On Tue, Nov 24, 2015 at 8:42 PM, Jane Chen <jxche...@gmail.com> wrote: > Is my understanding correct that turning on v8 debugging is global for all > isolates? Is there a way to turn on v8 debug for just one isolate? What is > the performance implication to turn on v8 debug?
It's per isolate, actually. Although the v8::Debug static methods could lead you to believe otherwise, they actually configure the currently active isolate. Debugged and LiveEdit'ed methods are deoptimized to baseline (full-codegen) code so they'll run slower, sometimes a lot slower. That won't really matter for an interactive debugger but if you're using it for instrumentation, it can make a significant difference. One of StrongLoop's products uses the debugger for on-the-fly function call tracing and even after optimizing everything to death, we still couldn't get closer than 50% of the original execution speed. One thing to keep in mind is that your debug message listener gets called a lot so it should be fast and refrain from doing unnecessary work. We've had issues reported against node.js where third-party debuggers would get bogged down by the number of debug events. Rule of thumb: if you're not interested in a particular event, discard it and return immediately. -- -- 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.
