Files
ik_llama.cpp/examples/quantize
Andrew Chan 25d34e3d2f Trellis quants with CPU inference (#441)
* WIP

* WIP

* WIP

* Testing Trellis quantization

Using 12 bits per 8 weights I get a better rmse than
iq2_xxs. I still need to see how quantizing the group-of-8
scales will affect accuracy. By AVX2 SIMDifying the search
for the best code, LLaMA-3.1-8B gets quantized in 130 seconds
on the Ryzen-7950X CPU - sluggish but still acceptable.

* Testing Trellis quantization: 4-bit quantized block scales

rmse increases by just 3%, so this is beating iq2_xss in terms
of rmse at the same 2.0625 bpw.

* Testing Trellis quantization: playing with scales and generators

* iq2_kt: quantize / dequantize

I now see that I was comparing apples to oranges:
iq2_xxs was using a weight of sigma^2/4 + x^2, while
the Trellis approach wasn't (weight = 1). Once I use the same weight,
iq2_kt is actually slightly worse than iq2_xxs in terms
of rmse, so does not look promising at this point.
Also, once each group of 8 Trellis values no longer has a
constant sum(q^2) that we can precompute, quantization
becomes significantly slower (476 seconds for LLaMA-3.1-8B).

* iq2_kt: CUDA dequantize

so we can run perplexity calcs.
As already indicated by rmse, the 2-bit trellis approach is
quite a bit worse than iq2_xxs.

* WIP

* WIP

* WIP - try larger blocks

With blocks of 32 and 16 bits per groups of 8 the brute force
seach becomes prohibitive in terms of CPU time (30+ minutes
for 8B LLaMA after SIMDifying with AVX2). The trick is to
group the points in clusters, find the nearest cluster,
and only search within the cluster.

* iq2_kt - this is better

Using blocks of 32 and 16 bits per group of 8 weights
it beats iq2_xxs in terms of PPL by a significant margin.
It is 0.0625 bpw larger, but even if we go to 15 bits per
group od 8 (so 0.0625 bpw less than iq2_xxs), PPL is still
lower.

* iq2_kt - even better

Re-quantize after determining block scales
(at the epxense of much longer quantization time).

* iq2_kt: CUDA dot product

Implemented as DMMV.
Very slow - just 81 t/s for LLaMA-3.1-8B.
Then again, Q2_K_S with forced to use DMMV only
gets 112 t/s vs 145 t/s via MMVQ. My memory is that
when the DMMV kernels were properly maintained/used,
DMMV was about on par with MMVQ for k-quants on my GPU.

* iq2_kt: very slightly faster CUDA dot product

* iq2_kt: f16 CUDA dot product

We arrive at 112 t/s.

* iq2_kt: faster f16 CUDA dot product

We arrive at 139 t/s (no FA), and 149 t/s (FA).

My RTX-4080 is ~20% slower than the RTX-6000 quoted in the
QTIP repository, so with FA (which I'm sure they also used)
we are at around ~180 t/s on their GPU, so almost matching
their performance.

* iq2_kt: faster f16 CUDA dot product

We arrive at 146 t/s (no FA), and 158 t/s (FA).
This is measured for LLaMA-3.1-8B with output.weight
left as f16.

* Minor

* Adding iq3_kt

3.125 bpw. So far does not look good on the PPL vs bpw plot.

* Forgotten change

* WIP

* WIP

* iq3_kt WIP: slowly improving

PPL(LLaMA-3.1-8B-Instruct, 8192) is now 6.8322, which is
starting to be competitive/slightly better than other quants.

* WIP

* iq3_kt WIP: slowly improving

PPL(LLaMA-3.1-8B-Instruct, 8192) is now 6.7892

* iq3_kt WIP: slowly improving

PPL(LLaMA-3.1-8B-Instruct, 8192) is now 6.7689 after shrinking
by 0.015 bpw by using iq4_k instead of q5_k for attn_v.

* iq3_kt WIP: speed up quantization

Nearly 60% improvement of quantization speed by having the
points nelonging to a cluster copied to contiguous memory
during initialization, and then accessed sequantially while
searching for the closest point. LLaMA-3.1-8B now gets
quantized in ~150 seconds on the Ryzen-5975WX.

* iq3_kt speed up quantization

Same trick as last commit applied to iq2_kt. Here we get
an even larger speedup: quantization time on the Ryzen-5975WX
for LLaMA-3.1-8B drops to 195 seconds from 375 seconds!

* iq3_kt: CUDA dot product

* iq2_kt: SOTA

We arrive at
PPL(LLaMA-3.1-8B-Instruct, 8192) = 9.2406
PPL(LLaMA-2-7B,            4096) = 6.4179

* iq2_kt: SOTA

We arrive at
PPL(LLaMA-3.1-8B-Instruct, 8192) = 9.1642
PPL(LLaMA-2-7B,            4096) = 6.3920

* Adding iq4_kt - not competitive at this point

* WIP

* WIP

* iq4_kt: CUDA dot product

* iq4_kt: minor tweaks

* iq2_kt: SOTA

We arrive at
PPL(LLaMA-3.1-8B-Instruct, 8192) = 9.1642
PPL(LLaMA-2-7B,            4096) = 6.3920

* iq2_kt: SOTA

We arrive at
PPL(LLaMA-3.1-8B-Instruct, 8192) = 9.0297
PPL(LLaMA-2-7B,            4096) = 6.3913

Ah, quantization is faster too. About 20% faster.

* iq3_kt: small improvements and faster quantization

* iq2_kt: SOTA

We arrive at
PPL(LLaMA-3.1-8B-Instruct, 8192) = 8.9627
PPL(LLaMA-2-7B,            4096) = 6.3825

Quantization is faster too: ~200 seconds for LLaMA-3.1-8B
on Ryzen-5975WX.

* iq3_kt: small progress

* WIP

* iq4_kt: go to 4.0 bpw

15 bits per group of 4, plus 8 bit scales ifor blocks of 32.
This gives a slightly better PPL than iq4_kss.

* iq4_kt: very slightly better

at the expense of much longer quantization time.

* iq4_kt: failed attemt to adjust CUDA dot product

It was working for 4.125 bpw. But after changing to 4.0 bpw
there is something wrong and I don't see the bug.

* DRY

* DRY

* iq4_kt: CUDA dot product works

* DRY

* Report actual bpw

* Minor tweaks

* Checkpoint

Go to groups of 8 for iq3_kt. 2 x 8 = 16 bits for the magnitude
plus 1 bpw for the sign. It goves a visible improvement in the
PPL vs bpw plot, but that comes at the expense of much longer
quantization time (7.5 minutes for LLaMA-3.1-8B on the Ryzen-5975WX).

I also notices that the 3INST generator is not actually generating a
Gaussian distribution. But going to a better generator means
readjusting all the hyper-parameters, so leaving it for later.

* WIP for IQ2_KT

* WIP - working basic iq2_kt

* still super slow (0.17t/s eval)

* flatten 3inst iters + avx2 (0.3t/s eval)

* iq3_kt (0.3t/s eval) and renames

* wip buggy iq4_KT

* fix (0.22t/s eval)

* naming and remove unused fn

* cleanup

* more cleanup

* delete unused and noncompiling mmvq functions

* Some performance tweaks

* Slighty faster iq2_kt

* port Trellis struct to iq3_kt, iq4_kt

* oops untracked files

---------

Co-authored-by: Iwan Kawrakow <iwan.kawrakow@gmail.com>
2025-05-23 09:17:52 +03:00
..
2024-07-27 07:55:01 +02:00

quantize

You can also use the GGUF-my-repo space on Hugging Face to build your own quants without any setup.

Note: It is synced from llama.cpp main every 6 hours.

Example usage:

# obtain the official LLaMA model weights and place them in ./models
ls ./models
llama-2-7b tokenizer_checklist.chk tokenizer.model
# [Optional] for models using BPE tokenizers
ls ./models
<folder containing weights and tokenizer json> vocab.json
# [Optional] for PyTorch .bin models like Mistral-7B
ls ./models
<folder containing weights and tokenizer json>

# install Python dependencies
python3 -m pip install -r requirements.txt

# convert the model to ggml FP16 format
python3 convert_hf_to_gguf.py models/mymodel/

# quantize the model to 4-bits (using Q4_K_M method)
./llama-quantize ./models/mymodel/ggml-model-f16.gguf ./models/mymodel/ggml-model-Q4_K_M.gguf Q4_K_M

# update the gguf filetype to current version if older version is now unsupported
./llama-quantize ./models/mymodel/ggml-model-Q4_K_M.gguf ./models/mymodel/ggml-model-Q4_K_M-v2.gguf COPY

Run the quantized model:

# start inference on a gguf model
./llama-cli -m ./models/mymodel/ggml-model-Q4_K_M.gguf -n 128

When running the larger models, make sure you have enough disk space to store all the intermediate files.

Memory/Disk Requirements

As the models are currently fully loaded into memory, you will need adequate disk space to save them and sufficient RAM to load them. At the moment, memory and disk requirements are the same.

Model Original size Quantized size (Q4_0)
7B 13 GB 3.9 GB
13B 24 GB 7.8 GB
30B 60 GB 19.5 GB
65B 120 GB 38.5 GB

Quantization

Several quantization methods are supported. They differ in the resulting model disk size and inference speed.

(outdated)

Model Measure F16 Q4_0 Q4_1 Q5_0 Q5_1 Q8_0
7B perplexity 5.9066 6.1565 6.0912 5.9862 5.9481 5.9070
7B file size 13.0G 3.5G 3.9G 4.3G 4.7G 6.7G
7B ms/tok @ 4th 127 55 54 76 83 72
7B ms/tok @ 8th 122 43 45 52 56 67
7B bits/weight 16.0 4.5 5.0 5.5 6.0 8.5
13B perplexity 5.2543 5.3860 5.3608 5.2856 5.2706 5.2548
13B file size 25.0G 6.8G 7.6G 8.3G 9.1G 13G
13B ms/tok @ 4th - 103 105 148 160 131
13B ms/tok @ 8th - 73 82 98 105 128
13B bits/weight 16.0 4.5 5.0 5.5 6.0 8.5

Llama 2 7B

Quantization Bits per Weight (BPW)
Q2_K 3.35
Q3_K_S 3.50
Q3_K_M 3.91
Q3_K_L 4.27
Q4_K_S 4.58
Q4_K_M 4.84
Q5_K_S 5.52
Q5_K_M 5.68
Q6_K 6.56

Llama 2 13B

Quantization Bits per Weight (BPW)
Q2_K 3.34
Q3_K_S 3.48
Q3_K_M 3.89
Q3_K_L 4.26
Q4_K_S 4.56
Q4_K_M 4.83
Q5_K_S 5.51
Q5_K_M 5.67
Q6_K 6.56

Llama 2 70B

Quantization Bits per Weight (BPW)
Q2_K 3.40
Q3_K_S 3.47
Q3_K_M 3.85
Q3_K_L 4.19
Q4_K_S 4.53
Q4_K_M 4.80
Q5_K_S 5.50
Q5_K_M 5.65
Q6_K 6.56