I wrote: > ... I wonder whether Apple are using more > aggressive optimization flags than other people. OTOH, while it would > not surprise me if Apple put some work into making zlib go fast, it > seems less likely that they'd expend effort or risk on xsltproc.
I checked Fedora 26 and found that it's using an identical source version of xsltproc: $ xsltproc --version Using libxml 20904, libxslt 10129 and libexslt 817 xsltproc was compiled against libxml 20904, libxslt 10129 and libexslt 817 libxslt 10129 was compiled against libxml 20904 libexslt 817 was compiled against libxml 20904 Its time to build the HTML docs ... 46 seconds. This is on a machine intermediate in speed between the Sierra and High Sierra machines whose timings I quoted before. So we can definitively discard the idea that Apple sprinkled any magic pixie dust on their xsltproc build. Your MacPorts build is the outlier, leaving us with the theories that it was built at -O0 or there's a performance bug in the newer source releases. I have no doubt that xmlsoft.org would be interested if you can narrow it down to the latter. regards, tom lane