RFR (XS) CR 8014233: java.lang.Thread should be @Contended

Aleksey Shipilev aleksey.shipilev at oracle.com
Fri May 10 13:27:19 UTC 2013

On 10.05.2013, at 16:17, Doug Lea <dl at cs.oswego.edu> wrote:

> On 05/09/13 10:19, Peter Levart wrote:
>> Hi Aleksey,
>> Wouldn't it be even better if just threadLocalRandom* fields were annotated with
>> @Contended("ThreadLocal") ?
>> Some fields within the Thread object are accessed from non-local threads. I
>> don't know how frequently, but isolating just threadLocalRandom* fields from all
>> possible false-sharing scenarios would seem even better, no?
> As it turns out, no. Nearly all other fields of class Thread
> are also modified mainly by or only by the current thread
> (at least after initialization). So the simplest solution
> seems to be the best one.


Although I just tried what Peter had suggested, and got even more boost on my microbenchmark. This counter-intuitive for me, since no memory layout differences could explain this in my tests. I will have to untangle this today, hold on.


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