Unsafe vs MemorySegments / Bounds checking...

[Brian S O'Neill]

I'll try the latest JDK 24 build and report back. One thing that 
concerns me with the latest build is this error message when I enable 
large pages (which helps with performance):

[0.027s][error][cds] Failed to commit static  region #3 (Heap)
[0.027s][error][cds] Failed to read archived heap region into 
0x00000007ffe00000


On 2024-10-29 12:07 PM, Maurizio Cimadamore wrote:
> 
> On 29/10/2024 18:35, Brian S O'Neill wrote:
>> If you recall, I did send you a reproducer, and you did verify the 
>> regression. This is what led you to come up with a strategy to define 
>> a derived VarHandle. This helped somewhat, but you observed the 
>> inliner giving up when the code was embedded in a very large method. 
>> JDK 23 appears to have introduced a regression that has made this worse. 
> 
> The fact that you mention that 23 made it worse reminds me of [1], where 
> a fix in 23 created an issue for adapted memory access var handles.
> 
> If I recall correctly, the workaround we suggested was _also_ using 
> adapted var handles.
> 
> So I wonder if (a) you were already running into the issue in [1] and 
> (b) because of that JDK 23 made it worse for you.
> 
> Did you have a chance to try your project with the latest JDK 24 build? 
> Is the regression gone there? That would be useful to know regardless of 
> the wider discussion.
> 
> Maurizio
> 
> [1] - https://mail.openjdk.org/pipermail/panama-dev/2024- 
> September/020643.html
>