I was wondering what similarities on-stack replacement of JITed code have with suspension with code patching.
On 9/9/05, Xiao-Feng Li <[EMAIL PROTECTED]> wrote: > Thanks, Rodrigo and Shudo. ORP had a similar approach as code patching > previously, which we called "IP hijacking". We found, as you observed, > it had some difficulties in maintenance and portability. I classified > this approach into the preemptive category. > > I suspect a given thread suspension algorithm will have different > performance characteristics depending on processor architecture, and > garbage collection algorithm as well. It deserves more study. Since > the two approaches are not much conflicting, I suggest implementing > voluntary mechanism at first for its cleanness and portability for the > first few releases of Harmony. > > Thanks, > xiaofeng > == > Intel Managed Runtime Division > > On 9/1/05, [EMAIL PROTECTED] <[EMAIL PROTECTED]> wrote: > > From: Xiao-Feng Li <[EMAIL PROTECTED]> > > > > > Thread suspension happens in many situations in JVM, such as for GC, > > > for java.lang.Thread.suspend(), etc. There are various techniques to > > > suspend a thread. Basically we can classify them into two categories: > > > preemptive and voluntary. > > > > > The preemptive approach requires the suspender, say a GC thread, > > > suspend the execution of a target thread asynchronously with IPC > > > mechanism or OS APIs. If the suspended thread happened to be in a > > > region of code (Java or native) that could be enumerated, the live > > > references were collected. This kind of region is called safe-region, > > > and the suspended point is a safe-point. If the suspended point is not > > > in safe-region, the thread would be resumed and stopped again until it > > > ended up in a safe-region randomly or on purpose. > > > > Sun's HotSpot VMs patch compiled native code to stop thread at the > > safe points, on which a stack map is provided. It's smart but prone to > > causes subtle problems, an engineer working on the VM said. > > > > Kazuyuki Shudo [EMAIL PROTECTED] http://www.shudo.net/ > > >
