RFR(M): 8195112: x86 (32 bit): implementation for Thread-local handshakes

[Doerr, Martin]

Hi,

I have disabled ThreadLocalHandshakes by default on linux 32 bit.
After some performance measurements, I have also switched it off on Windows 32 bit if the server compiler is not active (arguments.cpp) which is the default.
C1 performance is affected if enabled. C2 and tiered performance look ok.

So on 32 bit, ThreadLocalHandshakes are only used on Windows when enabling server mode with this updated version.

Please review:
http://cr.openjdk.java.net/~mdoerr/8195112_x86_local_poll/webrev.01/

@Robbin: I guess the submission forest is not helpful for 32 bit?
Will I still need a sponsor for it?

Best regards,
Martin


-----Original Message-----
From: Andrew Haley [mailto:aph at redhat.com] 
Sent: Donnerstag, 8. Februar 2018 17:28
To: Doerr, Martin <martin.doerr at sap.com>; David Holmes <david.holmes at oracle.com>; Robbin Ehn <robbin.ehn at oracle.com>; hotspot-runtime-dev at openjdk.java.net
Subject: Re: RFR(M): 8195112: x86 (32 bit): implementation for Thread-local handshakes

On 08/02/18 13:04, Doerr, Martin wrote:
> Are you planning to fix it soon?
> If so, we can delay my change until it was pushed.

I was, but I keep getting interrupted by urgent things.

> Otherwise, we can keep ThreadLocalHandshakes off by default on linux x86 32 bit.
> That would be ok for us, too. We'd just like the feature to be available.

Sure, do that.  Thanks.

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