RFR: 8349638: Build libjdwp with SIZE optimization

[Matthias Baesken]

On Wed, 19 Feb 2025 17:12:55 GMT, Chris Plummer <cjplummer at openjdk.org> wrote:

> I'm not sure how the decision was made to go with LOW for libjdwp. 

>From what I heard from Magnus, those settings were done ages ago , before recent compiler switches and even before the current build system was introduced.

We switched in the meantime from gcc 11.3 to gcc 13.2 in our buildenv .
libjdwp.so / debuginfo is  with opt
SIZE -  264K  /  1.7M 
current NORM/LOW  - 304k / 1.9M

LTO with the patch as given above - 300K
LTO and also BUILDLIBJDWP opt set to HIGH - 328K

So for gcc13.2 with lto enabled (300K) , the lib size gets slightly larger compared to gcc 11.3 with lto enabled (280K).

> It seems LTO would be good to enable regardless of the optimization level. 

Unfortunately I think we do not have many benchmarks for the JDK native libs, or maybe I am not aware of them ?

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PR Comment: https://git.openjdk.org/jdk/pull/23563#issuecomment-2671513995