Qualcomm AI Engine Direct - Enable Lookahead Decoding

[shewu-quic]

Summary:

• Add new eval_mode: lookahead
• Add three arguments: ngram, window, gcap
• Add lhd_token_generator

Command

python3 examples/qualcomm/oss_scripts/llama/llama.py -b build-android --checkpoint stories110M.pt --params params.json --tokenizer_model tokenizer.model --prompt "Once" --temperature 0 --tokenizer_bin tokenizer.bin --llama_model stories110m --model_mode lookahead --ptq 16a4w -m SM8650 -H ${host} -s ${device}  -a ${artifacts} --max_seq_len 4096 --kv_updater smart_mask  --prefill_ar_len 64 --ngram 3 --window 2 --gcap 2

Test Results

QNN SDK: 2.28
Device: SM8650
max_seq_len: 4096

Performance Improvement under different AR-N and different W/G/N

Llama 3.2 3B

Llama 3.2 1B

Story Llama 110M

Performance Improvement under different prompt

Reference

• https://lmsys.org/blog/2023-11-21-lookahead-decoding/
• https://github.com/hao-ai-lab/LookaheadDecoding/tree/main/lade
• https://github.com/ggml-org/llama.cpp/blob/master/examples/lookahead/lookahead.cpp

cc: @haowhsu-quic

[pytorch-bot]

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❌ 1 New Failure, 2 Unrelated Failures

As of commit 1bc9dcb with merge base aed9c7e ():

NEW FAILURE - The following job has failed:

• pull / android / run-emulator (gh)
  The process '/usr/bin/sh' failed with exit code 255

FLAKY - The following jobs failed but were likely due to flakiness present on trunk:

• pull / test-binary-size-linux-gcc / linux-job (gh) (detected as infra flaky with no log or failing log classifier)
• pull / test-models-linux-basic (vit, xnnpack-quantization-delegation, buck2, linux.2xlarge, executorch-u... / linux-job (gh) (detected as infra flaky with no log or failing log classifier)

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