[aarch64-port-dev ] Question about JVM option "-XX:+UseBarriersForVolatile" usage in aarch64.

[Xiaohong Gong]

Hi Andrew,

Thanks for your replying! We will take a look and find a better way for it.

Thanks,
Xiaohong Gong

-----Original Message-----
From: Andrew Haley <aph at redhat.com> 
Sent: Monday, March 30, 2020 5:56 PM
To: Xiaohong Gong <Xiaohong.Gong at arm.com>; aarch64-port-dev at openjdk.java.net
Cc: nd <nd at arm.com>
Subject: Re: [aarch64-port-dev ] Question about JVM option "-XX:+UseBarriersForVolatile" usage in aarch64.

On 3/30/20 10:20 AM, Xiaohong Gong wrote:
> So my question is: what does the main usage of the option 
> "-XX:+UseBarriersForVolatile" in real applications? Do we need to concern the issues with it? If we do, so maybe the issue is valuable to be fixed.
> I also created a JBS here: https://bugs.openjdk.java.net/browse/JDK-8241137.

There is no usage of "-XX:+UseBarriersForVolatile" in real applications.
Any flags of this kind are dangerous because they tend to break over time because they are not tested.

I was thinking we could make this a diagnostic-only flag, but perhaps it should be removed altogether. Patches welcome.

--
Andrew Haley  (he/him)
Java Platform Lead Engineer
Red Hat UK Ltd. <https://www.redhat.com> https://keybase.io/andrewhaley
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