RFR: 8150044: Generate classlists at build-time
Erik Joelsson
erik.joelsson at oracle.com
Wed May 4 14:24:49 UTC 2016
Depends on which OS you are using. You need version 2.69, which is the
latest. On linux, "apt-get/yum install autoconf" should do the trick
unless your distribution is ancient. On windows add autoconf through the
cygwin installer. On mac I think "brew install autoconf" is easiest if
you are into that. If all else fails, downloading the source [1] and
building is pretty easy and straightforward too.
/Erik
[1] http://ftp.gnu.org/gnu/autoconf/autoconf-2.69.tar.gz
On 2016-05-04 16:13, Jim Laskey (Oracle) wrote:
> Correct. How do I set up autogen so I can apply these changes?
>
>
>> On May 4, 2016, at 11:11 AM, Erik Joelsson <erik.joelsson at oracle.com> wrote:
>>
>> Build changes look ok to me, but I also helped write most of them.
>>
>> This certainly adds some build complexity and might seem overly so for just this optimization. As I understand it, the plan is to expand this build time profiling concept to generate more profile data that can be used by for example jlink plugins.
>>
>> /Erik
>>
>> On 2016-05-04 15:36, Claes Redestad wrote:
>>> Hi,
>>>
>>> please review this change to generate classlists at build-time
>>>
>>> bug: https://bugs.openjdk.java.net/browse/JDK-8150044
>>>
>>> webrevs:
>>> top: http://cr.openjdk.java.net/~redestad/8150044/top.01/
>>> jdk: http://cr.openjdk.java.net/~redestad/8150044/jdk.01/
>>> hotspot: http://cr.openjdk.java.net/~redestad/8150044/hotspot.01/
>>>
>>> The implementation generates an interim image consisting of a minimal
>>> set of modules, then use this to run a small generator program to
>>> load common utilities and facilities and dump the result of this to a
>>> classlist that is then bundled with the final images.
>>>
>>> The smaller number of classes on the default classlist (~1100 instead
>>> of ~2500) requires some adjustment to the metaspace defaults.
>>>
>>> This achieves the following:
>>>
>>> - Removes a manual, error-prone process to update the versioned
>>> classlists
>>> - Ensures the classlists shipped with the JDK/JRE is up to date
>>> with recent JDK changes, e.g., when moving classes from sun.* to
>>> jdk.internal.*
>>> - Automatically picks up and incorporates the output of jlink plugins
>>> such as GenerateJLIClassesPlugin into the classlist
>>> - Supports cross-compilation build targets, although it runs using a
>>> build JDK that can run on the host platform to generate such
>>> classlists (this isn't ideal, but no worse than the current
>>> situation, where the versioned classlist for the host platform is
>>> simply copied to the cross-compiled target)
>>>
>>> There are a few concerns/drawbacks:
>>>
>>> - It does add complexity to the build, and concern has been voiced that
>>> this would adversely affect build times. However, I'm happy to say
>>> that on my machine build times are roughly the same:
>>>
>>> Before:
>>> real 2m37.303s
>>> user 35m33.576s
>>> sys 3m46.476s
>>>
>>> After:
>>> real 2m36.168s
>>> user 35m31.232s
>>> sys 3m52.268s
>>>
>>> (real time varies ± 5s from build to build)
>>>
>>> - Startup on the specific applications we've used to generate the
>>> classlists for previously suffer small regressions. These are
>>> specifically rather dated AWT and Swing-based applications. OTOH,
>>> startup characteristics generally improve on other applications
>>> (minimal VM, jetty, etc...)
>>>
>>> Testing: JPRT -testset hotspot
>>>
>>> Thanks!
>>>
>>> /Claes
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