RFR 8066397 Remove network-related seed initialization code in ThreadLocal/SplittableRandom

Paul Sandoz paul.sandoz at oracle.com
Tue Dec 2 10:21:08 UTC 2014

On Dec 2, 2014, at 11:10 AM, Alan Bateman <Alan.Bateman at oracle.com> wrote:

> On 02/12/2014 10:02, Paul Sandoz wrote:
>> Hi,
>> Please find below a patch to remove the networking code computing a seed in ThreadLocal/SplittableRandom.
>> We thought it a good idea at the time :-) but subsequently on certain platforms this results in very high initalization costs that can propagate to other classes such as ConcurrentSkipList*.
>> The short-term solution is to remove this code and fallback just using current system time. This needs to be back-ported to 8u40.
>> A longer term solution is to provide a simple public API to get access to some seed bytes that is optimal for the underlying platform, for example, based on Peter's investigations. For linux /dev/urandom is sufficient as a source of bytes. The main problem seems to be Windows. It would also be nice to back-port to say 8u60 using a private API and update TLR/SR.
>> Paul.
> The approach seems pragmatic and the change looks okay to me


> (you might have some unused imports to removed too).

Doh! yes, removed.


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