Thanks, I see now that the new stats would also be useful for Chrome because they are emitted after each GC whereas memory-infra gives heap stats independent from GC.
Adding "V8.GC_Heap_Stats" event to "v8.gc_stats" category and improving 'tools/heap-stats' sounds good to me. On Tue, Apr 23, 2019 at 9:02 PM Pierre Langlois <pierre.langl...@arm.com> wrote: > Thanks for the replies! > > Ah it's a shame we don't have a solution for d8. I've been toying with > memory-infra and it seems very useful, however, I was hoping for > something that would work regardless of the embedder, and that would be > friendly to building tools around it. > > At the moment for example, it's easy to write scripts that parse the > trace output from "v8.gc_stats". And for example, then we can use it to > track OPTMIZED_FUNCTION objects on the heap to see if a patch has > potentially improved code size. > > So I'm hoping to get heap statistics the same way, but I want to make > sure it's actually useful before sending out a patch :-). Already, if we > add an event for every GC it would show up in the chrome://tracing view > with heap details, so you could get a little more information in between > memory-infra dumps. Although a timeline with the heap going up and down > would be much better. > > On the V8 side of things, we could improve 'tools/heap-stats' to also > include heap statistics into the timeline, on top of object statistics. > > What do you think? > > Ulan Degenbaev writes: > > > I would also suggest to try memory-infra if you use Chrome. It can > sample V8 heap stats periodically or on demand via the inspector protocol. > It uses GetHeapStatistics() and GetHeapSpaceStatistics() API [1] > > > > I don't think we have a solution for d8. > > > > [1]: > https://cs.chromium.org/chromium/src/gin/v8_isolate_memory_dump_provider.cc?rcl=c16fb58b2bca1bba7248ac509dde60ececf94d63&l=156 > > > > On Tue, Apr 23, 2019 at 12:46 PM Ross McIlroy <rmcil...@google.com > <mailto:rmcil...@google.com>> wrote: > > +Ulan Degenbaev<mailto:u...@google.com> > > > > Hi Pierre, > > > > Have you tried the mem-infra category< > https://chromium.googlesource.com/chromium/src.git/+/master/docs/memory-infra/> > in chrome tracing? That should give you at least some of the items you are > looking for if you select the "v8" item in a mem-infra trace event. > > > > Cheers, > > Ross > > > > > > On Thu, 18 Apr 2019 at 20:46, Pierre Langlois <pierre.langl...@arm.com > <mailto:pierre.langl...@arm.com>> wrote: > > Hello! > > > > Lately I've been looking at V8's heap consumption and tooling around > > measuring and tracking it. I see we have a few different ways to do it > > and I've been thinking about adding a new one :-). So I thought I'd ask > > what you thought first. > > > > Essentially, I want to collect stats about the heap regularly, at > > every GC for instance, and then either plot this information over > > time, or do some statistics like getting the peak for each space, or > > figuring out how fragmented we are, ...etc > > > > So at the moment, to do things like that we can: > > > > * Use the V8 API or the inspector protocol. > > > > * Use --trace-gc-verbose to print statistics at every GC. > > > > * Use --trace-gc-object-stats or --enable-tracing with the > > "v8.gc_stats" category enabled to collect object statistics at every > > mark-compact GC. > > > > * ... something I missed? > > > > I started using --trace-gc-verbose and it works OK but its output is > > not very friendly for tools to consume. And on the other hand, I like > > how the TRACE macros work and are used with --trace-gc-object-stats. > > > > So I've been thinking about adding a new trace event that prints heap > > statistics, enabled with the existing `v8.gc_stats` tracing category. I > > haven't thought about all the details yet, but the current idea is the > > following: > > > > - Add a "instant" trace event for the "v8.gc_stats" category for > > every GC, both the scavenger and mark-compact, as opposed to > > --trace-gc-object-stats which triggers only using mark-compact. > > > > - The event could be called "V8.GC_Heap_Stats", to mirror > > "V8.GC_Object_Stats". > > > > - Output JSON with both global and per-space statstics, just like > > GetHeapStatistics() and GetHeapSpaceStatistics() from the V8 API do. > > > > How does this sound? Are there tools (tools/heap-stats?) that would > > benefit from this? Or do we already have ways to do this and I've missed > > it? > > > > Thanks, > > Pierre > > > > -- > > -- -- v8-dev mailing list v8-dev@googlegroups.com http://groups.google.com/group/v8-dev --- You received this message because you are subscribed to the Google Groups "v8-dev" group. To unsubscribe from this group and stop receiving emails from it, send an email to v8-dev+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout.
