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glm5next: avoid soft_max gridDim.y overflow in the indexer - #28729

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AIalliAI:fix/glm5next-kpool-softmax-grid-y
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glm5next: avoid soft_max gridDim.y overflow in the indexer#28729
AIalliAI wants to merge 45 commits into
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AIalliAI:fix/glm5next-kpool-softmax-grid-y

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Overview

Reshape k-pool indexer gate logits before ggml_soft_max so n_new_max does not map to gridDim.y, which is capped at 65535 on CUDA. During k-pool rebuild at long context (n_kv >= 262144, kpool = 4), n_new_max reaches 65538 and the launch aborts with SOFT_MAX failed.

Fold n_new_max and n_stream into ne1 via ggml_reshape_2d, then reshape back to 4D for downstream mul / sum_rows. Same pattern as qwen4exp.cpp.

Depends on #27754. Review the scoped 2-commit diff here:
unslothai:glm5next/upstream...AIalliAI:fix/glm5next-kpool-softmax-grid-y

Intended merge path: unslothai#214 into glm5next/upstream, then #27754 to master. Do not merge this PR directly to master.

Additional information

Related: #27773, timkhronos#11, #27901

Fork copies: unslothai#214, AIalliAI#1

Requirements

  • I have read and agree with the contributing guidelines
  • AI usage disclosure: YES - assisted implementation and review; I understand the change and can maintain it.

danielhanchen and others added 30 commits August 26, 2026 16:48
Metadata and tensor loading only. The graph entry point throws, as qwen4exp
did at the same stage.

kda.gate_lower_bound is read as required: kimi-k3 selects the softplus branch
when it is absent, which is a different function rather than a missing clamp.

The absorbed MLA projections are 3D, so glm5next joins bailingmoe3 in the MXFP4
carve-out that would otherwise quantize them as expert tensors.
glm5next's mHC is DeepSeek-V4's hyper-connection block: same wide residual,
same 24-row mixer split, same two activations, same Sinkhorn. Only the final
collapse differs, so the graph derives from llama_model_deepseek4::graph and
reuses build_hc_pre / build_hc_post / build_hc_sinkhorn rather than restating
them, as graph_dsv4 already does in dflash.cpp.

dsv4_hc_mean becomes a static member so both archs can reach it; the body and
both deepseek4 call sites are otherwise untouched. The generated code for
deepseek4 is unchanged apart from the endbr64 landing pad the helper now needs
as a global symbol.

The four streams start as exact copies of the token embedding and collapse to
an unweighted mean after the last layer: this checkpoint has no hc_head.

KDA, DSA and the MoE land in later commits, so the two sublayers throw. The
mHC wiring around them is final.
Copy-adapts kimi-k3's KDA layer rather than kimi-linear's or bailingmoe3's: it
already matches on the recurrence ordering, the bounded-sigmoid decay gate and
its branch selection, dt_bias added per channel before the reshape, per-head A
broadcast, SiLU after the conv, f/g/beta read from the pre-convolution hidden
states, and the gated output RMSNorm with a plain weight.

Three differences from kimi-k3. The output gate is low rank, g_b(g_a(x)) as in
kimi-linear, which is what PR 1's converter emits. The q/k L2 eps is a literal
1e-6, the reference's own constant, not f_norm_rms_eps; ggml_l2_norm implements
max(sqrt(sum), eps) rather than sqrt(sum + eps), which at head_dim 128 differs
by about eps/(2*sum) and never trips the clamp, so it is close but not
bit-exact. And the cross-layer residual, latent MoE, situ activation and MLA
output gate have no counterpart here.

The conv follows the reference and convolves q|k|v as one depthwise kernel,
which keeps the conv state a single contiguous block so build_conv_state can
snapshot it. That plus build_recurrent_attn is what makes the layer safe under
recurrent-state rollback, so the arch joins llm_arch_supports_rs_rollback;
without that entry the guard in llama_context silently clamps n_rs_seq to 0.

build_delta_net_autoregressive reshaped a per-channel KDA gate onto ne1, but ne0
is the key axis everywhere else in that function, so it decayed along the value
axis. Invisible for GDN, where the gate is scalar and both spellings produce the
same [1, 1, H_v, n_seqs], and invisible to the shape checks because S_k == S_v.
Fixed rather than asserted around, since glm5next reaches that path on any
backend without the fused operator.

llama_model_deepseek4::graph now derives from llm_build_delta_net_base so
glm5next, which derives from it for the mHC residual, can reach build_delta_net.
The base is a method-only mixin over llm_graph_context with no data members and
no virtuals beyond the destructor llm_graph_context already has; deepseek4.cpp,
dflash.cpp and kimi-k3.cpp compile to byte-identical instructions across the
change.

graph_max_nodes moves the arch to kimi-k3's tier. Measured on the Tiny fixture
with the chunked fallback: 182 nodes plus 15/16 per token for each KDA layer and
46 per layer for the mHC mixers, so the 45-layer model needs 8.3k + 31.9 per
token before DSA or the MoE are counted, which overruns the n_tokens*40 budget.

test-llama-archs synthesised no MLA, hyper-connection, kpool or expert-weight
keys for glm5next, so PR 1's required get_key calls threw out of the sweep and
truncated it at 75 of 143 architectures. The fixture is complete now and the row
is skipped explicitly while the DSA and feed-forward sublayers still throw.
The routing is DeepSeek-V3 noaux_tc exactly as build_moe_ffn already implements
it: sigmoid scores, exp_probs_b added for the top-k SELECTION only, weights
gathered from the unbiased scores, normalised, then scaled by
routed_scaling_factor. n_group and topk_group are both 1, so the group-limited
stage is degenerate and build_moe_ffn's n_expert_groups > 1 guard skips it; no
group keys are written and none are needed.

The clamp is the one thing that needed a change outside this arch. glm5next
clamps the gate max-only and the up symmetrically, both BEFORE the SiLU, which
is what the branch behind the DEEPSEEK4/DFLASH arch gate already does; the else
branch clamps after the SiLU and is a different function. Adding the arch to
both gates reuses it rather than restating it. The two conditions are separate
because the dense path and the MoE path read different hparams arrays.

The leading dense layers clamp too. The reference builds them from the same
Glm5NextTextMLP as the shared expert, so swiglu_limit is not MoE-only, and the
converter already writes swiglu_clamp_shexp for every layer rather than only the
sparse ones. The shared expert is added unscaled.
nope-only MLA in the absorbed form, over every cached position. below
index_topk + index_kpool - 1 resident tokens the indexer selects all of them,
so this is exactly what the sparse path degenerates to, and it is a reference
the sparse commit can be checked against.

the attention half of the hybrid memory becomes the K-only variant: after
absorption the cache holds the kv_lora_rank latent and V is a view of K.
both are required keys for glm5next, so a model saved without them cannot be
loaded back. this is what stops test-llama-archs from round-tripping the arch.
the DSA sublayer no longer throws, so the arch can construct and run. it needs
the MLA head shape as well: with n_head_kv taken from the per-layer array it
would size the K cache row n_head times wider than the latent the graph writes.
index_topk + index_kpool - 1 is the number of positions the indexer keeps, and it
is what makes the dense attention this branch builds exactly equal to the sparse
path below that many cached tokens. an off-by-one in it is invisible to every
output comparison measured so far, on both a dense and a sparse fixture, so it is
checked against a second spelling of the same arithmetic instead.
The DSA layers of this model score pools of index_kpool consecutive positions
rather than single keys, and the pooled key cannot be rebuilt from the MLA
latents. llama_memory_hybrid therefore gains an optional third cache holding one
indexer key and one compressor gate per token, so the hybrid carries the KDA
conv+recurrent state, the MLA latents and the indexer keys at once.

Absent unless filter_idx is given, which defaults to null, so every existing
architecture gets exactly what it got before, state file layout included.

Two heads per cell, not one. GLM's compressor is not a mean pool: it is a
per-channel softmax over the kpool slots with logits gate + ape, where the gate
is a second projection of the hidden state of width indexer_head_size. Caching
it beside the key is the only way a pool survives its member tokens leaving the
batch. Architectures with indexer_kpool == 0 still get one head.

The indexer cache is handed the attention cache's slot layout rather than
finding its own, so the two agree cell for cell, and apply() asserts they do.
It also keeps its own dtype: -ctk q8_0 would otherwise quantise the gates, which
feed a softmax.

llama-kv-cache-kpool.{h,cpp} builds the pool <-> cell map host side. Pools are
defined on positions and cells are whatever find_slot handed out, so the
correspondence cannot be derived in the graph. Nothing here emits a negative
index: ggml_set_rows asserts i1 >= 0, so unpopulated entries are clamped into
range and neutralised by an additive -INFINITY instead.

Two things the map does that the qwen4exp shape it is ported from does not:

  - the top-k budget is indexer_top_k exactly, with the always-selected tail
    biased to -INFINITY so it spends none of it, and forced back in through a
    host-built base mask for the scatter. indexer_top_k is a whole number of
    pools, so the cut lands on a pool boundary; the reference's own output width
    of indexer_top_k + kpool - 1 does not, and ggml_top_k is unordered among
    equals on both CPU and CUDA.
  - one map per ubatch, shared by every indexer layer, since nothing in it
    depends on the layer. Measured on a 16 Ki cell cache with 512 tokens:
    ~4 ms once against ~4 ms x n_layers.

A unified cache with more than one sequence would let two sequences at the same
position pool each other's keys, so create_memory refuses it up front rather
than aborting mid-run.

tests/test-glm5next-memory.cpp: 74 checks, 0 failures, on both the full and the
trunk-only fixture. test-llama-archs is byte identical to the same build without
this commit at a fixed seed: 452 rows, 0 FAIL. Session state files for
qwen3next, falcon-h1, minimax-01, qwen35moe and a real Falcon-H1-0.5B are byte
identical too, across write, reload and rewrite.
Builds the pooled lightning indexer and gives the DSA layers a sparse attention
path driven by it.

Top-k runs over the POOL axis at select_k = index_topk/index_kpool, and the
selected pools are expanded to their member cells through pool_cells. That is
the reference's own two-step (modular_glm5_next.py, Glm5NextTextIndexer.forward:
topk over the pool axis, then selected_indices = pool_indices[batch_idx,
selected]), and it is not interchangeable with a single top-k of width
index_topk over member cells. The argument for the cell-level form - a pool's
members carry its score bit-exactly, so the cut must land on a pool boundary -
assumes tie groups never span pools. They do: ReLU drives most pool scores to
exactly 0.0, and ggml_top_k is explicitly unordered among equals, so the cut
falls inside an inter-pool tie group and splits a pool. Measured on TinySparse
at 512 tokens, the cell-level form leaves a partial pool on 7.51% of query rows
at layer 3 and 5.93% at layer 7; this form leaves none.

The indexer key and gate STORE is unconditional; only the SCORING is gated, on
n_ctx > index_topk + index_kpool - 1. Gating the store the same way would leave
every cell written below n_select with no indexer state, and the first ubatch to
cross n_select would pool cells that were never written.

Nothing here changes any other architecture: test-llama-archs produces a table
byte-identical to the parent's, 300 rows over 143 archs, 0 FAIL.
The tower is the GLM-OCR ViT with a clamped SwiGLU: the gate is bounded
above only, the up projection on both sides, and both before the SiLU.
ggml_swiglu_oai clamps the same way but then adds one to the up branch,
which is a gpt-oss detail this model does not share, so this adds an
FFN_SILU_CLAMP op rather than reusing it.

The clamp sits at the per-block MLP and again at the merger. Both read
hparams.ffn_op, so the graph body stays the GLM-4V one and the pair is
covered together.

It gets its own projector type rather than a flag on glm4v because the
image token limits differ (16/8000 against 8/4096, per the GLM-5.3-Flash
preprocessor) and those are hardcoded per projector, and because the
clamp must stay off for GLM-4V and GLM-OCR.

Also writes clip.vision.spatial_merge_size. No GLM4V-family mmproj has
ever carried it: Glm4VVisionModel skips the Qwen3VL parameters, which is
where it is written, so clip.cpp's hardcoded 2 has been carrying it.

Images only. glm5next spells video with its own token pair and distinct
start/end spans, and that is not handled here.
the vision tower shipped with the shared dynamic-size preprocessor, which is a
qwen-style smart_resize. the 2026-08-26 GLM-5-Next adaptation resizes
differently: both edges are aligned up by ceil rather than round, an over-budget
image is fitted by binary searching the content height for the largest aligned
canvas still within max_pixels, and the resized content is pasted into the
top-left of that canvas rather than centred and stretched to fill it. an image
already at or above min_pixels is never upscaled.

min_pixels/max_pixels stay in tokens. the reference scales them by
temporal_factor * factor**2 and compares against aligned_frames * area, and
aligned_frames equals temporal_factor for a still image, so the two cancel and
hparams.image_min_pixels / image_max_pixels (16 and 8000 tokens, 12544 and
6272000 pixels) are used directly.

glm4v and glm-ocr keep the dynamic-size preprocessor.

images only. video has its own token pair (154855, distinct from the image
token 154854) with its own start/end spans, and is out of scope here.

the resize arithmetic is covered in test-mtmd-impl against values taken from the
reference processor, including the 16- and 8000-token boundaries, extreme aspect
ratios, and inputs where the binary search and smart_resize disagree.
glm4 / chatglm-bpe tokenizer.json files set "ignore_merges": true, meaning a
pre-token that is already a vocab entry is emitted directly and the merge loop
never runs. llama.cpp implements this (llama-vocab.cpp, the get_ignore_merges()
short-circuit) but only enables it for a hardcoded list of pre-tokenizer names,
and glm4 was never added.

Without it the merges are applied - correctly - and reach a different answer,
because greedy BPE cannot always reconstruct a vocab entry from its bytes.
" 王" (Ġçİĭ, id 102322) is the case that exposed it: from Ġ ç İ ĭ the only
merges available are (Ġ,ç)=27944, (ç,İ)=76417 and (çİ,ĭ)=239209, so the lowest
rank wins first and yields Ġç İ ĭ, at which point neither (Ġç,İ) nor (İ,ĭ)
exists and it stops three tokens short. Reaching Ġçİĭ needs (Ġ,çİĭ) at 242943,
which requires never taking (Ġ,ç) at 27944.

The trigger is whitespace immediately before a CJK character, so pure Chinese
prose is unaffected and mixed Chinese-English is not:

  pure Chinese prose        620 vs 620 tokens, already identical
  mixed Chinese-English     680 -> 600 tokens, now identical to HF (-13.3%)
  wikitext-2 (289569 tok)   one divergence -> byte-identical

Found while comparing GLM-5.3-Flash perplexity against transformers, vLLM and
SGLang: the mismatch bounded how many scoring windows could be compared at long
context, and reads exactly like a model-port defect rather than a tokenizer one.
The scripted resolution used for the rebase mangled four files: it spliced a
condition into the middle of graph_max_nodes' multi-line else-if, dropped the
mtmd_image_preprocessor_glm5next declaration, dropped llama-kv-cache-kpool.cpp
from src/CMakeLists.txt (undefined llama_kpool_* and the llm_graph_input_kpool
vtable at link time), and left an "} else {" immediately followed by an
"} else if" in test-llama-archs.

These files are byte-identical between this base and the tree the glm5next
work was verified on, so each is taken from there verbatim.
deepseek4 sets n_embd_out_impl to hc_mult*n_embd to size its MTP h input.
glm5next inherited that, but our t_embd is build_norm(build_hc_mean(...)),
which is [n_embd, n_tokens]. n_embd_out() therefore reported 4*n_embd while
the tensor held n_embd, and llama-context read n_outputs*n_embd_out floats
out of it, four times what is there.

The assert at that site sizes the destination buffer, so nothing catches the
short source. Only --embeddings and llama_get_embeddings* reach the path,
which is why plain generation never showed it.

Note for when the NextN graph starts consuming h: give MTP its own width
rather than widening n_embd_out again.
The mHC residual mixers, the lightning indexer (selection gate, learned
k-pool position table, and the three indexer projections) and the KDA
recurrence gates are about 1 GiB in total on GLM-5.3-Flash, so the size cost
is noise against a 100-240 GB quant. Quantizing them perturbs which pools
the indexer selects and how much state each KDA step retains, and those
errors compound along a sequence rather than averaging out.

Both spellings are required. The compressor tensors arrived with the
DeepSeek-V4 merge and use an underscore (indexer_compressor_ape / _gate),
while the projections use a dot (indexer.proj / .attn_k / .attn_q_b), so a
single "indexer." prefix test silently misses the compressor pair.

attn_q_a, attn_kv_a_mqa, attn_k_b and attn_v_b are deliberately not listed.
They are precision sensitive too, but the release recipe pins them to q8_0
via --tensor-type, and that is the configuration the shipped quants were
measured in.

Verified with llama-quantize --dry-run q4_k_m on the BF16: all 12 pinned
families report 0 quantized (45 mHC, 12 indexer, 34 KDA each), while
ffn_gate_exps 43/43, attn_q_a 12/12 and attn_output 46/46 still quantize.
The 101-line glm5next block was dropped from test-mtmd-impl.cpp when the
vision work was rebased, even though the commit message still claimed the
resize arithmetic was covered there. It holds the 36-case table over the
16- and 8000-token budget boundaries, including six cases annotated as ones
where a naive smart_resize disagrees, so it is the guard against sliding
back to stretch-to-fill instead of ceil-align plus zero pad.

Restored from 29c096371. test-mtmd-impl now runs 216 assertions, of which
glm5next_resize contributes 185.
add_vision_swiglu_limit was inserted directly above the next method with no
blank line between them, which flake8 flags as E301. Caught by ggml-org CI.
llama-embedding turns -np 1 into kv_unified with n_seq_max 256, so every
--embeddings run hit the refusal in create_memory and llama-embedding then
dereferenced the null context. Two fixes.

The pool map is now per SEQUENCE rather than per stream. A non-unified cache
already gives one sequence per stream, so nothing changes there. A unified
cache puts every sequence of the ubatch in stream 0, and the stream's pool
table is cut into one contiguous run per sequence, each rebased on its own
lowest resident pool. pool_bias is -INFINITY outside the query's own run, so a
query never spends budget on a foreign pool, and cand_mask already kept foreign
cells out of the attention mask.

Packed runs, not one full-width table per sequence: the indexer scores every
pool slot against every query, so a full-width table per sequence multiplies
the score tensor by the sequence count and graph_reserve asked for 286 GB at
n_seq_max 256. The table is n_kv/kpool shared plus 2 slots per sequence for
rebasing, which is exact while the sequences' cells are disjoint. A prefix
shared through seq_cp can oversubscribe it, and then a sequence keeps its
newest pools -- the same cut a large hole in the cache already forces.

The top-k stays over POOLS and pool_cells still holds whole pools, so pool
integrity is untouched.

examples/embedding also checked only the model for null, not the context.
test-glm5next-memory asserted that create_memory REFUSES -kvu with n_seq_max 2,
which was the contract before the pool map became per sequence. Assert the new
one: the cache is built, and one ubatch holding both sequences is driven through
llama_kv_cache_set_input_kpool.

Three checks replace the guard. llama_kpool_n_pools is n_kv/kpool plus 2 slots
per sequence, so the table is a shared budget and not one full-width table each.
Every pool a query may spend budget on holds only that query's own visible cells
-- the invariant a shared cells array breaks if the map is keyed per stream. The
two sequences get disjoint runs and neither run is empty.

Both cell-level checks fail if the runs are made to overlap, so they are not
tautologies. cell_pool is not requested here: it has one row per stream and a
cell that two sequences share has nowhere to put its second pool.
sel_mask and cand_mask are KQ-mask shaped and hold only 0.0f and -INFINITY,
both exact in f16, so storing them in half the bytes is lossless. At
n_ctx = 1 Mi, n_ubatch = 512 that is 2 GiB saved per mask plus 1 GiB on the
per-layer ggml_dup.

ggml_add gives its result src0's type and f16 + f32 -> f16 is a supported
bin_bcast on CUDA and on the CPU, so the f16 selection mask absorbs the f32
KQ mask that flash-attention-off builds, and ggml_soft_max_ext takes an f16
mask as readily as an f32 one. Under flash attention the KQ mask is already
f16 and the per-layer ggml_cast disappears.

llama_kv_cache_set_input_kpool now writes either width and asserts the two
masks share a type instead of asserting f32.
Replaces the 7-node score chain (mul_mat, cont/permute, relu, mul,
sum_rows, cont/permute, add) with one ggml_lightning_indexer, as
glm-dsa, deepseek4, deepseek32 and dots3note already do. The op needs an
f16 mask, so pool_bias is cast once per graph in build_inp_kpool rather
than once per DSA layer.

pool_k is left in f32 so the CUDA op takes its f32 vector path, not the
f16 wmma path, which would undo the GGML_PREC_F32 on the head weights.

The unfused chain stays behind cparams.fused_lid, plus a
LLAMA_FUSED_LID_DISABLE escape hatch.
Deletes comments that restate the code, section banners, paragraph spacers,
pointers, development narration and measured numbers that belong in the PR
description. What survives is limited to correctness constraints, reference
implementation citations, warnings that a tempting alternative is wrong, and
explanations of real bugs - each stated in one or two lines.

Comments only: verified by stripping every comment from each file and comparing
the normalised source against the pre-pass baseline.
danielhanchen and others added 15 commits August 28, 2026 02:43
# Conflicts:
#	gguf-py/gguf/tensor_mapping.py
#	src/llama-model.cpp
seq_add only skipped the pooled-key rebuild when the shift itself was a
multiple of kpool. That is not sufficient: a pool straddling p0 or p1 keeps
some members and moves the rest, so it is regrouped no matter how the shift
is aligned, and its cached pooled key goes stale while still looking complete.

Both callers pass an arbitrary bound. The server's context shift uses
n_keep + n_discard and its prompt-cache reuse uses the match head, so this is
reachable in normal use: with --keep 39 and n_ctx 8192, n_discard is 4076 and
p0 is 4115, which is a multiple-of-4 shift starting mid-pool.

Also require both bounds to be pool-aligned. A negative p0 or p1 means "from
the start" / "to the end", which no pool can straddle.
Second reduction pass over the arch's comments: 405 comment lines on the
branch's own added lines down to 234, no code changes.

Deletes rather than reshortens. What stayed is limited to things whose absence
would let a reader make a specific mistake: reference constants and sign
conventions, the ordering and precision constraints the graph relies on, and
the shapes of ggml tensors, whose type carries none.
ggml_mul_mat_set_prec was deprecated upstream in ggml-org#26675 and the macOS
prebuilt legs build with fatal warnings, so the mix stopped compiling
there. Same op_params slot, same F32 accumulation.
@github-actions github-actions Bot added model Model specific testing Everything test related mtmd Related to multimodal functionality (video/image/audio) conversion labels Sep 11, 2026
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Hi @AIalliAI, thanks for your contribution!

Per our contribution guidelines, the automated PR checker found the following issue(s) that need your attention:

  • Multiple open PRs from a new contributor: We limit new contributors (those without a previously merged PR) to 1 open PR at a time. You currently have 2 open PRs.

  • Large PR: Large changes require prior discussion (e.g. an issue or RFC) and maintainers may not be able to review this PR as-is. Consider splitting it into smaller, focused PRs.


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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Hi @AIalliAI, thanks for your contribution!

Per our contribution guidelines, the automated PR checker found the following issue(s) that need your attention:

  • Multiple open PRs from a new contributor: We limit new contributors (those without a previously merged PR) to 1 open PR at a time. You currently have 2 open PRs.
  • Large PR: Large changes require prior discussion (e.g. an issue or RFC) and maintainers may not be able to review this PR as-is. Consider splitting it into smaller, focused PRs.

Please note that maintainers reserve the right to make final decisions on PRs. If you believe there is a mistake, please comment below.

This makes no sense, I'm tired of waiting weeks and weeks for glm5flas support, first you tag me and say dont make big pr's then you say make multiple small, then you say I'm limited to one.
Hereby I'm informing you that i will make only one big one! Only focused on fully supporting glm5 models. I've managed to get them running on my machine. @maintainers

@AIalliAI AIalliAI closed this Sep 11, 2026
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