subprocess.Popen strange bhaviour

[Mac Smith]

Hi,

I am using subprocess.Popen to start a movie ripping command HandBrakeCLI. My server is 64bit ubuntu server and has 8 cores. When the command starts it uses all 8 cores upto 80%-100% and works fine, but after 270 seconds the cpu usage of all the cores drops to 0% - 1%. I tried this many time this happens exactly after 270 seconds. Is there some predefined timeout??

 

[Steven D'Aprano]

Hi,

I am using subprocess.Popen to start a movie ripping command
HandBrakeCLI. My server is 64bit ubuntu server and has 8 cores. When the
command starts it uses all 8 cores upto 80%-100% and works fine, but
after 270 seconds the cpu usage of all the cores drops to 0% - 1%. I
tried this many time this happens exactly after 270 seconds. Is there
some predefined timeout??

I think you have misunderstood subprocess.Popen. It launches the new
process (HandBrakeCLI) then what happens in that new process is
independent of Python and Popen.

How are you calling HandBrakeCLI? Is it ripping directly from a device or
file, or is it reading from stdin? If reading from stdin, possibly it is
waiting for more data from you. Or perhaps it has simply finished ripping
and there's nothing else for it to do and the process ends.