Minimum stack size..

[Volker Simonis]

Hi Steve,

I suspected you'll come back with this issue, especially after I
pretended that it will be easy to fix :)

You're actually right, the minimum stack size is computed at VM
startup from various other parameters one of which is the OS page
size.
It's a long standing problem in HotSpot that at various places it is
assumed that the default OS page size is 4k. That's obviously not true
anymore (on Linux/PPC it's usually 64k) and that leads to such kind of
errors (if you'd divide 1920k by 16 you'd get 120k which would be
reasonable).

We've already changes this behavior in our SAP JVM  but that's quite a
large shared code change which we've omitted from the port so far.
Please let me discuss this with Goetz tomorrow to see haw we can fix
this for our port - but I think it would be reasonable to fix it in
the HotSpot and not in the test.

Regards,
Volker

On Wed, Apr 17, 2013 at 6:30 PM, Steve Poole <spoole at linux.vnet.ibm.com> wrote:
>
> hi.  we are  working though the last remaining jtreg test failures for
> PPCAIX.
>
> I have some that are failing on Linux PPC as the  test explicitly sets the
> minimum stack size  to "-Xss256k" . The VM then fails to launch with the
> usual error
>
> The stack size specified is too small, Specify at least 1920k
>   Error: Could not create the Java Virtual Machine.
>   Error: A fatal exception has occurred. Program will exit.
>
>
>
> So I can adjust the stack size in the testcases to suit this number or
> remove it altogether.  But...
>
> 1 - This number of 1920k seems a trifle  excessive  - is it something I'm
> doing wrong in building hotspot or is this actually a reasonable number?
> 2 - Since it seems from reading the hotspot code that this number is
> calculated is there any Java API I can use to get this number so I can make
> the tests more flexible?
>
>
> Cheers
>
>
>