asciidoctorj-pdf is very slow compared to conversion using fop

[david0]

First of all, thanks for the great work on asciidoctor(j)(-pdf)!

We are using asciidoctor-pdf to convert our documents, but are not really satisfied with the performance.
E.g. converting a 24 Page PDF (2 PNG, 2 SVG, 15 small xmls highlighed via rouge, some tables):

• asciidoctorj -> docbook -> fop -> pdf takes around 3 seconds
• asciidoctorj-pdf takes 15-20 seconds (The same document with cruby asciidoctor-pdf takes around 5 seconds to convert)

Is there anyway to improve the performance?

[david0]

Any idea why its so much slower? I really prefer asciidoctor-pdf, but we now have documents that take 10min to render...

[robertpanzer]

I guess an difference of 10s between asciidoctor-pdf and asciidoctorj-pdf can be expected since starting up the VM and the jruby runtime takes a bit of time.
Do you also see a big difference between the 2 for your larger documents that take 10 or 20 minutes to convert?

[david0]

The numbers are for a running JVM (GUI application). The 10min are from my collegues PC (windows..). I tried the same document on my MacBook:

• asciidoctorj -> docbook -> fop: 45s
• asciidoctorj-pdf: 130s
• asciidoctor-pdf: 35s

[mojavelinux]

I've seen several reports of AsciidoctorJ PDF being much slower on Windows (particularly from GUI applications). This very likely stems from an issue in JRuby, but one we don't yet understand. It's unlikely that it has anything to do with Asciidoctor itself.