Need help to understand TLS behavior

[David Holmes]

What is TLS in this context?

Thanks,
David

On 14/12/2015 10:34 PM, cheleswer sahu wrote:
> Hi,
>
> I am investigating an issue, in which test with TLS size set to 32K is
> failing with StackOverFlowError. During investigation I found the below
> code
> http://hg.openjdk.java.net/jdk8u/jdk8u/jdk/file/tip/src/solaris/classes/java/lang/UNIXProcess.java
>
>
>   ThreadFactory threadFactory = grimReaper -> {
>                  // Our thread stack requirement is quite modest.
>                  Thread t = new Thread(systemThreadGroup, grimReaper,
>                                        "process reaper", 32768);
>
> Here reaper thread is created with fixed stack size "32768 ", which
> causes StackOverFlowError  when TLS is set to 32k around.
> If I remove this fixed size and make it default, test works fine.
>
> Thread t = new Thread(systemThreadGroup, grimReaper,
>                                        "process reaper");
>
> I have run several test with TLS size 32k , 64k ,128k and more .
> The interesting part, it works well with 64k and 128k TLS size but not
> with 32k.
> So my questions are as follows:
>> What is the motivation behind the fixed thread stack size ?
>> will it be ok to replace the fixed stack size with default or stack
> size setting is platform sensitive?
>> How TLS sizes are interpreted internally, which allows 64k and 128k
> to work but not to 32k ?
>
> I would really appreciate, if anyone have any opinion on this.
>
> Regards,
> Cheleswer
>
>
>