100218: BigInteger staticRandom field (original) (raw)

David Holmes david.holmes at oracle.com
Wed Jan 4 00:08:57 UTC 2012

Hi Paul,

For some reason this email, despite being dated Dec 14, only just appeared in my inbox on Jan 3!

On 14/12/2011 12:44 AM, Paul Ciprich wrote:

All,

I've created a bug report to address a scalability problem with BigInteger's staticRandom field. The problem is that the shared staticRandom field causes bottlenecks with parallel code. The proposed solution is to change the staticRandom field to a ThreadLocal and eliminate the bottleneck by giving each thread its own copy of the SecureRandom object. Bug 100218 contains a patch with the proposed change if it is deemed acceptable.

As I mention in the bug report we have to ensure that we don't add unacceptable overhead to the non-concurrent case. Also I'm wondering if anyone might be relying on the existing SecureRandom instance being shared?

Can you clarify the context for the proposed fix: what code is the bottleneck (isProbablePrime?), under what conditions - is it a microbenchmark or real code?

Thanks, David Holmes

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