<div dir="ltr"><div dir="ltr"><br></div><br><div class="gmail_quote"><div dir="ltr" class="gmail_attr">On Tue, Feb 28, 2023 at 11:06 AM Thomas Stüfe <<a href="mailto:thomas.stuefe@gmail.com">thomas.stuefe@gmail.com</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><div dir="ltr"><div dir="ltr"><br></div><br><div class="gmail_quote"><div dir="ltr" class="gmail_attr">On Sun, Feb 26, 2023 at 6:09 AM <<a href="mailto:mark.yagnatinsky@barclays.com" target="_blank">mark.yagnatinsky@barclays.com</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><div>
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<p class="MsoNormal">I saw this JEP draft today: <a href="https://openjdk.org/jeps/8303167" target="_blank">
https://openjdk.org/jeps/8303167</a>. It suggests deprecating the 32-bit Windows port of OpenJDK.<u></u><u></u></p>
<p class="MsoNormal">And even though it’s “just a draft” it does mention Java 21 (which is pretty soon), so I thought I might as well put in my “two cents” now instead of waiting to see whether or not this ends up going anywhere.<u></u><u></u></p>
<p class="MsoNormal">The draft is written as though the (primary?) purpose of the port is to support running Java on 32-bit versions of Windows.<u></u><u></u></p>
<p class="MsoNormal">Those are indeed very rare, and getting even rarer. But I appreciate the 32-bit builds even though I haven’t run a 32-bit version of Windows in ages.<u></u><u></u></p>
<p class="MsoNormal">Unlike MacOS, it is possible (and effortless) to run 32-bit executables on 64-bit Windows. There are at least 2 reasons to do so:<u></u><u></u></p>
<p class="MsoNormal">The obvious reason is that maybe someone has some native code they’re calling via JNI, and they don’t have a 64-bit version handy.<u></u><u></u></p>
<p class="MsoNormal">The other reason is perhaps less obvious, and perhaps I’m the only person in the world who considers this a “reason” at all, but it motivated me to write this email so here it is:<u></u><u></u></p>
<p class="MsoNormal">The restriction to 32-bits is pretty effective as a poor man’s substitute for a proper sandbox.<u></u><u></u></p>
<p class="MsoNormal">For example, the draft JEP talks about Project loom, a topic near and dear to me. When I first heard of Project loom, I wanted to run two silly experiments.<u></u><u></u></p>
<p class="MsoNormal">The first experiment was to launch as many “platform” threads as I could, and thus get a feel for how much they “cost”. The second experiment was to do the same for “virtual” threads.<u></u><u></u></p>
<p class="MsoNormal">I actually carried out the first experiment, on a 32-bit JVM. I did not dare to try the same experiment on a 64-bit JVM.<u></u><u></u></p>
<p class="MsoNormal">The reason is that I knew that with a 32-bit JVM, I would run out of address space before anything bad happened.<u></u><u></u></p>
<p class="MsoNormal">But if I tried the same thing with a 64-bit JVM, then for all I know I might bring my poor laptop to its knees and might even be forced to restart.<u></u><u></u></p>
<p class="MsoNormal">I’ve been eagerly awaiting Alexey Shipilev’s 32-bit port (is anyone else besides him working on this?) ever since then so I could try the “loom” part of the experiment.<u></u><u></u></p>
<p class="MsoNormal">I’ll be a bit disappointed if it never appears.<u></u><u></u></p>
<p class="MsoNormal"><u></u> <u></u></p>
<p class="MsoNormal">Anyway, that’s my two cents; thanks if you read this far.</p></div></div></div></blockquote><div><br></div><div>I agree that the JEP description is misleading; as you wrote, Windows 11 is able to run 32-bit processes.<br></div><div><br></div><div>Note that another advantage of 32-bit ports is that they can save quite a bit of memory if footprint is dominated by native memory and not java heap. That may not matter so much for Windows though.<br></div><div><br></div><div>Cheers, Thomas<br></div><div><br></div><div><br></div></div></div></blockquote><div><br></div><div>One small plus of getting rid of the 32-bit windows port would be that we could remove the specifiers for calling conventions (__cdecl and friends) and JNICALL.<br></div><div><br></div><div><br></div><div> </div></div></div>