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<p class="MsoNormal"><span style="font-family:"Calibri",sans-serif">Simon, Ben, Omer<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-family:"Calibri",sans-serif">As you’ll see in comments 55-72 of
<a href="https://ghc.haskell.org/trac/ghc/ticket/9476">https://ghc.haskell.org/trac/ghc/ticket/9476</a>, Sebastian has been a bit flummoxed by the task of measure residency profiles; that is, how much data is truly live during execution.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-family:"Calibri",sans-serif">A major GC measures that, but we are vulnerable to exactly when it happens (even with -G1) and that can lead to irreproducible results.
<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-family:"Calibri",sans-serif">I think what we want is a way to trigger GC at very regular intervals, after (say) each 10kbytes or 100kbytes or 1Mbyte of allocation. That might be expensive, but we’d get reproducible results.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-family:"Calibri",sans-serif">I don’t think that is possible right now – see the ticket – but it would be easy enough to do wouldn’t it? Just give only 10k or 100k or 1M to the allocator when setting it running again.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-family:"Calibri",sans-serif">Would you consider this? Or are we just missing something obvious?<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-family:"Calibri",sans-serif">Needless to say, we want to do all this with full optimisation on, no cost-centre profiling.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-family:"Calibri",sans-serif">Thanks<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-family:"Calibri",sans-serif">Simon<o:p></o:p></span></p>
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