<div dir="ltr">Hey Everyone,<div><br></div><div>I understood this a little differently (well, I do have direct contact with Sumeeth given that we both work in the same lab). Allow me to try and explain his proposal.</div><div>
<br>We are trying to optimise out instructions from a program (JIT-compiled OS Kernels or JIT-compiled Web Server code) during run time and we have this hypothesis that some of the decisions are best taken by the programmer himself, e.g. if statistics shows that a particular subsystem of the program being run hasn't seen any action in quite a while, the programmer is in a position to decide whether that part of the code can be optimised out of the binary or not (if the code is some highly sensitive failure detection code then I guess he wouldn't want it removed no matter what).<br>
<br>For this, we wanted to some mechanism to call back into the execution engine to get stuff like stats or to tell the execution engine to recompile a particular module or function etc.<br><br>His proposal is to introduce a callback mechanism in the execution engine that allows the internal tools to expose functions like offering stats or the ability to toggle a recompile etc. to the user program.<br>
<br>Hope that clears some things up.<br><br>Cheers,</div><div>Amogh</div></div><div class="gmail_extra"><br><br><div class="gmail_quote">On Fri, Nov 1, 2013 at 1:53 PM, Caldarale, Charles R <span dir="ltr"><<a href="mailto:Chuck.Caldarale@unisys.com" target="_blank">Chuck.Caldarale@unisys.com</a>></span> wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div lang="EN-US" link="blue" vlink="purple"><div><p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Comic Sans MS";color:blue">> </span><b><span style="font-size:10.0pt;font-family:"Tahoma","sans-serif"">From:</span></b><span style="font-size:10.0pt;font-family:"Tahoma","sans-serif""> <a href="mailto:llvmdev-bounces@cs.uiuc.edu" target="_blank">llvmdev-bounces@cs.uiuc.edu</a> [mailto:<a href="mailto:llvmdev-bounces@cs.uiuc.edu" target="_blank">llvmdev-bounces@cs.uiuc.edu</a>] <u></u><u></u></span></p>
<p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Comic Sans MS";color:blue">> </span><b><span style="font-size:10.0pt;font-family:"Tahoma","sans-serif"">On Behalf Of </span></b><span style="font-size:10.0pt;font-family:"Tahoma","sans-serif"">Kaylor, Andrew<br>
</span><span style="font-size:10.0pt;font-family:"Comic Sans MS";color:blue">> </span><b><span style="font-size:10.0pt;font-family:"Tahoma","sans-serif"">Subject:</span></b><span style="font-size:10.0pt;font-family:"Tahoma","sans-serif""> Re: [LLVMdev] [Proposal] Adding callback mechanism to Execution Engines<u></u><u></u></span></p>
<div class="im"><p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Comic Sans MS";color:blue"><u></u> <u></u></span></p><p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Comic Sans MS";color:blue">> </span><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d">If the function is in a statically linked module, you need to do something to explicitly expose it. With <u></u><u></u></span></p>
<p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Comic Sans MS";color:blue">> </span><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d">the older JIT engine you can use addGlobalMapping as Yaron suggests, but I don’t think that will work<u></u><u></u></span></p>
<p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Comic Sans MS";color:blue">> </span><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d">with MCJIT.</span><span style="font-size:10.0pt;font-family:"Comic Sans MS";color:blue"><u></u><u></u></span></p>
<p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Comic Sans MS";color:blue"><u></u> <u></u></span></p></div><p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Comic Sans MS";color:blue">Seems to work fine for us with MCJIT.<u></u><u></u></span></p>
<p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Comic Sans MS";color:blue"><u></u> <u></u></span></p><p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Comic Sans MS";color:blue"> - Chuck<u></u><u></u></span></p>
<p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Comic Sans MS";color:blue"><u></u> <u></u></span></p></div></div><br>_______________________________________________<br>
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