Time to Safepoint and HotSpot intrinsics

[Andrew Haley]

On 11/26/18 10:01 PM, Hohensee, Paul wrote:
> The compiler could estimate the cost of an iteration using some rough pessimistic heuristic and strip mine based on that.

But the compiler doesn't see the intrinsics: they are hand-coded assembly
language.

> Measuring the safepoint time directly is fragile due to inability to find all the hardware platforms that might run the JVM. A671

Sure, but all I'm suggesting is that we take an order-of-magnitude guess
and apply that to our intrinsics. It does not have to be accurate: in the
case of encryption the speed difference caused by limiting the number of
iterations is infinitesimal, but the time to safepoint difference is huge.

IMO, this is a true no brainer.

-- 
Andrew Haley
Java Platform Lead Engineer
Red Hat UK Ltd. <https://www.redhat.com>
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