I'm trying to profile the v8 execution of a web app using Chromium's content_shell with some success. But I'm also getting some odd results. I'm using a commandline like:
content_shell --no-sandbox --js-flags='--prof --noprof-lazy --log-timer-events' http://localhost:8000/mypage And then processing the v8.log with v8/tools/linux-tick-processor v8.log The resulting profile has some quirks: none of the "JavaScript" portion of the profile lists more than 0.2% of the total ticks (even though there's >500ms of JS execution time as part of the app, as shown by both plot-timer-events and the Inspector's timeline). The C++ stack, meanwhile, has several major points of interest. Most of the big ones are Blink C++ callbacks (e.g., NodeV8Internal::dispatchEventMethodCallback), and __pthread_cond_wait shows up. But the top one is "__write", usually taking >30% of the ticks. If I go down to the call stacks, I get a bunch of "LazyCompile someMethod" entries which terminate at __write, so it seems I'm still getting some idea of which JS is taking the time, but I'm rather surprised that __write is the endpoint (it's mostly DOM tree walking/manipulation). Is this expected? Also, I'm a bit surprised at the way the v8 DOM callbacks end up in the profile: those methods are usually trivial, with the real work being somewhere deep in the core of Blink. Is it expected that only the v8 entry point into Blink shows up when using the profiling tool? Any insights would be valuable. Thanks, Adam -- -- v8-users mailing list [email protected] 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 [email protected]. For more options, visit https://groups.google.com/groups/opt_out.
