[tex4ht] "page is empty" messages. But nothing seems wrong in the HTML

[Karl Berry]

Hi Nasser,

    The above phase of the compile is the one that takes for ever.

I'm not surprised that running dvisvgm on a 13000+ page DVI file (even
if many pages are empty) takes a long time. Let's see, 5515 seconds
means it's doing better than a page in a half-second, it just adds up to
90+ minutes in total :(.

The best way forward I can think of is if you can grab the DVI file
which is being given to dvisvgm. Then we could show it to Martin G
(dvisvgm author) and see if he can suggest any way to speed it up.

Also, once the input to dvisvgm is available, dvisvgm could be run under
a profiler to discern if there is some "inner loop" that can be
optimized.

Also, you're on cygwin, right? I wonder if the cygwin layer over Windows
is adding to I/O access times; I/O is almost surely a big part of the
time being taken. Just writing 13000+ files probably takes a while.
If we can try running the input on gnu/linux or other envs, we could
know if that's an issue ... --best, karl.