[aarch64-port-dev ] RFR (XS) 8252096: Shenandoah: adjust SerialPageShiftCount for x86_32 and JFR

[Aleksey Shipilev]

On 8/27/20 7:47 AM, Aleksey Shipilev wrote:
> On 8/27/20 7:38 AM, Andrew Hughes wrote:
>> How did you find the correct value? I've been considering backporting
>> https://bugs.openjdk.java.net/browse/JDK-8152358 as it makes the assert
>> print the expected value.
> 
> I printed out sizeof(JavaThread) in multiple build configurations, and discovered that with both JFR
> and Shenandoah it trips over 1024. Which means the expected count is log2_intptr(sizeof(class
> JavaThread)) - log2_intptr(64) = log2(2^10) - log2(2^6) = 4. That is basically +1 to current value.
> 
>> Anyway, if it only applies when Shenandoah + JFR are in operation, it explains
>> why Azul have not seen it on upstream 8u. Change looks good to me and it will
>> be good to get this fixed and JFR enabled on our x86 builds.
> 
> Yes.

Pushed:
  http://hg.openjdk.java.net/aarch64-port/jdk8u-shenandoah/hotspot/rev/04d10e4240b9

-- 
Thanks,
-Aleksey