Re^7: Allowing user to abort waitpid

you found that a problem in practice?

No. I have no direct personal experience of any of it. I was just countering the patronising tone of the post to which I replied.

I did however learn a little of the limitations of *nix event loop processing in relation to a piece of work I did almost 4 years ago. (There's even a question I asked here that came out of it.)

Essentially, that piece of work involved developing a high-performance, high-availability, low-latency distributed caching mechanism. Kind of like memcache on steroids (and actually a replacement for it for a very particular purpose).

My involvement was purely on the hashing side of the problem with other people taking care of the network stuff. But for my own development & testing purposes, I wrote a (simple; C) multi-threaded event-loop server because the real thing was being written for Linux, and I don't run Linux.

In one of my communications with the server developers, I happened to mention the kind of response rates I was getting and they basically accused me of lying. They simply didn't believe the numbers I'd mentioned; as their pselect server was achieving nothing like the same.

Some of it was down to the fact that I wasn't actually responding with a full response to the clients; just closing the connections. Some was due to the fact that the "clients" were another multi-threaded, multiplexing program pretending to be lots of clients, and running in the same box, thus excluding all network latencies and much of the stack latencies.

But the primary problem was the O(n) inefficiency of pselect. And so I got to watch (via email) as they went through the various options available and see the objections raised by various parties. What I posted was basically a summary of them; except I added the 'not available from perl' (the OP's question was a Perl application).

The initial trial was done using kqueue and processes under RedHat. For production it was replaced by multi-threaded, multiplexing server using Alertable I/O under Winserver 2008.

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". I knew I was on the right track :)

In the absence of evidence, opinion is indistinguishable from prejudice.

Comment on Re^7: Allowing user to abort waitpid

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Re^8: Allowing user to abort waitpid by Anonymous Monk on Mar 08, 2016 at 15:50 UTC
I was just countering the patronising tone of the post to which I replied. Hmm. I didn't want it to come off this way, but you made fun of funny nixers in the first place, so you probably deserved it :P But the primary problem was the O(n) inefficiency of pselect. Yes, that sounds right (unlike some of their objections to epoll).	[reply]
Re^9: Allowing user to abort waitpid by BrowserUk (Patriarch) on Mar 08, 2016 at 15:52 UTC
but you made fun of funny nixers in the first place, so you probably deserved it :P Absolutely! :) 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". I knew I was on the right track :) In the absence of evidence, opinion is indistinguishable from prejudice.	[reply]