in reply to Re^2: Do I need to use Coro instead of threads/forks
in thread Do I need to use Coro instead of threads/forks

Biggest problem is main threads must wait till all threads return data,

Why is that a problem?

As I understand it, you have a cgi that accepts some user search terms. Once those search terms are returned to you, you then want to forward those terms to several vendor sites, aggregate the information they return to you, and then present the aggregation back to the user. (Is that correct? )

You cannot present the aggregation until you have all the data; so why is it a problem to wait for the threads to complete?

Unless you are hoping to present the data back to the user piecemeal, as you receive it?

In which case: set up a queue; detach the threads and have them post the data they receive to that queue. Then you main thread does not have to wait for all the threads to complete; it simply monitors the queue and deals with the data as it arrives.

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.
  • Comment on Re^3: Do I need to use Coro instead of threads/forks

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Re^4: Do I need to use Coro instead of threads/forks
by mohan2monks (Beadle) on Sep 29, 2014 at 13:27 UTC

    Yes BrowserUK your understanding is correct.
    What i meant with main program must wait was exactly in the sense that i must aggregate content and hence cannot detach threads. (i never thought of queuing thinking it will be hard to manage)
    Or can i try one of your excellent suggestion here Re: Why Coro?. using OS threads for each vendor and then use coros inside them to fulfill new requirement.
    May be that should give me best of both.
    Please correct me if i am wrong.

[reply]
      Or can i try one of your excellent suggestion here Re: Why Coro?. using OS threads for each vendor and then use coros inside them to fulfill new requirement.

      For just 10 threads, mixing Coro/threads would be overkill. (It has also never been confirmed to me that Coro is thread safe.) Personally, I'd stick to the known simplicity of threads. Also, if you go the mixed architecture route, you may find yourself out in the cold as far as support is concerned. I'm pretty sure that the Coro author doesn't do threads; and I don't do Coro; so you'd be on your own if things go tits-up.

      Also, unless your vendors are unusually tolerant; if you going hitting their websites with multiple concurrent requests, you are likely to get your accounts suspended. You may even find that hitting them with large numbers of requests serially with be frowned upon unless you put some delays between each request.

      My advice is: stick to one thread per vendor and a simple serial loop over the request to each vendor. Once you have that working, you can benchmark and look for opportunities to improve performance if it proves necessary.

      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.
[reply]

        Thanks for your support.
        I have tried both approaches with OS threads and Coro.
        As above started one OS thread per vendor (used limited functionality for 3 vendors) and serial loop for inside calls per thread.
        With Coro started 3 threads and each doing inside calls asynchronously.
        Even though Coro seems to fetch all results in parallel overall response time for Coro is much higher.
        Is this because Coro is running in a single process while OS threads has 4.
        I thought as my scripts waits for IO for larger amount of time compared to actually process the received data Coro should win.

        I have logged request and response times for SOAP calls for both as below. 

        Using OS threads total time 13 seconds

Start time Tue Sep 30 15:29:00 2014
Request 859 sent time Tue Sep 30 15:29:01 2014        #thread 1
Request 532 sent time Tue Sep 30 15:29:01 2014        #thread2    
Request 906 sent time Tue Sep 30 15:29:02 2014        #thread3
Response 859 receive time Tue Sep 30 15:29:03 2014    #thread 1 respon
+se
Request 155 sent time Tue Sep 30 15:29:03 2014
Response 532 receive time Tue Sep 30 15:29:03 2014    #thread 2 respon
+se
Request 232 sent time Tue Sep 30 15:29:04 2014
Response 906 receive time Tue Sep 30 15:29:04 2014    #thread 3 respon
+se
Request 870 sent time Tue Sep 30 15:29:04 2014
Response 870 receive time Tue Sep 30 15:29:06 2014
Request 570 sent time Tue Sep 30 15:29:06 2014
Response 232 receive time Tue Sep 30 15:29:07 2014
Response 155 receive time Tue Sep 30 15:29:07 2014
Request 461 sent time Tue Sep 30 15:29:07 2014
Response 570 receive time Tue Sep 30 15:29:09 2014
Request 585 sent time Tue Sep 30 15:29:09 2014
Response 585 receive time Tue Sep 30 15:29:10 2014
Response 461 receive time Tue Sep 30 15:29:10 2014
Request 479 sent time Tue Sep 30 15:29:10 2014
Response 479 receive time Tue Sep 30 15:29:13 2014

Using Coro's total time 31 sec
Coros 
Start time Tue Sep 30 16:03:53 2014
Request 812 sent time Tue Sep 30 16:03:53 2014        #thread1
Request 923 sent time Tue Sep 30 16:03:54 2014        #thread2
Request 942 sent time Tue Sep 30 16:03:57 2014        #thread3
Response 812 receive time Tue Sep 30 16:03:59 2014    #thread1 respons
+e
Response 923 receive time Tue Sep 30 16:04:00 2014    #thread2 respons
+e
Response 942 receive time Tue Sep 30 16:04:01 2014    #thread3 respons
+e
# individual threads starting sub threads async 
Request 312 sent time Tue Sep 30 16:04:01 2014
Request 607 sent time Tue Sep 30 16:04:02 2014
Request 578 sent time Tue Sep 30 16:04:03 2014
Request 675 sent time Tue Sep 30 16:04:04 2014
Request 310 sent time Tue Sep 30 16:04:05 2014
Request 720 sent time Tue Sep 30 16:04:06 2014
Request 502 sent time Tue Sep 30 16:04:07 2014
Request 867 sent time Tue Sep 30 16:04:08 2014
Response 312 receive time Tue Sep 30 16:04:11 2014
Response 607 receive time Tue Sep 30 16:04:13 2014
Response 578 receive time Tue Sep 30 16:04:16 2014
Response 675 receive time Tue Sep 30 16:04:18 2014
Response 310 receive time Tue Sep 30 16:04:21 2014
Response 720 receive time Tue Sep 30 16:04:22 2014
Response 502 receive time Tue Sep 30 16:04:24 2014
Response 867 receive time Tue Sep 30 16:04:26 2014

        [download]

        May be i am better of with BrowserUK suggested approach or have not understood Coro correctly.
        please suggest.

[reply]
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