Beefy Boxes and Bandwidth Generously Provided by pair Networks
good chemistry is complicated,
and a little bit messy -LW
 
PerlMonks  

comment on

( [id://3333]=superdoc: print w/replies, xml ) Need Help??
One example of stochastic behavior...

You reinvented a fork bomb. Except on windows, fork actually spawns a thread; so it might better be termed a thread-bomb in this case.

Try feeding this:  :(){ :|:& };: to bash on a *nix system and see how deterministic the DoS is.

You are also asking the child 'process' to kill its parent 'process'; but on windows they are actually just threads within the same process. Ie. You are attempting to kill your own process. In addition, you are also thread-bombing the system from within that same process. Is there any wonder that the process may not respond to the request in a predictable manner?

And you are using a random delay -- sleep 0 equates to "relinquish the rest of the current timeslice" which is an unknowable quantum of time, that could range from 0 microseconds -- if the timeslice was about to end anyway; or if there are no other processes in the system immediately eligible to run -- to N * q where N is the number of other processes and threads in the system that are eligible to run; and q is the scheduler quantum which can vary from ~5 to ~180 microseconds depending upon: a) the version of Windows; b) how that version is configured (workstation or server; foreground or background priority); c) a whole bunch of other factors.

In other words; you have programmed a random delay into your program as surely as if you had written Win32::Sleep( rand()*100 ).

Of course the behaviour is "stochastic"; That's how you programmed it to be!

Could you accept (or even recommend) the addition of something like this:

Neither!

I use kill (on windows) to good effect all the time. The difference is that I have spent enough time to understand the limitations of the emulation on my platform. I understand that they give me a fairly crude interface to the native Console control handler functionality from Perl; and that -- used carefully -- can provide functionality that I might otherwise have to dip into Inline::C or XS to gain access to.

What I would say; and have said many times; is do not attempt to use fork & the windows signals emulation to try to port *nix idioms to windows; because you will be sadly let down.

The basic problem here is the entire attempt to make Windows look like or work like some variant of *nix. It is simply far easier to write two scripts -- one for each platform -- than to try and construct and maintain one that will operate correctly on both platforms.


With the rise and rise of 'Social' network sites: 'Computers are making people easier to use everyday'
Examine what is said, not who speaks -- Silence betokens consent -- Love the truth but pardon error.
"Science is about questioning the status quo. Questioning authority".
In the absence of evidence, opinion is indistinguishable from prejudice.

In reply to Re^3: Threads and signals in Windows by BrowserUk
in thread Threads and signals in Windows by bojinlund

Title:
Use:  <p> text here (a paragraph) </p>
and:  <code> code here </code>
to format your post; it's "PerlMonks-approved HTML":



  • Are you posting in the right place? Check out Where do I post X? to know for sure.
  • Posts may use any of the Perl Monks Approved HTML tags. Currently these include the following:
    <code> <a> <b> <big> <blockquote> <br /> <dd> <dl> <dt> <em> <font> <h1> <h2> <h3> <h4> <h5> <h6> <hr /> <i> <li> <nbsp> <ol> <p> <small> <strike> <strong> <sub> <sup> <table> <td> <th> <tr> <tt> <u> <ul>
  • Snippets of code should be wrapped in <code> tags not <pre> tags. In fact, <pre> tags should generally be avoided. If they must be used, extreme care should be taken to ensure that their contents do not have long lines (<70 chars), in order to prevent horizontal scrolling (and possible janitor intervention).
  • Want more info? How to link or How to display code and escape characters are good places to start.
Log In?
Username:
Password:

What's my password?
Create A New User
Domain Nodelet?
Chatterbox?
and the web crawler heard nothing...

How do I use this?Last hourOther CB clients
Other Users?
Others surveying the Monastery: (4)
As of 2024-04-18 00:08 GMT
Sections?
Information?
Find Nodes?
Leftovers?
    Voting Booth?

    No recent polls found