On 01.03.14 21:55, Stefan Marr wrote:
Hi:
On 01 Mar 2014, at 19:44, Alexandre Bergel <alexandre.bergel@me.com> wrote:
The VM is a formidable thing in which everything happen. Exposing to the image whatâs going on in it is really pushing the innovation.
Perhaps something that could be relevant in case someone decides to implement such an interface in Cog: Just one, pretty old example: http://docs.oracle.com/javase/6/docs/platform/jvmti/jvmti.html#EventIndex
You can get access to many different information in terms of âeventsâ on the JVM. For building a profiler, more than sufficient. And, at least in my personal opinion also something that would be desirable for Cog, perhaps in a slightly more modern design, but with a similar flavor.
Oracle itself describes JVMTI as too intrusive for production use [1]. They built their own proprietary solution called Flight Recorder [2] [3] (Oracle marketing names) which AFAIK is based on JRockit technology. They are confident enough about it to explicitly recommend it for production use. They claim the overhead is about 2 to 3 %. And yes, it's a commercial feature for production and you have to unlock with: -XX:+UnlockCommercialFeatures It has a horrible UI but it's quite a nice tool. [1] http://www.oracle.com/technetwork/java/javaseproducts/mission-control/java-m... [2] http://download.oracle.com/technology/products/missioncontrol/updatesites/ba... [3] http://docs.oracle.com/javase/7/docs/technotes/guides/jfr/usingjfr.html Cheers Philippe