The Perl Compiler
rurban - Reini Urban <br> Graz, Austria
rurban maintains cygwin perl since 5.8.8 and 3-4 modules, guts, B::* => 5.10
Mostly doing LISP Perl and PHP, and support for custom HW, windows + linux + real-time systems in real-life. Coding in winter, surfing in summer.
1995 first on CPAN with the perl5.hlp file and converter for Windows.
Started 1995 by Malcom Beattie, abandoned 2007 by p5p, revived 2008 by me
Very dynamic language. eval "require $foo;" -> which packages?
In the Perl Compiler suite B::C are three seperate compilers:
perl toke.c/op.c - B::C - perl op walker run.c
Eliminate the whole parsing and dynamic allocation time.
After compilation walk the "op tree" - run.c
1. The op tree is not a "tree", it is reduced to a simple linked list of ops. Every "op" (a pp_<opname> function) returns the next op.
pp_<opname>
2. PERL_ASYNC_CHECK is called after every single op.
Normal Perl functions start at INIT, after BEGIN and CHECK. <br> The O modules start at CHECK, and skip INIT.
The B Compilers, invoked via O, freeze the state in CHECK, and invoke then the walker.
$ perl -MO=C,-omyprog.c myprog.pl <br> $ cc_harness -o myprog myprog.c <br> $ ./myprog
</font>
<br><br><br>
5.6.2 and 5.8.9 non-threaded B::C are quite usable and have the least known bugs, but 5.10 and 5.12 became also pretty stable now.
See testsuite and STATUS
Which software is compiler critical?
Execution time is the same (sans B::CC)
Startup time is radical faster
Startup time is radical faster.
Web Apps with fast response times -
1 sec more or less => good or bad software
Optimise static initialization - strings and arrays
non-threaded ! +10-20% performance
ltrace reveils Gthr_key_ptr, gv_fetchpv, savepvn, av_extend and safesysmalloc as major culprits, the later three at startup-time.
ltrace
Gthr_key_ptr
gv_fetchpv
savepvn
av_extend
safesysmalloc
common constant strings with gcc -Os => automatically optimised
av_extend - run-time malloc => static arrays ?
static arrays are impossible if not Readonly
can not be extended at run-time, need to be realloc'ed into the heap.
pre-allocate faster with -fav-init or -O3
at least this is the idea. Same for hashes (nyi).
cPanel has used B::C compiled 5.6 for a decade, and wants to switch to 5.8.9 (or later).
cPanel offers web hosting automation software that manages provider data, domains, emails, webspace. A typical large webapp. Perl startup time can be too slow for many AJAX calls which need fast initial response times.
Larger code base => more significant startup improvements
Web Service Daemon <br> Resident Size (perlcc) 9072 <br> Resident Size (perl) 9756 <br> <br> DNS Settings Client <br> Startup Time (perl) 0.074 <br> Startup Time (perlcc) 0.021 <br> <br> HTML Template Processor <br> Startup Time (perlcc) 0.037 <br> Startup Time (perl) 0.695 <br>
2010: Find and fix all remaining bugs
2010: Faster testsuite (Now 8 min - 40min - 2 days)
8 min - 40min - 2 days
2011: CC type and sub optimisations
2012: CC unrolling => jit within perl (perl -j)
perl -j
Emit parrot pir.
run-time ops vs compile-time ...
dynamic range 1..$foo
goto/next/last $label
Undetected modules behind eval "require": <br> use -uModule to enforce scanning these
run-time ops vs compile-time<br> BEGIN blocks only compile-time side-effects.
BEGIN { <br> use Package; # okay <BR> chdir "dir"; # not okay. <BR> # only done at compile-time, not at the user<BR> print "stuff"; # okay, only at compile-time <BR> eval "what"; # hmm; depends <br> }
Move eval "require Package;" to BEGIN
Custom sort BLOCK is buggy, wrong queue implementation
Custom sort BLOCK is buggy, wrong queue implementation, causing an endless loop
sort { $a <=> $b } <br> <small>is optimised away, ok</small><br><br> sort { $hash{$a} <=> $hash{$b} } <br> <small>maybe?</small><br><br> sort { $hash{$a}->{field} <=> $hash{$b}->{field} } <br> <small>for sure not</small>
user make test (via cpan):
35x bytecode + c -O0 - O4 + cc -O0 - O2
=> 8 min
author make test:
35x bytecode + c -O0 - O4 + cc -O0 - O2 (8 min)
modules.t top100 (16 min)
+ testcore.t (16 min)
=> ~40 min
author make test 40 min
for 5-10 perls (5.6, 5.8, 5.10, 5.11 / threaded + non-threaded) 4*2=8
on 5 platforms (cygwin, debian, centos, solaris, freebsd)
=> 26 h (8*5*40 = 1600min) = 1-2 days, similar to the gcc testsuite.
top100 modules?
See webpage or svn repo for results for all tested perls / modules
With 5.8 non-threaded 3 fails Attribute::Handlers B::Hooks::EndOfScope YAML MooseX::Types
With blead non-threaded 4 fails Attribute::Handlers File::Temp ExtUtils::Install
unpredictable results: e.g. threaded 5.10 39/98 (cygwin release) vs 3/80 (a test version) fails. Innocent change => fatal consequences.
What can we statically leave out per pp_?
Now: arguments passing, return values for 50% ops
Planned: more + direct xsub calls.
Now: Unroll for known static types pp_opname completely into simple arithmetic.
Known static types at compile-time? User declarations or Devel::TypeCheck
Currently:
my $E<lt>nameE<gt>_i; IV integer <br> my $E<lt>nameE<gt>_ir; IV integer in a pseudo register <br> my $E<lt>nameE<gt>_d; NV double
<hr>
Future ideas are type qualifiers such as <br> <code>my (int $foo, double $foo_d); </code>
or attributes such as <br> <code>my ($foo:Cint, $foo:Cintr, $foo:Cdouble);</code>
or MooseX::Types
http://search.cpan.org/dist/B-C/
http://code.google.com/p/perl-compiler/
Planned:
http://compiler.perl.org/
mailto:compiler@perl.org
To install B::C, copy and paste the appropriate command in to your terminal.
cpanm
cpanm B::C
CPAN shell
perl -MCPAN -e shell install B::C
For more information on module installation, please visit the detailed CPAN module installation guide.