Re: 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