Vmprof: "Undefined" in flamegraph, and "No stack trace has been recorded (profile is empty)!"

Hello all, Its seems that last changes and udpates on vmprof were in 2019, but I hope someone will help me to setup vmprof for my project. Here are the problems: I have installed vmprof client and server and when I run vmprof

by API like this:

         with open('logs/vmprof.log', 'w+b') as fd:
            vmprof.enable(fd.fileno())
            ..... some code here.....
            ..... some code here.....
            ..... some code here.....
            vmprof.disable()

it creates vmprof.log file as expected. then I upload it to my local server and as a result I see lot of "undefined" in flamegraph.

QUESTION: What to do with this undefineds. How to solve this problem?

I want to enable and disable profiling by a signal. For that I use SIGUSR signal custom handler: here is the code:
```
gevent.signal(signal.SIGUSR1, self.sigusr1_handler)
def sigusr1_handler(self):
    if not vmprof.is_enabled():
        with open('logs/vmprof.log', 'w+b') as fd:
            vmprof.enable(fd.fileno())
    else:
        vmprof.disable()
```
it creates vmprof log, but when I try to open on server there were nothing, infinite loading and preloader. I have tried to see if it works with vmprofshow but I got this message:

WARNING: The profiling completed in less than 1 seconds. Please run your programs longer! No stack trace has been recorded (profile is empty)!

QUESTION: How to solve this problem? Is it possible to enable or disable vmprof by signal?

vmprof / vmprof-python

Vmprof: "Undefined" in flamegraph, and "No stack trace has been recorded (profile is empty)!" #220