Processor support for select operations
paul.j.elschot at gmail.com
Wed Nov 12 19:09:29 UTC 2014
The difference in performance between Java and C for bit selection from
a long is already quite small, so I'll wait for the optimization on
power-of-two indexing and avoid Unsafe.
On 11-11-14 20:00, Vitaly Davidovich wrote:
> But in the meantime, just trying Unsafe to see what the perf benefit
> would be is still interesting, no?
> Sent from my phone
> On Nov 11, 2014 1:54 PM, "John Rose" <john.r.rose at oracle.com
> <mailto:john.r.rose at oracle.com>> wrote:
> On Nov 11, 2014, at 10:16 AM, Paul Elschot <paul.j.elschot at gmail.com
> <mailto:paul.j.elschot at gmail.com>> wrote:
>> A little masking might be enough to enforce the ranges, see the
>> code in
>> my other reply.
> Power-of-two array indexing is an important use case which can be
> optimized without resorting to Unsafe.
> We're working on it.
> See https://bugs.openjdk.java.net/browse/JDK-8003585
> — John
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