Files
sglang/test/srt/test_logprobs.py
Shangming Cai 70e4b21853 Fix flaky logprobs test (#10728)
Signed-off-by: Shangming Cai <csmthu@gmail.com>
2025-09-22 00:46:26 -07:00

266 lines
10 KiB
Python

import io
import os
import pickle
import random
import time
import unittest
import numpy as np
import requests
import torch
import sglang as sgl
from sglang.test.test_utils import (
DEFAULT_SMALL_MODEL_NAME_FOR_TEST,
write_github_step_summary,
)
# Dense model configuration
DENSE_MODEL_NAME = DEFAULT_SMALL_MODEL_NAME_FOR_TEST
if torch.version.hip is not None:
print("Running on AMD ROCm GPU")
DENSE_INPUT_PKL_URL = "https://huggingface.co/datasets/yushengsu/logprobs/resolve/main/sglang_baseline_2000_amd.pkl"
DENSE_TOLERANCE_MAX_DIFF = 1.4
DENSE_TOLERANCE_MEAN_DIFF = 0.1
elif torch.version.cuda is not None:
print("Running on NVIDIA CUDA GPU")
DENSE_INPUT_PKL_URL = "https://huggingface.co/datasets/font-info/logprobs/resolve/main/sglang_baseline_2000.pkl"
DENSE_TOLERANCE_MAX_DIFF = 1.5
DENSE_TOLERANCE_MEAN_DIFF = 0.1
else:
print("No GPU backend (CPU only)")
# Common configuration
TOP_K = 20
MAX_RETRIES = 3
RETRY_DELAY = 2
NUM_SAMPLES = 1000
LOGPROB_SAMPLE_RATIO = 0.5
TEMPERATURE = 1.0
class TestLogprobsDense(unittest.TestCase):
@classmethod
def setUpClass(cls):
"""Set up the test class - initialize the engine once for all tests."""
print(f"Launching SGLang Engine with {DENSE_MODEL_NAME}...")
cls.engine = sgl.Engine(
model_path=DENSE_MODEL_NAME,
random_seed=42,
skip_tokenizer_init=True,
mem_fraction_static=0.80,
)
@classmethod
def tearDownClass(cls):
"""Clean up after all tests - shutdown the engine."""
cls.engine.shutdown()
torch.cuda.empty_cache()
def load_test_data(self):
"""Load test data from Hugging Face dataset with retry mechanism."""
print(f"Loading data from {DENSE_INPUT_PKL_URL}...")
for attempt in range(MAX_RETRIES):
try:
response = requests.get(DENSE_INPUT_PKL_URL, timeout=30)
response.raise_for_status()
with io.BytesIO(response.content) as f:
records = pickle.load(f)
if not records:
raise ValueError("Empty dataset")
print(f"Successfully loaded {len(records)} records")
return records
except Exception as e:
print(f"Attempt {attempt + 1}/{MAX_RETRIES} failed: {e}")
if attempt == MAX_RETRIES - 1:
raise Exception(
f"Failed to load data after {MAX_RETRIES} attempts: {e}"
)
time.sleep(RETRY_DELAY)
def compare_meta(self, baseline_meta, sglang_meta):
"""Compare metadata between two outputs and return max and mean differences."""
diffs = []
for key in ["input_top_logprobs", "output_top_logprobs"]:
baseline_logprobs, sglang_logprobs = baseline_meta[key], sglang_meta[key]
self.assertEqual(
len(baseline_logprobs),
len(sglang_logprobs),
f"Length of {key} is not equal, sglang did not return the correct number of log probs(should be top 20)",
)
for baseline_entry, sglang_entry in zip(baseline_logprobs, sglang_logprobs):
if not baseline_entry or not sglang_entry:
continue
baseline_token_map = {tid: lp for lp, tid, _ in baseline_entry}
sglang_token_map = {tid: lp for lp, tid, _ in sglang_entry}
common_tokens = baseline_token_map.keys() & sglang_token_map.keys()
self.assertGreaterEqual(
len(common_tokens),
TOP_K / 2,
f"there are only {len(common_tokens)} common topk tokens that matches",
)
for token_id in common_tokens:
diffs.append(
abs(baseline_token_map[token_id] - sglang_token_map[token_id])
)
return max(diffs), float(np.mean(diffs))
def test_logprobs_comparison(self):
"""Test the logprobs comparison functionality with different parameter combinations."""
# Load test data with retry mechanism
records = self.load_test_data()
with self.subTest(
config={
"num_samples": NUM_SAMPLES,
"logprob_sample_ratio": LOGPROB_SAMPLE_RATIO,
"temperature": TEMPERATURE,
}
):
# Sample records for this config
test_records = random.sample(records, k=min(NUM_SAMPLES, len(records)))
random.shuffle(test_records)
# Calculate how many samples should return logprobs
logprob_count = int(len(test_records) * LOGPROB_SAMPLE_RATIO)
print(
f"Testing with {len(test_records)} samples, temperature={TEMPERATURE}"
)
print(
f"Will return logprobs for {logprob_count} samples (ratio: {LOGPROB_SAMPLE_RATIO})"
)
all_max, all_mean = [], []
logprob_returned_count = 0
# Process all records at once
input_ids = [rec["ids"] for rec in test_records]
logprob_start_lens = [rec["start_pos"] for rec in test_records]
# Determine which samples should return logprobs (randomly selected)
logprob_indices = set(
random.sample(range(len(test_records)), logprob_count)
)
return_logprob_array = [
sample_idx in logprob_indices for sample_idx in range(len(test_records))
]
# Sampling param per request
sampling_params = [
{
"temperature": TEMPERATURE,
"top_p": 1.0,
"top_k": TOP_K,
"max_new_tokens": 1,
}
for _ in test_records
]
outputs = self.engine.generate(
input_ids=input_ids,
sampling_params=sampling_params,
return_logprob=return_logprob_array,
logprob_start_len=logprob_start_lens,
top_logprobs_num=TOP_K,
)
for sample_idx, (rec, output) in enumerate(zip(test_records, outputs)):
# Only compare logprobs for samples that should have them
if sample_idx in logprob_indices:
# Safe access to meta_info and input_top_logprobs
meta_info = output.get("meta_info")
input_top_logprobs = (
meta_info.get("input_top_logprobs") if meta_info else None
)
self.assertIsNotNone(
input_top_logprobs,
f"return_logprob enabled on this sample, but input_top_logprobs is None (length: {len(input_top_logprobs) if input_top_logprobs is not None else 'N/A'})",
)
baseline_meta = rec["meta"]
sglang_meta = meta_info
max_diff, mean_diff = self.compare_meta(baseline_meta, sglang_meta)
all_max.append(max_diff)
all_mean.append(mean_diff)
logprob_returned_count += 1
else:
# Verify that logprobs were not returned for this sample
meta_info = output.get("meta_info")
input_top_logprobs = (
meta_info.get("input_top_logprobs") if meta_info else None
)
output_token_ids_logprobs = (
meta_info.get("output_token_ids_logprobs")
if meta_info
else None
)
self.assertFalse(
input_top_logprobs,
f"return_logprob is disabled on this sample, Sample {sample_idx} should not have logprobs, content: {output_token_ids_logprobs}",
)
max_of_max = max(all_max) if all_max else 0.0
mean_of_mean = np.mean(all_mean) if all_mean else 0.0
print(f"max Δ={max_of_max:.6g}")
print(f"mean Δ={mean_of_mean:.6g}")
print(
f"logprobs returned for {logprob_returned_count} samples (expected: {logprob_count})"
)
# Verify correct number of logprobs returned
self.assertEqual(
logprob_returned_count,
logprob_count,
f"Expected {logprob_count} samples with logprobs, got {logprob_returned_count}",
)
# Write results to GitHub summary
summary_content = f"""
- **Configuration**: {{"num_samples": {NUM_SAMPLES}, "logprob_sample_ratio": {LOGPROB_SAMPLE_RATIO}, "temperature": {TEMPERATURE}}}
- **Max of max Δ**: {max_of_max:.6g}
- **Mean of mean Δ**: {mean_of_mean:.6g}
- **Status**: {'✅ Passed' if max_of_max <= DENSE_TOLERANCE_MAX_DIFF and mean_of_mean <= DENSE_TOLERANCE_MEAN_DIFF else '❌ Failed'}
"""
write_github_step_summary(summary_content)
# Basic validation
self.assertIsInstance(all_max, list)
self.assertIsInstance(all_mean, list)
self.assertGreater(
len(all_max),
0,
f"No test samples processed for config {{'num_samples': {NUM_SAMPLES}, 'logprob_sample_ratio': {LOGPROB_SAMPLE_RATIO}, 'temperature': {TEMPERATURE}}}",
)
# Tolerance checks with clear error messages
failed_samples = []
for sample_idx, (max_diff, mean_diff) in enumerate(zip(all_max, all_mean)):
if max_diff > DENSE_TOLERANCE_MAX_DIFF:
failed_samples.append(
f"Sample {sample_idx}: max_diff={max_diff:.6g} > {DENSE_TOLERANCE_MAX_DIFF}"
)
if mean_diff > DENSE_TOLERANCE_MEAN_DIFF:
failed_samples.append(
f"Sample {sample_idx}: mean_diff={mean_diff:.6g} > {DENSE_TOLERANCE_MEAN_DIFF}"
)
if failed_samples:
self.fail(
f"Config {{'num_samples': {NUM_SAMPLES}, 'logprob_sample_ratio': {LOGPROB_SAMPLE_RATIO}, 'temperature': {TEMPERATURE}}} - Tolerance exceeded in {len(failed_samples)} samples:\n"
+ "\n".join(failed_samples[:5])
)
if __name__ == "__main__":
unittest.main()