not able to run threads simultaneosly in python
Question: 
    from threading import Thread
    import time
    
    def Function1():
        print "11"
        print "12"
        time.sleep(5)
        print "13"
        print "14"
    
    def Function2():
        print "21"
        print "22"
        time.sleep(10)
        print "23"
        print "24"
    
    for i in range(3)    
        t1= Thread(target=Function1())
        t2= Thread(target=Function2())
        t1.start()
        t2.start()
    

Above program runs sequentially...

    
    
    11
    12
    13
    14
    21
    22
    23
    24
    
    11
    12
    13
    14
    21
    22
    23
    24
    
    11
    12
    13
    14
    21
    22
    23
    24
    

how to run two functions(threads) simultaneously?? I don't want to use
multiprocessing.. I need to write python script for performance testing...for
that i need threads to run simultaneously Is there any way to solve this
problem?


Answer: > how to run two functions(threads) simultaneously? I don't want to use
> multiprocessing..

Unfortunately, you can't really have these two simultaneously (or at least,
you can't run things truly concurrently using `threading`). This is an
[inherent limitation of the CPython interpreter's
GIL](http://jessenoller.com/blog/2009/02/01/python-threads-and-the-global-
interpreter-lock).

The only thing that `threading` gives is single-core context switching, where
the interpreter will run a function on a single core, then swap it out
temporarily and run a different function on single core, etc. This is possibly
useful for applications that do something while, e.g., monitoring user input,
but that's about it.

