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<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">Hi Jinghao,<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">The execution of callbacks is co-operative ¨C as you¡¯ve seen, they will execute when calling into the event_dispatch function. Without this guarantee it would
be very difficult to write correct programs ¨C for instance, if callbacks executed at arbitrary points, then they might see the program¡¯s data structures in an inconsistent state (or risk deadlock if synchronizing with the rest of the application).<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">You might be interested in looking at the AC programming model<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"><a href="http://research.microsoft.com/en-us/um/people/tharris/papers/2011-oopsla.pdf">http://research.microsoft.com/en-us/um/people/tharris/papers/2011-oopsla.pdf</a><o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">For historical reasons, AC is called THC in the source code. There are some examples in the test directories ¨C thctest and thcidctest. You will need to modify
your program¡¯s Hakefile to build the AC version of the stubs, in addition to the default Flounder ones. With AC, the IO operations are written in a simple synchronous style. You can then use the ¡°ASYNC¡± and ¡°DO¡FINISH¡± language features to provide additional
work that can be started while waiting for an IO operation to complete.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">--Tim<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><b><span lang="EN-US" style="font-size:10.0pt;font-family:"Tahoma","sans-serif"">From:</span></b><span lang="EN-US" style="font-size:10.0pt;font-family:"Tahoma","sans-serif""> Shi Jinghao (</span><span lang="ZH-CN" style="font-size:10.0pt">Ê·¾ºÆ£©</span><span lang="EN-US" style="font-size:10.0pt;font-family:"Tahoma","sans-serif"">
[mailto:jhshi@cs.hku.hk] <br>
<b>Sent:</b> 14 March 2012 14:14<br>
<b>To:</b> barrelfish-users@lists.inf.ethz.ch<br>
<b>Subject:</b> [Barrelfish-users] Questions about IDC: Poll or Interrupt<o:p></o:p></span></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">Hi,<o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal">I am recently working with IDC in Barrelfish, using the API generated by Flounder. I found that I need <o:p></o:p></p>
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<p class="MsoNormal">to use a separate polling thread to poll the waitset, so that my call backs can get called. <o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal">For example, when sending a message: dummy__msg_tx(binding, MKCONT(send_cb, NULL), value)<o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal">Since the send is asynchronous, I can continue to do other stuff after this call. However, I expect that<o:p></o:p></p>
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<p class="MsoNormal">my send_cb will be called (*interrupt*) once the send is success, which is not the case: I must manually poll the <o:p></o:p></p>
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<p class="MsoNormal">binding's waitset using event_dispatch to get send_cb get called.<o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal">I now use a separate polling thread to do all this stuff and it works. But I was wondering:<o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal"> - Is it designed as this way? Or I don't actually need to poll, just I don't know how...<o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal"> - If this is the way as designed, then why? This seems not that "event-driven", right?<o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal">Thanks for your reading and forgive me if I asked a stupid question.<o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal">Regards,<o:p></o:p></p>
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<p class="MsoNormal">Jinghao<o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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