CPU only sample will hang

[LukeLIN-web]

When I use this setting,

    exp_id = 'fixed_depatch'
    request_mode = 'Fixed'
    sample_mode = 'CPU' # 'CPU', 'GPU', 'Auto'
    uva_gpu = 'GPU' # 'GPU', 'UVA'

I run python reddit_serving.py

output

LOG>>> P2P Access Initilization
LOG>>> 100% data cached
LOG>>> feature order is loaded
LOG >>> Memory Budge On 0 is 534 MB
LOG >>> Memory Budge On 1 is 534 MB
Data load finished
Enable P2P Access Between 0 <---> 1 
Elapsed time: 0.000009seconds
Elapsed time: 0.000008seconds
CPU Sampler 1 Start
CPU Sampler 0 Start

It cannot have any result_queue.get()

[LukeLIN-web]

I find in serving.py line 129
result_queue.put((res, time.perf_counter()-start)) will stuck.