8179527: Ineffective use of volatile hurts performance of Charset.atBugLevel()

[Kazunori Ogata]

Hi Alan,

I'm working on the JDK 10 source code, but I verified JDK 8 has the same 
code w.r.t. use of volatile.


Regards,
Ogata


Alan Bateman <Alan.Bateman at oracle.com> wrote on 2017/06/27 17:13:19:

> From: Alan Bateman <Alan.Bateman at oracle.com>
> To: Claes Redestad <claes.redestad at oracle.com>, "Langer, Christoph" 
> <christoph.langer at sap.com>, Kazunori Ogata <OGATAK at jp.ibm.com>, 
core-libs-
> dev <core-libs-dev at openjdk.java.net>, "nio-dev at openjdk.java.net" <nio-
> dev at openjdk.java.net>
> Cc: "ppc-aix-port-dev at openjdk.java.net" 
<ppc-aix-port-dev at openjdk.java.net>
> Date: 2017/06/27 17:13
> Subject: Re: 8179527: Ineffective use of volatile hurts performance of 
> Charset.atBugLevel()
> 
> On 27/06/2017 08:36, Claes Redestad wrote:
> >
> > The check of Charset.atBugLevel in checkName should no longer happen 
> > for the majority of situations, as that test is now only done if the 
> > charset name is "" (see 
> > https://bugs.openjdk.java.net/browse/JDK-8174831), 
> Kazunori's mail didn't mention the JDK build he is using, it may have 
> been JDK 8 rather than JDK 9.
> 
> > since what differs between 1.4 and 1.5 was apparently whether or not 
> > the empty string was to be accepted as a valid Charset...
> >
> > So yes, if we can get rid of the test altogether, we'll be even better 

> > off!
> JDK-4786884 is the original issue. If there was any code dependent on 
> the broken behavior in 1.4 then I would expect it should have been fixed 

> by now. So I think it can be removed.
> 
> -Alan
>