pearl question: multiple threads of ECM

[Andi47]

I am attempting to code a pearl script which launches multiple threads of ECM.exe: (configured to use 7 threads of my i7 here, as the 8th thread is busy with an msieve poly select)

use Math::BigInt;
use Math::BigFloat;

$NUM_CPUS=7;
$NUM_THREADS=$NUM_CPUS;

$ECHO_CMDLINE=1;

### ECM parameters ###

$B1=43000000;
$NUM_CURVES=777; #total number of curves 
$MAXMEM=900; #max. memory used per thread

$INPUTFILE="alq10212.2315.txt";
$ECM_OUTPUTNAME="alq10212.2315_43e6.out";


############# nothing configurable below here! #######################

$CNUM=int($NUM_CURVES)/$NUM_THREADS; #note: this will cause rounding errors if $NUM_CURVES is not divisible by $NUM_THREADS

if ($NUM_THREADS != 1) {
  use Config; 
  if (!($Config{usethreads})) { 
    printf "This version of Perl doesn't support multiple threads.  Only using 1 thread.";
    $NUM_THREADS=1; 
  }
  else {
    use Thread qw(async);
  }
}

# statements below copied from factmsieve.pl and modified for running ecm

  if ($NUM_THREADS==1) {
    # It's very important to call like this, so that if the user CTRL-C's,
    # or otherwise kills the process, we see it and terminate as well.
    unlink($ECM_OUTPUTNAME);
    $cmd="ecm -nn -maxmem $MAXMEM -c $CNUM <$INPUTFILE $B1 >>$ECM_OUTPUTNAME";
    print "=>$cmd\n" if($ECHO_CMDLINE);
    $res=system($cmd);
  }
  else {
    @thd = (1 .. $NUM_THREADS);
    for ($j=1;$j<=$NUM_THREADS;$j++) {
      unlink("$ECM_OUTPUTNAME.T$j");
      $cmd="ECM -nn -maxmem $MAXMEM -c $CNUM <$INPUTFILE $B1 >>$ECM_OUTPUTNAME.T$j";
      print "=>$cmd\n" if($ECHO_CMDLINE);
      $thd[$j]=async{system($cmd)};
    }
#    $res=0;
#    for ($j=1;$j<=$NUM_THREADS;$j++) {
#      $res+=eval{$thd[$j]->join()};
#    }
#    for ($j=1;$j<=$NUM_THREADS;$j++) {
#      if ($LATSIEVE_SIDE) {
#        unlink <$JOBNAME.T$j.afb.1> if ($sieverRL == ($Q0-1));
#      }
#      else {
#        unlink <$JOBNAME.T$j.afb.0> if ($sieverAL == ($Q0-1));
#      }
#      $cmd="\"$CAT\" $SIEVER_OUTPUTNAME.T$j >> $SIEVER_OUTPUTNAME";
#      print "=>$cmd\n" if($ECHO_CMDLINE);
#      concat("$SIEVER_OUTPUTNAME.T$j", ">>", "$SIEVER_OUTPUTNAME");
#      unlink "$SIEVER_OUTPUTNAME.T$j";
#    }
  }

When I run this script (command line window under Win 7 professional, 64 bit), I get this screen output:

=>ECM -nn -maxmem 900 -c 111 <alq10212.2315.txt 43000000 >>alq10212.2315_43e6.out.T1
=>ECM -nn -maxmem 900 -c 111 <alq10212.2315.txt 43000000 >>alq10212.2315_43e6.out.T2
=>ECM -nn -maxmem 900 -c 111 <alq10212.2315.txt 43000000 >>alq10212.2315_43e6.out.T3
=>ECM -nn -maxmem 900 -c 111 <alq10212.2315.txt 43000000 >>alq10212.2315_43e6.out.T4
=>ECM -nn -maxmem 900 -c 111 <alq10212.2315.txt 43000000 >>alq10212.2315_43e6.out.T5
=>ECM -nn -maxmem 900 -c 111 <alq10212.2315.txt 43000000 >>alq10212.2315_43e6.out.T6
=>ECM -nn -maxmem 900 -c 111 <alq10212.2315.txt 43000000 >>alq10212.2315_43e6.out.T7
Perl exited with active threads:
        7 running and unjoined
        0 finished and unjoined
        0 running and detached

According to the output files which have appeared in my ecm directory, only threads T1, T2, T3, T4 and T6 have been spawned, but not T5 and T7. Any ideas why?

[Andi47]

Originally Posted by Andi47

According to the output files which have appeared in my ecm directory, only threads T1, T2, T3, T4 and T6 have been spawned, but not T5 and T7. Any ideas why?

Hmmm... I think I found out why the threads have been left unjoined and two of them had died immediately: I accidently commented out these lines:

    $res=0;
    for ($j=1;$j<=$NUM_THREADS;$j++) {
      $res+=eval{$thd[$j]->join()};
    }

[Andi47]

Current version (with the line mentioned in post #2 NOT commented out):

use Math::BigInt;
use Math::BigFloat;
# Bah, this causes a fatal error if GMP BigInt is not available.
# use Math::BigInt lib => 'GMP';

$NUM_CPUS=7;
$NUM_THREADS=$NUM_CPUS;

$ECHO_CMDLINE=1;

### ECM parameters ###

$B1=26e7;
$NUM_CURVES=91; #total number of curves 
$MAXMEM=900; #max. memory used per thread

#$INPUTFILE="alq10212.2351.txt";
#$ECM_OUTPUTNAME="alq10212.2351_3e6.out";

$INPUTFILE="alq4788.2549.txt";
$ECM_OUTPUTNAME="alq4788.2549_h_26e7.out";



############# nothing configurable below here! #######################

$CNUM=int($NUM_CURVES)/$NUM_THREADS; #note: this will cause rounding errors if $NUM_CURVES is not divisible by $NUM_THREADS

if ($NUM_THREADS != 1) {
  use Config; 
  if (!($Config{usethreads})) { 
    printf "This version of Perl doesn't support multiple threads.  Only using 1 thread.";
    $NUM_THREADS=1; 
  }
  else {
    use Thread qw(async);
  }
}


  if ($NUM_THREADS==1) {
    # It's very important to call like this, so that if the user CTRL-C's,
    # or otherwise kills the process, we see it and terminate as well.
    unlink($ECM_OUTPUTNAME);
    $cmd="ecm -nn -maxmem $MAXMEM -c $CNUM <$INPUTFILE $B1 >>$ECM_OUTPUTNAME";
    print "=>$cmd\n" if($ECHO_CMDLINE);
    $res=system($cmd);
  }
  else {
    @thd = (1 .. $NUM_THREADS);
    for ($j=1;$j<=$NUM_THREADS;$j++) {
      unlink("$ECM_OUTPUTNAME.T$j");
      $cmd="ECM -nn -maxmem $MAXMEM -c $CNUM <$INPUTFILE $B1 >>$ECM_OUTPUTNAME.T$j";
      print "=>$cmd\n" if($ECHO_CMDLINE);
      $thd[$j]=async{system($cmd)};
    }
    $res=0;
    for ($j=1;$j<=$NUM_THREADS;$j++) {
      $res+=eval{$thd[$j]->join()};
    }
  }