Re: [boost] [xpressive] Performance Tuning?

Subject: Re: [boost] [xpressive] Performance Tuning?
From: John Bytheway (jbytheway+boost_at_[hidden])
Date: 2009-07-18 15:51:19

OvermindDL1 wrote:
<snip>
> As stated, I have heard that Visual Studio handles template
> stuff like Spirit better then GCC, so I am very curious how GCC's
> timings on this file would be.

Alas, gcc doesn't do so well.  I had to make a few tweaks to your code
(you typedefed int64_t at global scope which clashes with the one in the
C library headers, and you used an INT64 macro which doesn't exist here)
but then I got a very long error ending with this:

.../boost-trunk/boost/proto/transform/call.hpp:146: internal compiler
error: Segmentation fault

I guess the metaprogramming is too much for it :(.

That was with -O3 -DNDEBUG -march=native and gcc version:
gcc (Gentoo 4.3.3-r2 p1.2, pie-10.1.5) 4.3.3

So then I tried icc 10.1 (essentially same options) which takes over a
minute to compile this, but does succeed.  With that I got:

$ ./price-icc
Loop count:  10000000
Parsing:  42.5
xpressive:  27.4704
spirit-quick(static):  1.58132
spirit-quick_new(threadsafe):  1.52971
spirit-grammar(threadsafe/reusable):  1.64666

which are much the same as your results (except ~1.7 times faster all
round), but the Parsing result is obviously meaningless and the
xpressive also dubious because of lexical_cast.

I then tried with icc's inter-procedural optimisations turned on too,
which improves the xpressive code significantly, but doesn't obviously
affect spirit:

$ ./price-icc-ipo
Loop count:  10000000
Parsing:  42.5
xpressive:  17.3577
spirit-quick(static):  1.52487
spirit-quick_new(threadsafe):  1.51834
spirit-grammar(threadsafe/reusable):  1.65164

Finally I used static linking, and the xpressive time improved again,
and maybe the others a little.  This surprised me.

$ ./price-icc-ipo-static
Loop count:  10000000
Parsing:  42.5
xpressive:  12.6157
spirit-quick(static):  1.49887
spirit-quick_new(threadsafe):  1.48146
spirit-grammar(threadsafe/reusable):  1.62731

John Bytheway