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sglang/test/registered/unit/mem_cache/test_quantized_kv_pool.py
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# Copyright 2026 SGLang Team
# Licensed under the Apache License, Version 2.0
import types
import unittest
import torch
from sglang.test.ci.ci_register import register_cpu_ci
register_cpu_ci(est_time=5, suite="base-a-test-cpu")
class _FakeQuantMethod:
name = "fake_quant"
def __init__(self):
self.k_scales_gpu = torch.tensor([2.0], dtype=torch.float32)
self.v_scales_gpu = torch.tensor([3.0], dtype=torch.float32)
self.store_calls = []
def dequant_workspace_dtype(self):
return torch.float32
def create_buffers(self, size, head_num, head_dim, layer_num, device):
return {
"k_buffer": [
torch.zeros(
(size, head_num, head_dim), dtype=torch.uint8, device=device
)
for _ in range(layer_num)
],
"v_buffer": [
torch.zeros(
(size, head_num, head_dim), dtype=torch.uint8, device=device
)
for _ in range(layer_num)
],
"k_scale_buffer": [
torch.zeros((size, head_num, 1), dtype=torch.uint8, device=device)
for _ in range(layer_num)
],
"v_scale_buffer": [
torch.zeros((size, head_num, 1), dtype=torch.uint8, device=device)
for _ in range(layer_num)
],
"dq_k_buffer": torch.zeros(
(size, head_num, head_dim), dtype=torch.float32, device=device
),
"dq_v_buffer": torch.zeros(
(size, head_num, head_dim), dtype=torch.float32, device=device
),
"store_dtype": torch.uint8,
}
def quantize_and_store(
self,
k_buffer,
v_buffer,
k_scale_buffer,
v_scale_buffer,
loc,
cache_k,
cache_v,
k_scale=None,
v_scale=None,
):
self.store_calls.append(
{
"loc": loc,
"k_scale": k_scale,
"v_scale": v_scale,
"k_scale_buffer": k_scale_buffer,
"v_scale_buffer": v_scale_buffer,
}
)
k_buffer[loc] = 1
v_buffer[loc] = 2
k_scale_buffer[loc] = 3
v_scale_buffer[loc] = 4
class TestQuantizedKVPool(unittest.TestCase):
def test_quant_method_owns_buffers_and_store_path(self):
from sglang.srt.mem_cache.memory_pool import MHATokenToKVPool
quant_method = _FakeQuantMethod()
pool = MHATokenToKVPool(
size=4,
page_size=1,
dtype=torch.bfloat16,
head_num=1,
head_dim=8,
layer_num=1,
device="cpu",
enable_memory_saver=False,
quant_method=quant_method,
)
self.assertTrue(pool.is_quantized_kv_cache)
self.assertIs(pool.quant_method, quant_method)
self.assertIsNotNone(pool.k_scale_buffer)
self.assertIs(pool.get_dequant_workspace()[0], pool.dq_k_buffer)
loc = torch.tensor([0, 1], dtype=torch.int64)
layer = types.SimpleNamespace(layer_id=0)
pool.set_kv_buffer(
layer,
loc,
torch.zeros((2, 1, 8), dtype=torch.bfloat16),
torch.zeros((2, 1, 8), dtype=torch.bfloat16),
)
self.assertEqual(len(quant_method.store_calls), 1)
call = quant_method.store_calls[0]
self.assertIs(call["loc"], loc)
self.assertTrue(torch.equal(call["k_scale"], quant_method.k_scales_gpu[0:1]))
self.assertTrue(torch.equal(call["v_scale"], quant_method.v_scales_gpu[0:1]))
self.assertEqual(pool.k_buffer[0][loc].unique().tolist(), [1])
self.assertEqual(pool.v_buffer[0][loc].unique().tolist(), [2])
if __name__ == "__main__":
unittest.main()