I could not find a flags for turbo fan, but only for "Experimental Javascript". Not sure about what this is.
I filed a bug. I don't think it is very clear but it can be a starting point. https://code.google.com/p/chromium/issues/detail?id=520045 On Wednesday, 12 August 2015 22:51:44 UTC+2, Alon Zakai wrote: > > Chrome enables its TurboFan compiler when it seems asm.js content. There > might be a chrome flags:// option to disable TurboFan, so you can try to > see if flipping that matters (or maybe a commandline flag). I don't think > there is any logging in the console for when TurboFan is used, unlike in > Firefox and Edge. > > I would file a bug on Chrome even without a very specific testcase. It's > enough to provide a link and say "this site runs 3x slower in Chrome" (with > a way to measure speed, like an fps counter). If they need further info > they can ask for it, but often they can quickly triage such things > themselves. > > On Tue, Aug 11, 2015 at 11:54 PM, Laurent Pugin <[email protected] > <javascript:>> wrote: > >> Thanks for your answers. Firefox running time is indeed roughly the same >> as native. The reason why I thought in the first place asm was not taken >> into account at all in Chrome is because the execution time is three to >> four times slower than in Firefox but also pretty much the same as with a >> browser with no asm support (e.g., Safari). See it here (loading time in >> the console) >> >> http://www.verovio.org/mei-viewer-debug.xhtml?examples/downloads/Hummel_Concerto_for_trumpet.mei >> >> Is there a way to see in Chrome if it is actually compiling to asm? >> >> Otherwise I will try to isolate a test case and file a bug to Chrome if I >> can reproduce it. >> >> On Tuesday, 11 August 2015 18:46:47 UTC+2, Alon Zakai wrote: >>> >>> > it might be useful to file a ticket in the Chromium issue tracker >>> >>> I agree, it sounds like a perf bug in Chrome. Best thing is to file an >>> issue for them to take a look at. >>> >>> On Tue, Aug 11, 2015 at 8:19 AM, Floh <[email protected]> wrote: >>> >>>> No, sorry, no idea. I try to avoid the C++ RTTI system ;) >>>> >>>> I was thinking about tweaking the outlining-limit (see: >>>> http://mozakai.blogspot.de/2013/08/outlining-workaround-for-jits-and-big.html), >>>> >>>> if the generated code contains very large functions, JS engines may not >>>> optimize them. I was bitten by this problem a long time ago with sqlite. >>>> If >>>> this would be a problem you would get warnings about large functions in >>>> the >>>> linker step. >>>> >>>> But dynamic_cast, I have no idea what the problem could be... even if >>>> it is used heavily I couldn't imagine what would be so expensive about it. >>>> >>>> Is the performance in Firefox roughly the same as a native optimized >>>> executable, or is this also a lot slower? >>>> >>>> An isolated test case might be helpful, it could actually be a more >>>> serious code generation issue and/or a pathological case for Google's JS >>>> engine (in this case it might be useful to file a ticket in the Chromium >>>> issue tracker). >>>> >>>> Cheers, >>>> -Floh. >>>> >>>> >>>> Am Dienstag, 11. August 2015 16:05:39 UTC+2 schrieb Laurent Pugin: >>>>> >>>>> >>>>>> I would advice to compile your code with optimization on and -g2 >>>>>> (preserves function names), and then use Chrome's JS profiler (part of >>>>>> Chrome Developer Tools panel). This should give you an idea what >>>>>> functions >>>>>> are especially slow and perhaps provide a hint which C/C++ code is the >>>>>> problem. >>>>>> >>>>> >>>>> It seems that dynamic_cast takes quite some of the time (nearly 50%?). >>>>> Any thoughts? >>>>> >>>>> -- >>>> You received this message because you are subscribed to the Google >>>> Groups "emscripten-discuss" group. >>>> To unsubscribe from this group and stop receiving emails from it, send >>>> an email to [email protected]. >>>> For more options, visit https://groups.google.com/d/optout. >>>> >>> >>> -- >> You received this message because you are subscribed to the Google Groups >> "emscripten-discuss" group. >> To unsubscribe from this group and stop receiving emails from it, send an >> email to [email protected] <javascript:>. >> For more options, visit https://groups.google.com/d/optout. >> > > -- You received this message because you are subscribed to the Google Groups "emscripten-discuss" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. For more options, visit https://groups.google.com/d/optout.
