Guys, This piqued my interest. Where can I find the draft JEP and the sources for this, please?
Kees Jan > On 4 Aug 2015, at 23:22, Jeremy Manson <jeremyman...@google.com> wrote: > > Thanks, Staffan. I've been tinkering with a draft JEP, but it has been going > slowly because of other craziness in my life. Some responses: > > 1) It was a fair bit of work to do it, mostly because it was the first time I > had tinkered with c2. This was 5 years ago. Most of the work since then has > been dealing with merge conflicts. > > 2) I did envision a JVMTI interface. More in the JEP. > > 3) We have some internal tests, but obviously, we'd have to figure out how to > externalize them. For native code, it's much easier only to have to worry > about building and running on Linux. Presumably, there's already code in > there for JVMTI. > > I'll try to get a JEP going for real, although it might not happen in the > next week or so, because I'm moving next week (+the JVMLS). > > Jeremy > > On Tue, Aug 4, 2015 at 4:04 AM, Staffan Larsen <staffan.lar...@oracle.com> > wrote: > Hi, > > Sorry for being away for so long. > > If memory serves me right then the current AllocObjectInNewTLAB JFR event was > written as a way to quickly get some allocation profiling information with a > minimum of VM changes. It probably also carried over to Hotspot from JRockit. > I agree that we can and should collect better information than what that > event does. > > I like the approach of instrumenting the interpreter and compiler to do the > sampling. I had thought it would be a lot of work to do it and was reluctant > to go down that path. If the work is already done and Jeremy has maintained > it for a few years without great problems, I think we should look at bringing > it in. I am not worried about the overhead of a decrement and a compare in > the allocation path, but of course we should benchmark that. > > It wasn’t clear to me from the discussion how (or if) this was being exposed > to end users. Was the proposal to just have the native entry points in the VM > and have these be used by various agents? Would this be part of JVMTI? > > I think a draft JEP would be the logical next step and make it easier for us > all to discuss what exactly the proposal should contain. Also, let’s not > forget the need for tests for the feature. > > Thanks, > /Staffan > > > -- Kees Jan http://java-monitor.com/ kjkos...@kjkoster.org +31651838192 The secret of success lies in the stability of the goal. -- Benjamin Disraeli
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