On 7/21/2021 4:08 PM, Michal Vlasák wrote:
On Wed Jul 21, 2021 at 3:57 PM CEST, Hans Hagen wrote:
even if one would handle bytes in the lua bytecode, the bytecode itself
is not portable (and i'm not even sure how luajit stuff fits in because
luajit is even more platform specific
LuaJIT is actually really nice in this regard:
"The generated bytecode is portable and can be loaded on any
architecture that LuaJIT supports, independent of word size or
endianess. However the bytecode compatibility versions must match."
Ok, btw, these bytecode compatibility versions are not guaranteed the
same within intermediate updates (so for instance during the 5.4 dev
stage they changed .. i actually took care of that but didn't want to
patch the official code - with a sub number - any more so i dropped that)
one observation is that using macros instead of functions for
performance makes little sense in a program like tex where one jumps
over memory space all the time (compilers are quite okay in optimizing),
but there can be differences between versions of e.g. gcc
I think that modern compilers are good with inlining, one can get more
espcially when functions are marked static. So I incline towards
functions rather than macros.
also, local optimization is better
in general, loss of performance in a tex engine is more due to the way
macros are composed (or user styles for that matter)
another one is the performance of the console, i.e. kind of font,
buffer, refresh delays defaults (i noticed that linux has large delays
so that's the fastest, the new windows terminal is also fast) .. now
that one is really measureable .. just try to run with piping the log
to a file (all understandable) .. squeezing microseconds out of the
binary can easily be nilled that way
Yeah, you are right, even for 18 lines of console output I mesaure more
noticable difference than with the mallocs and byte swapping.
it has to do with the fact that tex outputs on a char by char basis with
different criteria for log and console, and most consoles accumulate
some before flushing, sometimes upto 200 ms
the old windows console output per-char so that one was hurt most, but
there were plenty ways around that; on osx fancy font features in a
console could also work out bad
Hans
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