aph at redhat.com
Tue Dec 4 10:39:28 UTC 2018
On 12/3/18 6:24 PM, Ron Pressler wrote:
> Yes, scope variables are indeed orthogonal to fibers (although we would like to
> combine them with structured concurrency).
> Dean Long has started working on an early prototype, which he’ll
> present hopef ully soon.
Aw, I was too late. Never mind :-)
I was looking for something interesting and reasonably self-contained
> While scope locals are certainly superior to TLs from a programming
> perspective, I’m not sure beating them on sheer performance would be
> so easy. But If you have some ideas on how to do that, they would be
> most welcome.
I'm really shocked by that. ThreadLocals are *horrible*: twelve memory
loads and two conditional branches in the best case. I see John Rose's
comments about the cost of maintaining the footprint cost of today's
ThreadLocals, but the idea of searching down the stack for a binding
isn't going to delight anyone.
I don't want to poison the well before we've seen Dean Long's
prototype, though. That would be unfair, so I'll wait.
Java Platform Lead Engineer
Red Hat UK Ltd. <https://www.redhat.com>
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