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<p class="MsoNormal"><span lang="EN-GB">Hi all,<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB">Currently, the Unified Logging framework defaults to three decorators (uptime, level, tags) whenever the user does not specify otherwise through -Xlog. This
</span><span lang="EN-GB">results</span><span lang="EN-GB"> sometimes inconvenient when specific users with some predefined needs do not want those tags. For example, C2 developers would rather not see those defaults in cases such as jit+inlining, but also
do not want to specify so every time they run -Xlog.<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB">One solution for this is found in this PR:
<a href="https://github.com/openjdk/jdk/pull/20988">https://github.com/openjdk/jdk/pull/20988</a>. It can be considered as a “flavoured” version of the existing default decorators and in no way it will override anything user-specified. Also, decorators will
still be consistent throughout an output device (i.e., no different decorators “mixed in”).<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB">However, upon recent talks with different teams this approach may be too flexible/powerful. The ability of specifying LogSelection-bound default decorators may result in a situation where defaults for A+B and C+D have
been specified, and a user selects -Xlog:A+B,C+D. In that case, the union of the prespecified defaults is taken, which may not be what the end user wants (and might result in too many decorators).<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB">Actually, the main use case for this that I know as of now is C2 developers and the wish to not see decorators for some defined log selections. With this in mind, I have reduced the original idea to a feature where only
the default decorators are not shown if we get a positive match with a prespecified list throughout the entire user log selection list (i.e.:<o:p></o:p></span></p>
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<li class="MsoListParagraph" style="margin-left:0cm;mso-list:l0 level1 lfo1"><span lang="EN-GB">If there is a default for A+B and the user specifies -Xlog:A+B,C+D, he will still get the default decorators<o:p></o:p></span></li><li class="MsoListParagraph" style="margin-left:0cm;mso-list:l0 level1 lfo1"><span lang="EN-GB">If there is a default for A+B and the user specifies -Xlog:A+B, no default decorators will be supplied).<o:p></o:p></span></li></ul>
<p class="MsoNormal"><span lang="EN-GB"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB">Before scraping the original idea and moving on with this one (which will not change anything as it is right now, except for the really specific uses like C2 jit+inlining that may be decided),
<b>I wanted to get a broader idea of people’s opinions on this, as well as other use cases for this behaviour.<o:p></o:p></b></span></p>
<p class="MsoNormal"><b><span lang="EN-GB"><o:p> </o:p></span></b></p>
<p class="MsoNormal"><span lang="EN-GB">Many thanks,<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB">Antón<o:p></o:p></span></p>
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