beam search call result in Killed about fast-ctc-decode HOT 2 OPEN

$ # beam_cut_threshold=0
/usr/bin/time -v python test.py 
        Command being timed: "python test.py"
        User time (seconds): 8.06
        System time (seconds): 19.55
        Percent of CPU this job got: 123%
        Elapsed (wall clock) time (h:mm:ss or m:ss): 0:22.43
        Average shared text size (kbytes): 0
        Average unshared data size (kbytes): 0
        Average stack size (kbytes): 0
        Average total size (kbytes): 0
        Maximum resident set size (kbytes): 42,787,016
        Average resident set size (kbytes): 0
        Major (requiring I/O) page faults: 0
        Minor (reclaiming a frame) page faults: 10706916
        Voluntary context switches: 148
        Involuntary context switches: 2336
        Swaps: 0
        File system inputs: 0
        File system outputs: 0
        Socket messages sent: 0
        Socket messages received: 0
        Signals delivered: 0
        Page size (bytes): 4096
        Exit status: 0
$
$ # beam_cut_threshold=0.000125
$ /usr/bin/time -v python test.py 
        Command being timed: "python test.py"
        User time (seconds): 3.36
        System time (seconds): 4.11
        Percent of CPU this job got: 388%
        Elapsed (wall clock) time (h:mm:ss or m:ss): 0:01.92
        Average shared text size (kbytes): 0
        Average unshared data size (kbytes): 0
        Average stack size (kbytes): 0
        Average total size (kbytes): 0
        Maximum resident set size (kbytes): 2,734,556
        Average resident set size (kbytes): 0
        Major (requiring I/O) page faults: 0
        Minor (reclaiming a frame) page faults: 693781
        Voluntary context switches: 137
        Involuntary context switches: 679
        Swaps: 0
        File system inputs: 0
        File system outputs: 0
        Socket messages sent: 0
        Socket messages received: 0
        Signals delivered: 0
        Page size (bytes): 4096
        Exit status: 0