in reply to Re: undef quite slow?
in thread undef quite slow?

perl -V output: 
Summary of my perl5 (revision 5 version 8 subversion 4) configuration:
  Platform:
    osname=linux, osvers=2.4.20-28.7bigmem, archname=i686-linux
    uname='linux bulldog 2.4.20-28.7bigmem #1 smp thu dec 18 11:04:21 
+est 2003 i686 unknown '
    config_args='-de -Dinc_version_list=none -Dprefix=/usr/local/apps/
+perl-5.8.4'
    hint=recommended, useposix=true, d_sigaction=define
    usethreads=undef use5005threads=undef useithreads=undef usemultipl
+icity=undef
    useperlio=define d_sfio=undef uselargefiles=define usesocks=undef
    use64bitint=undef use64bitall=undef uselongdouble=undef
    usemymalloc=n, bincompat5005=undef
  Compiler:
    cc='cc', ccflags ='-fno-strict-aliasing -I/usr/local/include -D_LA
+RGEFILE_SOURCE -D_FILE_OFFSET_BITS=64 -I/usr/include/gdbm',
    optimize='-O2',
    cppflags='-fno-strict-aliasing -I/usr/local/include -I/usr/include
+/gdbm'
    ccversion='', gccversion='2.96 20000731 (Red Hat Linux 7.3 2.96-11
+3)', gccosandvers=''
    intsize=4, longsize=4, ptrsize=4, doublesize=8, byteorder=1234
    d_longlong=define, longlongsize=8, d_longdbl=define, longdblsize=1
+2
    ivtype='long', ivsize=4, nvtype='double', nvsize=8, Off_t='off_t',
+ lseeksize=8
    alignbytes=4, prototype=define
  Linker and Libraries:
    ld='cc', ldflags =' -L/usr/local/lib'
    libpth=/usr/local/lib /lib /usr/lib
    libs=-lnsl -lndbm -lgdbm -ldl -lm -lcrypt -lutil -lc
    perllibs=-lnsl -ldl -lm -lcrypt -lutil -lc
    libc=/lib/libc-2.2.5.so, so=so, useshrplib=false, libperl=libperl.
+a
    gnulibc_version='2.2.5'
  Dynamic Linking:
    dlsrc=dl_dlopen.xs, dlext=so, d_dlsymun=undef, ccdlflags='-Wl,-E'
    cccdlflags='-fpic', lddlflags='-shared -L/usr/local/lib'


Characteristics of this binary (from libperl):
  Compile-time options: USE_LARGE_FILES
  Built under linux
  Compiled at Apr 27 2004 21:32:07
  @INC:
    /usr/local/apps/perl-5.8.4/lib/5.8.4/i686-linux
    /usr/local/apps/perl-5.8.4/lib/5.8.4
    /usr/local/apps/perl-5.8.4/lib/site_perl/5.8.4/i686-linux
    /usr/local/apps/perl-5.8.4/lib/site_perl/5.8.4
    /usr/local/apps/perl-5.8.4/lib/site_perl
    .

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I don't think I can upgrade the libc on this machine. And I am not entirely sure what you mean by "with or without perl's malloc" - could you elaborate a bit on the pros and cons of that?

I've just tried it on a very differently configured machine (perl -V output for that one is below) and it doesn't seem to have the same problem, unfortunately the above configuration is what we use everywhere.

perl -V that works fine (this is the default perl for RedHat enterprise 3.0): 

Summary of my perl5 (revision 5.0 version 8 subversion 0) configuratio
+n:
  Platform:
    osname=linux, osvers=2.4.21-1.1931.2.393.entsmp, archname=i386-lin
+ux-thread-multi
    uname='linux por'
    config_args='-des -Doptimize=-O2 -g -pipe -march=i386 -mcpu=i686 -
+Dmyhostname=localhost -Dperladmin=root@localhost -Dcc=gcc -Dcf_by=Red
+ Hat, Inc. -Dinstallprefix=/usr -Dprefix=/usr -Darchname=i386-linux -
+Dvendorprefix=/usr -Dsiteprefix=/usr -Dotherlibdirs=/usr/lib/perl5/5.
+8.0 -Duseshrplib -Dusethreads -Duseithreads -Duselargefiles -Dd_dosui
+d -Dd_semctl_semun -Di_db -Ui_ndbm -Di_gdbm -Di_shadow -Di_syslog -Dm
+an3ext=3pm -Duseperlio -Dinstallusrbinperl -Ubincompat5005 -Uversiono
+nly -Dpager=/usr/bin/less -isr'
    hint=recommended, useposix=true, d_sigaction=define
    usethreads=define use5005threads=undef'
 useithreads=define usemultiplicity=
    useperlio= d_sfio=undef uselargefiles=define usesocks=undef
    use64bitint=undef use64bitall=un uselongdouble=
    usemymalloc=, bincompat5005=undef
  Compiler:
    cc='gcc', ccflags ='-D_REENTRANT -D_GNU_SOURCE -DTHREADS_HAVE_PIDS
+ -DDEBUGGING -fno-strict-aliasing -I/usr/local/include -D_LARGEFILE_S
+OURCE -D_FILE_OFFSET_BITS=64 -I/usr/include/gdbm',
    optimize='',
    cppflags='-D_REENTRANT -D_GNU_SOURCE -DTHREADS_HAVE_PIDS -DDEBUGGI
+NG -fno-strict-aliasing -I/usr/local/include -I/usr/include/gdbm'
    ccversion='', gccversion='3.2.3 20030502 (Red Hat Linux 3.2.3-19)'
+, gccosandvers=''
gccversion='3.2.3 200305'
    intsize=o, longsize=s, ptrsize=l, doublesize=8, byteorder=1234
    d_longlong=define, longlongsize=8, d_longdbl=define, longdblsize=1
+2
    ivtype='long'
k', ivsize=4'
ivtype, nvtype='double'
o_no', nvsize=, Off_t='', lseeksize=8
    alignbytes=4, prototype=define
  Linker and Libraries:
    ld='gcc'
l', ldflags =' -L/usr/local/lib'
ldflags_use'
    libpth=/usr/local/lib /lib /usr/lib
    libs=-lnsl -lgdbm -ldb -ldl -lm -lpthread -lc -lcrypt -lutil
    perllibs=
    libc=/lib/libc-2.3.2.so, so=so, useshrplib=true, libperl=libper
    gnulibc_version='2.3.2'
  Dynamic Linking:
    dlsrc=dl_dlopen.xs, dlext=so', d_dlsymun=undef, ccdlflags='-rdynam
+ic -Wl,-rpath,/usr/lib/perl5/5.8.0/i386-linux-thread-multi/CORE'
    cccdlflags='-fPIC'
ccdlflags='-rdynamic -Wl,-rpath,/usr/lib/perl5', lddlflags='s Unicode/
+Normalize XS/A'


Characteristics of this binary (from libperl):
  Compile-time options: DEBUGGING MULTIPLICITY USE_ITHREADS USE_LARGE_
+FILES PERL_IMPLICIT_CONTEXT
  Locally applied patches:
        MAINT18379
  Built under linux
  Compiled at Sep 15 2003 10:03:52
  @INC:
    /usr/lib/perl5/5.8.0/i386-linux-thread-multi
    /usr/lib/perl5/5.8.0
    /usr/lib/perl5/site_perl/5.8.0/i386-linux-thread-multi
    /usr/lib/perl5/site_perl/5.8.0
    /usr/lib/perl5/site_perl
    /usr/lib/perl5/vendor_perl/5.8.0/i386-linux-thread-multi
    /usr/lib/perl5/vendor_perl/5.8.0
    /usr/lib/perl5/vendor_perl
    /usr/lib/perl5/5.8.0/i386-linux-thread-multi
    /usr/lib/perl5/5.8.0
    .

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Replies are listed 'Best First'.
Re^3: undef quite slow?
by PodMaster (Abbot) on Aug 04, 2004 at 08:23 UTC
    And I am not entirely sure what you mean by "with or without perl's malloc" - could you elaborate a bit on the pros and cons of that?
    Perl is usually (by default?) compiled with your libc's malloc. Perl can also be compiled to use its own malloc ( perl -V:usemymalloc ). My suggestion is advice from perlfaq3, particularly from "How can I make my Perl program take less memory?". I really don't know much about it (never use it), but perl's malloc is supposed to be faster (or better suited for perl), but may present a challenge when compiling some eXStension (at least as-hinted-by http://inline.perl.org/java/faq.html). You can find more reading if you grep perl/lib/Pod/ for malloc
    I don't think I can upgrade the libc on this machine.... I've just tried it on a very differently configured machine (perl -V output for that one is below) and it doesn't seem to have the same problem, unfortunately the above configuration is what we use everywhere.
    You'll notice that that the "working" perl is compiled with libc=/lib/libc-2.3.2.so, while the one you use everywhere is compiled with libc=/lib/libc-2.2.5.so. You should be able to compile perl with a newer libc without replacing/upgrading your systems current libc.

    MJD says "you can't just make shit up and expect the computer to know what you mean, retardo!"
    I run a Win32 PPM repository for perl 5.6.x and 5.8.x -- I take requests (README).
    ** The third rule of perl club is a statement of fact: pod is sexy.

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Re^3: undef quite slow?
by ysth (Canon) on Aug 04, 2004 at 08:37 UTC
    gnulibc_version='2.2.5'
    IIRC, that's one of the versions with the buggy malloc that was rewritten for 2.3. Try configuring perl with -Dusemymalloc.
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