far, but it tends to run about 2x faster than my local llamacpp-run gemma-4-12b. |
Integriert DiffusionGemma (block text-diffusion MoE auf Gemma-4 Backbone) als monolithischen Port, da unser Fork die upstream llama_model_base- Hierarchie (Commit 994118a, 2026-05-04) noch nicht hat. Geaendert: - llama-arch.h/.cpp: LLM_ARCH_DIFFUSION_GEMMA, 5 neue Tensor-Typen, 7 Diffusion-KV-Keys (canvas_length, eb_*) - llama-model.h: Diffusion-spezifische Felder (canvas_length, sc_*, pkv_*) - llama-model.cpp: 4 Cases fuer load_hparams, load_tensors, build_graph, type_name Mapping - llama-model-loader.cpp: Template-Instanziierung get_key<int64_t> - include/llama.h: C-API Erweiterungen (diffusion_set_sc, set_phase) - models.h: Forward declaration llm_build_diffusion_gemma - gemma4-common.h: llm_graph_qkv Helper-Struct - diffusion-gemma.cpp: Monolithischer Graph-Builder (547 Zeilen) - tools/diffusion-cli: Minimales CLI-Tool fuer Tests - common/arg.cpp + common.h: CLI-Flags fuer Diffusion-Parameter - gguf-py: DiffusionGemma Arch/Tensor/KV-Mappings - tests/test-llama-archs.cpp: Arch in Skip-Listen eingetragen Neu (aus PR ggml-org#24423, unveraendert uebernommen): - conversion/diffusion_gemma.py: HF->GGUF Konvertierung - ggml-cuda/diffusion-sampling.cu: CUDA-Kernels fuer Diffusion-Sampling - pocs/: Dokumentation (Entscheidung, Masterplan, Status) Getestet: - Build erfolgreich (libllama.so, llama-server, llama-cli, llama-diffusion-cli) - Modell-Loading: Q4_K_M laeuft (25.25B Parameter) - Inferenz: Einzelner Forward-Pass mit greedy decode - GPU-Offloading: 8 Layers auf RTX 3070 Laptop (~2.5 t/s) Offen: - Echter Diffusion-Decoding-Loop (Prefill -> bidirektionaler Decode x N) - Entropy-bound Decoder - Visual Diffusion Mode - Upstream-Tools (diffusion-gemma-eval, -server) bauen nicht
Portiert aus PR ggml-org#24423 (Unsloth). Der Entropy-Bound Decoder ist der Kern-Algorithmus von DiffusionGemma: - Canvas mit zufaelligen Tokens initialisiert - Pro Step: Argmax, Entropie, Multinomial-Sample pro Position - Acceptance nach Entropie-Bound (niedrigste zuerst) - Renoising: nicht-akzeptierte Positionen -> frisches Rauschen - Output = Argmax-Canvas (nicht gesampelte Tokens) - Lineare Temperatur-Schedule (t_max -> t_min) - Konvergenz: Stabilitaet + Konfidenz Technisch funktionsfaehig. Output-Qualitaet verbesserbar durch: - Self-Conditioning (SC-Tensoren fehlen noch) - Mehr Steps (20 getestet, 48 empfohlen) - Chat-Template Prompt-Formatierung
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| diff_params.mask_token_id = mask_token_id; | ||
| diff_params.seed = params.sampling.seed; |
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When the CLI doesn't pass a seed, the output will be exactly the same. Please refer to 'get_rng_seed'.
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On my strix halo AI MAX 395(windows vulkan), it can only run at 10 tok/s because it frequently outputs "W ggml_vulkan: Failed to allocate pinned memory (Requested buffer size exceeds device buffer size limit: ErrorOutOfDeviceMemory)", even though the RAM and VRAM aren't even half used. I tried making some changes with GPT, forcing |
…dates # Conflicts: # include/llama.h
The Stage-1 device sampler looked up the ggml-cuda backend by the literal name "CUDA", so on HIP and MUSA builds (registered as "ROCm"/"MUSA") the lookup failed and every step fell back to the host logits path. The backend exports the same ggml_backend_cuda_diffusion_sample proc address from shared source regardless of build, so probe ROCm and MUSA as well. Reported by aaronsb.
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Hey everybody, I missed the rule of no generated output with my previous comment. My bad, anyways I run a 9070xt. The gpu sampling switches back to the host when using Rocm cus line 665 only checks for cuda. If you add lookups for rocm and Musa you can get it to work and It gave me around 11% of a performance improvement. |
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looks like self promoting a paid service https://diffrun.dev/production-guide/ |
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@rhjdvsgsgks thanks, hidden. |
Integriert DiffusionGemma (block text-diffusion MoE auf Gemma-4 Backbone) als monolithischen Port, da unser Fork die upstream llama_model_base- Hierarchie (Commit 994118a, 2026-05-04) noch nicht hat. Geaendert: - llama-arch.h/.cpp: LLM_ARCH_DIFFUSION_GEMMA, 5 neue Tensor-Typen, 7 Diffusion-KV-Keys (canvas_length, eb_*) - llama-model.h: Diffusion-spezifische Felder (canvas_length, sc_*, pkv_*) - llama-model.cpp: 4 Cases fuer load_hparams, load_tensors, build_graph, type_name Mapping - llama-model-loader.cpp: Template-Instanziierung get_key<int64_t> - include/llama.h: C-API Erweiterungen (diffusion_set_sc, set_phase) - models.h: Forward declaration llm_build_diffusion_gemma - gemma4-common.h: llm_graph_qkv Helper-Struct - diffusion-gemma.cpp: Monolithischer Graph-Builder (547 Zeilen) - tools/diffusion-cli: Minimales CLI-Tool fuer Tests - common/arg.cpp + common.h: CLI-Flags fuer Diffusion-Parameter - gguf-py: DiffusionGemma Arch/Tensor/KV-Mappings - tests/test-llama-archs.cpp: Arch in Skip-Listen eingetragen Neu (aus PR ggml-org#24423, unveraendert uebernommen): - conversion/diffusion_gemma.py: HF->GGUF Konvertierung - ggml-cuda/diffusion-sampling.cu: CUDA-Kernels fuer Diffusion-Sampling - pocs/: Dokumentation (Entscheidung, Masterplan, Status) Getestet: - Build erfolgreich (libllama.so, llama-server, llama-cli, llama-diffusion-cli) - Modell-Loading: Q4_K_M laeuft (25.25B Parameter) - Inferenz: Einzelner Forward-Pass mit greedy decode - GPU-Offloading: 8 Layers auf RTX 3070 Laptop (~2.5 t/s) Offen: - Echter Diffusion-Decoding-Loop (Prefill -> bidirektionaler Decode x N) - Entropy-bound Decoder - Visual Diffusion Mode - Upstream-Tools (diffusion-gemma-eval, -server) bauen nicht
Portiert aus PR ggml-org#24423 (Unsloth). Der Entropy-Bound Decoder ist der Kern-Algorithmus von DiffusionGemma: - Canvas mit zufaelligen Tokens initialisiert - Pro Step: Argmax, Entropie, Multinomial-Sample pro Position - Acceptance nach Entropie-Bound (niedrigste zuerst) - Renoising: nicht-akzeptierte Positionen -> frisches Rauschen - Output = Argmax-Canvas (nicht gesampelte Tokens) - Lineare Temperatur-Schedule (t_max -> t_min) - Konvergenz: Stabilitaet + Konfidenz Technisch funktionsfaehig. Output-Qualitaet verbesserbar durch: - Self-Conditioning (SC-Tensoren fehlen noch) - Mehr Steps (20 getestet, 48 empfohlen) - Chat-Template Prompt-Formatierung
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It's so over for the GPU poor |
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Looks like all checks passed, when is this getting merged? |
…— coherence Reconciled DiffusionGemma-26B against llama.cpp's from-scratch GGML `diffusion-gemma` graph (ggml-org/llama.cpp#24423), used as a version-independent fp oracle to sidestep the transformers/diffusers dev-version bug that makes the released Python reference emit garbage logits (256 '.' then NaN). llama.cpp generates COHERENT text from the same Unsloth Q8_0 checkpoint ("The capital of France is Paris.", 7 entropy-bound steps), proving the checkpoint is fine and the released libs were the whole problem. Root cause of fni8's incoherence: the forward flattened the model's REGION-AWARE encoder-decoder structure into a uniform decoder-only pass, wrong in 3 load-bearing ways (confirmed against the reference graph + the real HF weight names): 1. input embedding — prompt rows must be the RAW scaled embedding (encoder pass); only canvas rows get self-conditioning + weightless post-norm (decoder pass). Old code post-normed all rows. 2. per-layer scalar — prompt rows use the ENCODER scalar (`model.encoder.language_model.layers.{i}.layer_scalar`), canvas rows the decoder scalar. Old code applied the decoder scalar everywhere and never loaded the encoder scalar (the converter dropped it with `model.encoder.*`). 3. attention mask — prompt queries are causal-over-prompt-only (never attend the canvas); canvas queries are bidirectional over prompt+canvas (SWA-clipped on sliding layers). Old code was fully bidirectional, so the prompt attended the canvas — corrupting the very context the canvas denoises against. Fix: thread the canvas boundary (P = S - canvas_len) through the forward; apply region-aware embedding, per-layer scalar, and attention mask; retain the encoder per-layer scalar in the converter (promoted to `.enc_layer_scalar`). All changes are backward-compatible: with no split, or a pre-fix `.fni8` lacking the encoder scalar, behaviour falls back to the previous uniform path. Tests (real V100, int8 dp4a): 9 passed. New `test_diffusion_region_aware_prompt_ independent_of_canvas` asserts the encoder region is causal-independent of the canvas (0.0 delta) while the canvas depends on both — the old path leaked canvas into the prompt region (max delta 2.08e-2). Adds `tools/reconcile_diffusion_gemma.py` (the llama.cpp final-logit oracle harness) for the real-weight numeric gate. Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_019VoDhxVLE7T7sjiwHfv34M
Worked on prelim Diffusion Gemma support!
llama-cliviallama-diffusion-cli -cnv -n 2048llama-diffusion-cli -cnv -n 2048 --diffusion-visualTo try this PR:
git clone https://github.com/ggml-org/llama.cpp cd llama.cpp gh pr checkout 24423 cmake -B build -DGGML_CUDA=ON cmake --build build -j --config Release --target llama-diffusion-clithen use a GGUF (any can work but for eg)
then use chat or visualization:
or
Example below (a bit blurry to limit to 10MB on Github :()

Disclaimer Heavy usage of AI, but verified logits matching with transformers, checked FP16 vs FP32 KV cache, long context checks and much more