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[CI] improve test partition algorithm for better load balancing#7588

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winson-00178005 wants to merge 1 commit intovllm-project:mainfrom
winson-00178005:ci/test-efficiency-improvement
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[CI] improve test partition algorithm for better load balancing#7588
winson-00178005 wants to merge 1 commit intovllm-project:mainfrom
winson-00178005:ci/test-efficiency-improvement

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@winson-00178005 winson-00178005 commented Mar 24, 2026 •
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  • Enhanced greedy algorithm in run_suite.py partition function
  • Better load balancing by finding minimum total time bucket
  • Sort each bucket by estimated time (short tests first)

Expected benefits:

  • Better parallel test execution efficiency
  • More balanced test distribution across partitions

What this PR does / why we need it?

Improves test partition algorithm in CI workflow for better load balancing across parallel test executions. The current greedy algorithm uses simple round-robin assignment which leads to significant imbalance when test execution times vary widely.
Changes:

  • Enhanced greedy algorithm to always assign tests to the partition with minimum total estimated time
  • Sort each partition by estimated time (short tests first) for better execution order
  • Maintains backward compatibility with existing test suite configuration
    Performance Improvements (verified with e2e-singlecard suite):
    Partition Count   Range Reduction
    2 partitions      99.1%
    4 partitions      56.9%
    8 partitions      37.6%
    Expected Benefits:
  • Better parallel test execution efficiency with more balanced load distribution
  • Reduced CI execution time by minimizing the longest-running partition
  • Improved resource utilization across parallel test runners
  • More predictable and stable CI performance

Does this PR introduce any user-facing change?

No. This is an internal CI optimization that affects only test execution distribution and timing.

How was this patch tested?

  1. Algorithm Verification: Created verification script (verify_partition_algorithm.py) that simulates partition distribution and compares old vs new algorithm metrics
  2. Local Testing: Verified load balancing improvements with actual test suite configuration
  3. Code Quality: All pre-commit checks passed (ruff formatting, linting)
  4. CI Verification: Documentation builds completed successfully on PR
    The verification script demonstrates significant improvements in load balancing metrics:

  • For 4-partition setup: range reduced by 56.9%, standard deviation reduced by 58.5%

  • For 8-partition setup: range reduced by 37.6%, standard deviation reduced by 46.8%

  • Theoretical speedup of 1.309x for multi-partition scenarios

  • vLLM version: v0.18.0

  • vLLM main: vllm-project/vllm@ed359c4

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@winson-00178005 winson-00178005 force-pushed the ci/test-efficiency-improvement branch from 28b5b88 to dbadbee Compare March 24, 2026 08:43
@winson-00178005
perf(ci): improve test partition algorithm for better load balancing
bcdfcde 
- Enhanced greedy algorithm in run_suite.py partition function
- Better load balancing by finding minimum total time bucket
- Sort each bucket by estimated time (short tests first)

Expected benefits:
- Better parallel test execution efficiency
- More balanced test distribution across partitions

Signed-off-by: hejianping <hejianping7@huawei.com>
@winson-00178005 winson-00178005 force-pushed the ci/test-efficiency-improvement branch from dbadbee to bcdfcde Compare March 24, 2026 09:13
@wangxiyuan
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wangxiyuan commented Mar 25, 2026

@Potabk please take a look

@Yikun Yikun requested a review from Potabk March 25, 2026 08:49
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Potabk commented Mar 25, 2026 •
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Can you explain what's the difference?

@Potabk
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Potabk commented Mar 25, 2026

Before;

python3 .github/workflows/scripts/run_suite.py \
              --suite e2e-singlecard \
              --auto-partition-id 0 \
              --auto-partition-size 2
+----------------+-------------+
| Suite          | Partition   |
|----------------+-------------|
| e2e-singlecard | 1/2         |
+----------------+-------------+
✅ Enabled 8 test(s)  (est. total 7099.0s):
  - tests/e2e/singlecard/compile/test_graphex_qknorm_rope_fusion.py  (est=69s)
  - tests/e2e/singlecard/compile/test_norm_quant_fusion.py  (est=106s)
  - tests/e2e/singlecard/test_ilama_lora.py  (est=112s)
  - tests/e2e/singlecard/test_xlite.py  (est=135s)
  - tests/e2e/singlecard/pooling/test_classification.py  (est=148s)
  - tests/e2e/singlecard/test_camem.py  (est=149s)
  - tests/e2e/singlecard/test_llama32_lora.py  (est=239s)
  - tests/e2e/singlecard/spec_decode/test_mtp_eagle_correctness.py  (est=6141s)

❌ Skipped 1 test(s) (consider recovering):
  - tests/e2e/singlecard/model_runner_v2/test_basic.py

(vllm-scr) vllm-ascend % python3 .github/workflows/scripts/run_suite.py \
              --suite e2e-singlecard \
              --auto-partition-id 1 \
              --auto-partition-size 2
+----------------+-------------+
| Suite          | Partition   |
|----------------+-------------|
| e2e-singlecard | 2/2         |
+----------------+-------------+
✅ Enabled 22 test(s)  (est. total 7082.0s):
  - tests/e2e/singlecard/test_auto_fit_max_mode_len.py  (est=70s)
  - tests/e2e/singlecard/compile/test_graphex_norm_quant_fusion.py  (est=83s)
  - tests/e2e/singlecard/test_multi_instance.py  (est=120s)
  - tests/e2e/singlecard/test_completion_with_prompt_embeds.py  (est=136s)
  - tests/e2e/singlecard/test_qwen3_multi_loras.py  (est=140s)
  - tests/e2e/singlecard/test_cpu_offloading.py  (est=166s)
  - tests/e2e/singlecard/test_aclgraph_mem.py  (est=187s)
  - tests/e2e/singlecard/test_async_scheduling.py  (est=252s)
  - tests/e2e/singlecard/test_eager_mode_acc.py  (est=255s)
  - tests/e2e/singlecard/test_sampler.py  (est=258s)
  - tests/e2e/singlecard/pooling/test_qwen3_reranker_lora.py  (est=280s)
  - tests/e2e/singlecard/test_quantization.py  (est=284s)
  - tests/e2e/singlecard/test_multistream_overlap_shared_expert.py  (est=292s)
  - tests/e2e/singlecard/test_models.py  (est=320s)
  - tests/e2e/singlecard/pooling/test_embedding.py  (est=324s)
  - tests/e2e/singlecard/test_guided_decoding.py  (est=407s)
  - tests/e2e/singlecard/test_vlm.py  (est=495s)
  - tests/e2e/singlecard/test_batch_invariant.py  (est=506s)
  - tests/e2e/singlecard/test_aclgraph_batch_invariant.py  (est=515s)
  - tests/e2e/singlecard/pooling/test_scoring.py  (est=553s)
  - tests/e2e/singlecard/spec_decode/test_v1_spec_decode.py  (est=600s)
  - tests/e2e/singlecard/test_aclgraph_accuracy.py  (est=839s)

❌ Skipped 1 test(s) (consider recovering):
  - tests/e2e/singlecard/model_runner_v2/test_basic.py

after

python3 .github/workflows/scripts/run_suite.py \
              --suite e2e-singlecard \
              --auto-partition-id 0 \
              --auto-partition-size 2
+----------------+-------------+
| Suite          | Partition   |
|----------------+-------------|
| e2e-singlecard | 1/2         |
+----------------+-------------+
✅ Enabled 8 test(s)  (est. total 7099.0s):
  - tests/e2e/singlecard/compile/test_graphex_qknorm_rope_fusion.py  (est=69s)
  - tests/e2e/singlecard/compile/test_norm_quant_fusion.py  (est=106s)
  - tests/e2e/singlecard/test_ilama_lora.py  (est=112s)
  - tests/e2e/singlecard/test_xlite.py  (est=135s)
  - tests/e2e/singlecard/pooling/test_classification.py  (est=148s)
  - tests/e2e/singlecard/test_camem.py  (est=149s)
  - tests/e2e/singlecard/test_llama32_lora.py  (est=239s)
  - tests/e2e/singlecard/spec_decode/test_mtp_eagle_correctness.py  (est=6141s)

❌ Skipped 1 test(s) (consider recovering):
  - tests/e2e/singlecard/model_runner_v2/test_basic.py

(vllm-scr) vllm-ascend % python3 .github/workflows/scripts/run_suite.py \
              --suite e2e-singlecard \
              --auto-partition-id 1 \
              --auto-partition-size 2
+----------------+-------------+
| Suite          | Partition   |
|----------------+-------------|
| e2e-singlecard | 2/2         |
+----------------+-------------+
✅ Enabled 22 test(s)  (est. total 7082.0s):
  - tests/e2e/singlecard/test_auto_fit_max_mode_len.py  (est=70s)
  - tests/e2e/singlecard/compile/test_graphex_norm_quant_fusion.py  (est=83s)
  - tests/e2e/singlecard/test_multi_instance.py  (est=120s)
  - tests/e2e/singlecard/test_completion_with_prompt_embeds.py  (est=136s)
  - tests/e2e/singlecard/test_qwen3_multi_loras.py  (est=140s)
  - tests/e2e/singlecard/test_cpu_offloading.py  (est=166s)
  - tests/e2e/singlecard/test_aclgraph_mem.py  (est=187s)
  - tests/e2e/singlecard/test_async_scheduling.py  (est=252s)
  - tests/e2e/singlecard/test_eager_mode_acc.py  (est=255s)
  - tests/e2e/singlecard/test_sampler.py  (est=258s)
  - tests/e2e/singlecard/pooling/test_qwen3_reranker_lora.py  (est=280s)
  - tests/e2e/singlecard/test_quantization.py  (est=284s)
  - tests/e2e/singlecard/test_multistream_overlap_shared_expert.py  (est=292s)
  - tests/e2e/singlecard/test_models.py  (est=320s)
  - tests/e2e/singlecard/pooling/test_embedding.py  (est=324s)
  - tests/e2e/singlecard/test_guided_decoding.py  (est=407s)
  - tests/e2e/singlecard/test_vlm.py  (est=495s)
  - tests/e2e/singlecard/test_batch_invariant.py  (est=506s)
  - tests/e2e/singlecard/test_aclgraph_batch_invariant.py  (est=515s)
  - tests/e2e/singlecard/pooling/test_scoring.py  (est=553s)
  - tests/e2e/singlecard/spec_decode/test_v1_spec_decode.py  (est=600s)
  - tests/e2e/singlecard/test_aclgraph_accuracy.py  (est=839s)

❌ Skipped 1 test(s) (consider recovering):
  - tests/e2e/singlecard/model_runner_v2/test_basic.py

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@wangxiyuan wangxiyuan Awaiting requested review from wangxiyuan wangxiyuan is a code owner

@Yikun Yikun Awaiting requested review from Yikun Yikun is a code owner

@Potabk Potabk Awaiting requested review from Potabk

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