RFR: JDK-8244036 Refresh SetupJavaCompilation, and remove support for sjavac

[Magnus Ihse Bursie]

On 2020-04-30 15:07, Magnus Ihse Bursie wrote:
> On 2020-04-30 14:55, Florian Weimer wrote:
>> * Magnus Ihse Bursie:
>>
>>> The code for setting up Java compilation has long been quite hard to
>>> understand, and has a tricky API. Part of this is due to the support 
>>> for
>>> the sjavac ("smart javac") system. We do not use sjavac anymore, and it
>>> has not been tested for long. Part of the sjavac effort was extracted
>>> into the "depend" javac plugin, and another part ended up as the java
>>> server, both of which we still use.
>> This commit:
>>
>> # HG changeset patch
>> # User ihse
>> # Date 1588142957 -7200
>> #      Wed Apr 29 08:49:17 2020 +0200
>> # Node ID a8e4856be54f73225780a56b2b6ee9cc1e12ab8f
>> # Parent  f53590a82709caf92213106954eab2bdc97cc498
>> 8244036: Refresh SetupJavaCompilation, and remove support for sjavac
>> Reviewed-by: erikj
>>
>> appears to have regressed build time (“time make jdk-image”) by
>> roughly one third, on an x86-64 machine with 8 cores/16 threads.
>> The configure arguments are “--with-zlib=system --with-lcms=system”,
>> so nothing sjavac-related as far as I can see.
>>
>> Is this expected?
> No, that is very much not expected. :-(
>
> I made sure that no build performances were measured on my system, 
"... no build performance *regressions* ..."

/Magnus

> and since I saw no such indication, I did not make any more systematic 
> analysis.
>
> What is the difference if you run with or without the javac server? 
> Both prior to and after this commit. Do you have any numbers to share?
>
> /Magnus