[EXTERNAL] Re: Proposed JEP - Deprecate the Windows x86-32 Port

[Alex Buckley]

One last try to reach George Adams with comments on his JEP.

The mail below is also linked in a comment from the JEP (JDK-8303167).

Alex

On 3/3/2023 9:53 AM, Alex Buckley wrote:
> Hi George,
> 
> A couple of stylistic points on the JEP:
> 
> 1. Goals and Non-Goals usually appear before Motivation, e.g., as done 
> in JEP 362.
> 
> 2. In Alternatives, there is a paragraph about "It is also known that 
> 32-bit JVMs on Windows ...". This paragraph describes what a user could 
> do if this JEP proceeds, but Alternatives is usually about what the JEP 
> author could do instead the thing they just spelled out in the Description.
> 
> I recommend moving the paragraph to Risks & Assumptions, where you 
> already have a user story about WOW64. You could say something like the 
> text below. I made numerous edits for tone (I thought "in the wild" was 
> a bit flippant) and for clarity (there was an "older" and "newer" theme 
> going on that I thought unnecessary) and most importantly to spell out 
> the assumption.
> 
> -----
> It is known that 32-bit JVMs on Windows are still used due to 
> integration with 32-bit DLLs. These users cannot migrate directly to 
> 64-bit JVMs, because a 64-bit process on Windows cannot load a 32-bit 
> DLL. This JEP assumes that these users can continue to run a 32-bit JVM 
> to integrate with these native libraries, and expose their functionality 
> over some form of remote API that can be consumed by code in a 64-bit 
> JVM, within the same environment.
> -----
> 
> Alex
> 
> On 3/3/2023 2:43 AM, George Adams wrote:
>> Thank you so much for the feedback that everyone has provided so far. 
>> I have pushed a handful of changes to the JEP draft to help clarify 
>> some points. Most notably, this JEP does not intend to deprecate any 
>> other x86_32 ports.
>>
>> Thanks
>>
>> George Adams
>>
>> *From: *Glavo <zjx001202 at gmail.com>
>> *Date: *Wednesday, 1 March 2023 at 12:08
>> *To: *Alan Bateman <Alan.Bateman at oracle.com>
>> *Cc: *George Adams <George.Adams at microsoft.com>, 
>> jdk-dev at openjdk.java.net <jdk-dev at openjdk.java.net>
>> *Subject: *[EXTERNAL] Re: Proposed JEP - Deprecate the Windows x86-32 
>> Port
>>
>>
>>
>> You don't often get email from zjx001202 at gmail.com. Learn why this is 
>> important <https://aka.ms/LearnAboutSenderIdentification>
>>
>>
>>
>> I have seen many Intel Celeron N/J machines with memory <4GiB. 
>> Although x86-32 is old, its non-heap memory footprint is lower, so it 
>> works better under resource constraints.
>>
>> And although Windows 11 does not provide 32-bit images, as far as I 
>> know, Microsoft does not plan to give up support for running 32-bit 
>> programs on 64-bit systems.
>>
>> 32-bit programs are still an important part of Windows, a large number 
>> of programs are still 32-bit.
>>
>> For a considerable number of client applications, upgrading to 64-bit 
>> has only negative benefits.
>>
>> They only need a little memory and are not sensitive to performance.
>>
>> What will 64-bit bring to them? Higher resource consumption and poor 
>> compatibility (cannot run on x86-32 or Windows 10 on Arm systems)
>>
>> I know that maintaining a port requires a lot of manpower, so I can't 
>> ask you to do anything. But I really hope it will continue to be 
>> maintained.
>>
>> On Tue, Feb 28, 2023 at 3:15 AM Alan Bateman <Alan.Bateman at oracle.com 
>> <mailto:Alan.Bateman at oracle.com>> wrote:
>>
>>     On 27/02/2023 11:04, George Adams wrote:
>>
>>         Hi all,
>>
>>         I’ve been asked to socialize my proposed JEP to deprecate the
>>         Windows x86-32 port on this mailing list.
>>
>>         A link to the draft JEP can be found here:
>>         https://bugs.openjdk.org/browse/JDK-8303167
>>         
>> <https://nam06.safelinks.protection.outlook.com/?url=https%3A%2F%2Fbugs.openjdk.org%2Fbrowse%2FJDK-8303167&data=05%7C01%7CGeorge.Adams%40microsoft.com%7C645a895d36614b8ebfa408db1a4db724%7C72f988bf86f141af91ab2d7cd011db47%7C1%7C0%7C638132693333901376%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000%7C%7C%7C&sdata=DdaeznIQYUT4W4SQ4tlMDVUs3pQupv5mG2LrUYXN6J0%3D&reserved=0>
>>
>>         In summary, the main motivation for this JEP is that there is
>>         currently no implementation of JEP 436 (Virtual Threads)
>>         
>> <https://nam06.safelinks.protection.outlook.com/?url=https%3A%2F%2Fopenjdk.org%2Fjeps%2F436&data=05%7C01%7CGeorge.Adams%40microsoft.com%7C645a895d36614b8ebfa408db1a4db724%7C72f988bf86f141af91ab2d7cd011db47%7C1%7C0%7C638132693333901376%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000%7C%7C%7C&sdata=QD41i%2B7kj3j01c5%2B3b0pRSx6NKY751CUnfrele7Har0%3D&reserved=0> for 32-bit platforms and without a vendor stepping forward to implement this it's unlikely that OpenJDK will be able to continue supporting 32-bit architectures. Another motivation is that Windows 10 (the last Windows operating system to support a 32-bit installation) will reach EOL on October 14, 20251.
>>
>>     When you build JDK 19+ to target windows-x86 then it will use an
>>     alternative implementation of virtual thread that creates a kernel
>>     thread for each virtual thread. So it doesn't scale but it's good
>>     enough for Zero and ports that are a bit behind.
>>
>>     That said, it's a good topic to bring up. I don't expect dropping
>>     windows-x86 will remove the burden of keeping the x86_32 port
>>     working, to do that would require dropping linux-x86 too. So maybe
>>     the discussion should be broadened to ask if the time is approaching
>>     to remove the x86_32 port? At one point, one of the arguments to
>>     keep linux-x86 working was reconditioning older computers but I
>>     don't know if this is still the case. I see a mail to jdk-dev from
>>     Mark Yagnatinsky that talks about JNI libs or drivers that are
>>     32-bit only. There isn't much context but it would be surprising for
>>     something that is actively maintained to not have a 64-bit build in
>>     2023. He also mentions limiting resources but that may be a case
>>     where an OS container should be used. It might be that you expand
>>     the Motivation in draft JEP to cover these points.
>>
>>     -Alan
>>