Not a V8 dev, but: - What's the offending code triggering the opt/deopt loop look like? That should help quite a bit in understanding what's going on.
- Opt/deopt loops are engine bugs - it should never do that. V8 should figure out at some point whether to optimize or completely bail out. Feel free to report it at https://bugs.chromium.org/p/v8/issues/list. On Tuesday, September 4, 2018 at 5:33:28 PM UTC-4, Taylor Dondich wrote: > > So I'm building a NES(Nintendo) emulator in Javascript and I'm doing > optimizations to get the emulation to run faster. Code is located at: > https://github.com/tdondich/vue-2a03-emu > > So, I have done a dump of v8 activity using --trace-opt and --trace-deopt > > I'm seeing a lot of deopt over and over for certain critical functions. > V8 will mark to opt, optimize, then do a soft deopt, over and over on the > same functions. > > So, my question is, what are good strategies to defend against this? I'd > rather it optimizes once and is good to go on these functions. > > For example, I see: > [deoptimizing (DEOPT soft): begin 0x4356287660f9 <JSFunction tick (sfi = > 0000435628765439)> (opt #112) @253, FP to SP delta: 152, caller sp: > 0x00202c9fd7d8] > ;;; deoptimize at <http://localhost:3000/js/nesppu.js:336:30>, > Insufficient type feedback for generic named access > > But documentation on insufficient type feedback for generic named access > nowhere to be found. How can I restructure my code to help avoid this? Or > the same for "Insufficent type feedback for generic named access". > > So this goes on over and over, with the same depots happening on the same > functions all the time (and my emu runs loops at over 3 million iterations > a second). > > Any insight? > > Thanks! First time going this level with V8. It's fun! > > Taylor Dondich > > > > -- -- v8-users mailing list v8-users@googlegroups.com http://groups.google.com/group/v8-users --- You received this message because you are subscribed to the Google Groups "v8-users" group. To unsubscribe from this group and stop receiving emails from it, send an email to v8-users+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout.
