On Mar 20, 2014, at 12:49 AM, Aleksey Shipilev <aleksey.shipi...@oracle.com> wrote:
> On 03/20/2014 11:06 AM, Peter Levart wrote: >> I was thinking about last night, for question: "Why is this >> double-checked non-volatile-then-volatile trick not any faster than pure >> volatile variant even on ARM platform where volatile read should have >> some penalty compared to normal read?", might be in the fact that >> Raspberry Pi is a single-core/single-thread "machine". Would anyone with >> JVM JIT compiler expertise care to share some insight? I suspect that on >> such platform, the compiler optimizes volatile accesses so that they are >> performed without otherwise necessary memory fences... > > Yes, at least C2 is known to not emit memory fences on uniprocessor > machines. You need to have a multicore ARM. If you are still interested, > contact me privately and I can arrange the access to my personal > quad-core Cortex-A9. This is all very interesting but I would like to have closure so to speak on the patches that I posted. I think the questions still unresolved are: 1) Is a change of toString() necessary? 2) If #1 is “yes” then which version of the patch? (I think the most recent) 3) Are the other changes OK which are unrelated to toString()? Thanks, Brian
