61ff738177
find_slot places a sequence's tokens at permuted non-contiguous blocks; greedy generation is token-identical to stock (verified on Qwen3-0.6B at the pin), branch confirmed firing. Default off. The placement substrate for the gather-read. Assisted-by: Claude:opus-4.8 [Claude Code] Signed-off-by: Ettore Di Giacinto <mudler@localai.io>
llama.cpp patch series — paged attention (vLLM-parity engine)
A stacking series: each patch is a small, self-contained, independently-buildable step toward an
in-model paged-attention engine. They apply in numeric order on top of the pinned LLAMA_VERSION
(backend/cpp/llama-cpp/Makefile). The build applies them automatically after checkout (see the
llama.cpp: target). Keeping the work as ordered patches — rather than one big diff — is what lets us
rebase cleanly across llama.cpp bumps and avoid drift: when a patch stops applying, only that small
patch needs fixing, and the failure points at exactly which step the upstream change touched.
Base
LLAMA_VERSIONpin in../Makefile. All patches are generated against that exact commit. Bumping the pin = re-run the regen workflow below and fix only the patches that no longer apply.
The series (phases → patches)
| # | Patch | What | Verifies |
|---|---|---|---|
| 0001 | 0001-vendor-paged-kv-manager.patch |
Add src/paged-kv-manager.{h,cpp} (vLLM-parity block manager, CPU foundation) + CMake; no behavior change |
builds; unit-tested separately under ../paged/ |
| 0002 | 0002-paged-kv-storage.patch |
Shared block-pool KV tensor + set_rows-by-slot writes, behind LLAMA_KV_PAGED |
builds; write/gather round-trip |
| 0003 | 0003-paged-gather-read.patch |
build_attn_paged gather-read in llama-graph.cpp |
Gate 0: token-identical greedy gen, single + multi-seq |
| 0004 | 0004-paged-ondemand-alloc.patch |
On-demand block allocation via PagedKVManager | max concurrent seqs before OOM |
| 0005 | 0005-paged-continuous-batching.patch |
Block-granular admit/evict in the server slot path | tok/s vs concurrency, mixed-length |
| 0006 | 0006-paged-prefix-caching.patch |
Block-hash cross-request prefix dedup | TTFT + memory on shared prefixes |
Each row is a separate git commit on the dev branch (below), exported 1:1 as a patch. Default off
(LLAMA_KV_PAGED) until Gate 0 (0003) is green, so partial series never changes stock behavior.
Regen workflow (the anti-drift recipe)
# 1. check out the exact pin into a dev tree
git -C /tmp clone https://github.com/ggml-org/llama.cpp llama-dev && cd /tmp/llama-dev
git checkout <LLAMA_VERSION from ../Makefile>
git checkout -b paged
# 2. apply the current series (each becomes a commit), or develop the next patch
git am /path/to/backend/cpp/llama-cpp/patches/00*.patch # or `git apply` + commit per patch
# 3. iterate a phase as ONE commit, then export the whole series 1:1
git format-patch <LLAMA_VERSION>..paged -o /path/to/backend/cpp/llama-cpp/patches/ --zero-commit -N
# 4. on a pin bump: rebase `paged` onto the new pin; only conflicting patches need edits; re-export.
Build integration
../Makefile's llama.cpp: target runs, after git checkout -b build $(LLAMA_VERSION):
for p in $(CURRENT_MAKEFILE_DIR)/patches/0*.patch; do git apply --verbose "$p"; done
All variants (avx/avx2/avx512/cuda/…) copy the patched llama.cpp/ tree, so the series ships everywhere.
Status
0001 in progress. The CPU foundation (the block manager + ggml write/gather + attention numerics) is
already built and verified under ../paged/ (paged_kv_manager.*, tests, README.md); these patches
vendor it into the llama.cpp tree and wire it in-model phase by phase.