RFR(XL): 8185640: Thread-local handshakes

Andrew Haley aph at redhat.com
Wed Oct 25 15:16:40 UTC 2017

On 24/10/17 15:54, Robbin Ehn wrote:

> I did a fix for the interpreter performance regression, it's plain and simple, I 
> kept the polling code inside dispatch_base but made it optional as the verify oop.
> Incremental:
> http://cr.openjdk.java.net/~rehn/8185640/v5/Interpreter-Poll-7/webrev/index.html
> Manual tested with jstack and it passes: hotspot_tier1, hotspot_handshake
> It reduces the polling cost of 80%, sensitive benchmarks shows -0.44% regression 
> vs TLH off. More insensitive benchmark show no regression.

I think it's not quite right: you're missing a check in tableswitch
and fast_linearswitch.  These can be used to construct loops.

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