On 12/20/2013 06:24 AM, Julien Wajsberg wrote: > Hey ! > > I apologize for the cross post, I do this because I think this mail is > useful for both teams. > > 2013 has been a great year for the developer tools. As a regular user of > Firebug and now of the Developer tools, I can see the tremendous > improvements that happened this year. > > Now is a great time to write a wishlist for 2014. This is only a > developer's wishlist, nothing more. > > In 2013 we've mainly seen improvement in the Devtools itself. Now in > 2014 it should be the year where Devtools engineers gets to talk with > other team's engineers (that's why I CC the js engine folks as well). I > know this is already happening, but maybe not enough? > > So here is my wishlist (please cope with any inacuraccies I could make): > * have diagnostics about what happens within the JS engine: > + when and why objects are handled as Hashmap instead of Structs (why > === which JS code is producing this) > + when and why functions are deoptimized > > * have diagnostics about what happens in the memory and other GC-related > stuff > + know when a GC happens (see below for the Profiler) > + have a tool that shows the memory consumption over time (à la > jconsole, cf [1], or visualvm [2])
I'm also sad that we haven't gotten something like this hooked up yet. For now I'd recommend the excellent extension memchaser[1]. If you need more detail you can turn on javascript.options.mem.log in about:config and look at individual GC's in your browser console. 1 - https://addons.mozilla.org/en-US/firefox/addon/memchaser/ > + have a tool that shows the various memory generations in a runtime > way (à la visualGC [3]) At the moment the generation is "tenured." Once we turn on generational GC we can easily get that data though, so it should be doable. > + (you can see I did some Java in the past ;) ) > + best of the best: show the JS locations where the most object > creations and deletions happen > > * Have a web developer-friendly profiler > + show the main events happening while a webpage is rendering: css > refresh styles, reflow, repaint > + ideally we should also see _why_ these events are happening, tracing > back to a JS line > + show when a GC happens, show also why this happens if possible and > if it makes sense > > [1] > http://docs.oracle.com/javase/7/docs/technotes/guides/management/figures/memtab.gif > [2] http://www.cubrid.org/files/attach/images/220547/126/316/visual-vm.png > [3] > http://www.cubrid.org/files/attach/images/220547/126/316/visual-gc-execution.png > > I can file bugs for all this if they don't already exist, but what I'd > like is to have someone from your team that will make (part of) my > dreams happen. > > The bottom line is: we probably have smaller teams than our competitors, > and that's exactly why we can be better: we can easily talk to each > other, we can be more agile. > > Thanks for reading, have a great party for the end of year! 2014 will be > a great year. > > > > _______________________________________________ > dev-tech-js-engine-internals mailing list > [email protected] > https://lists.mozilla.org/listinfo/dev-tech-js-engine-internals > _______________________________________________ dev-tech-js-engine-internals mailing list [email protected] https://lists.mozilla.org/listinfo/dev-tech-js-engine-internals
