Re: PerlIO file handle dup

Hi chris212,

At the time of my last reply, I didn't realize you had made an update. Disclaimer: Oh, btw, I'm not here to push MCE. Please use the module of your liking. Depending on the OS and/or number of workers, MCE::Mutex may run faster than Thread::Semaphore.

Thread::Semaphore

use strict; use warnings;

use threads;
use Thread::Semaphore;
use MCE::Shared;
use Time::HiRes 'time';

my $condvar = MCE::Shared->condvar;
my $sem     = Thread::Semaphore->new;

# Start the shared server. Not necessary if Perl has IO::FDPass.
MCE::Shared->start;

sub test {
    $condvar->wait;
    for (1..10000) {
        threads->yield;
        $sem->down;
        $sem->up;
    }
}

threads->create('test') for 1..3;
$condvar->broadcast(0.5);

my $start = time;
$_->join for threads->list;

printf "duration: %0.03f secs\n", time - $start;
[download]

MCE::Mutex::Channel

use strict; use warnings;

use threads;
use MCE::Mutex;
use MCE::Shared;
use Time::HiRes 'time';

my $condvar = MCE::Shared->condvar;
my $mutex   = MCE::Mutex->new;

# Start the shared server. Not necessary if Perl has IO::FDPass.
MCE::Shared->start;

sub test {
    $condvar->wait;
    for (1..10000) {
        threads->yield;
        $mutex->lock;
        $mutex->unlock;
    }
}

threads->create('test') for 1..3;
$condvar->broadcast(0.5);

my $start = time;
$_->join for threads->list;

printf "duration: %0.03f secs\n", time - $start;
[download]

MCE::Mutex::Flock

use strict; use warnings;

use threads;
use MCE::Mutex;
use MCE::Shared;
use Time::HiRes 'time';

my $condvar = MCE::Shared->condvar;
my $mutex   = MCE::Mutex->new( impl => 'Flock' );

# Start the shared server. Not necessary if Perl has IO::FDPass.
MCE::Shared->start;

sub test {
    $condvar->wait;
    for (1..10000) {
        threads->yield;
        $mutex->lock;
        $mutex->unlock;
    }
}

threads->create('test') for 1..3;
$condvar->broadcast(0.5);

my $start = time;
$_->join for threads->list;

printf "duration: %0.03f secs\n", time - $start;
[download]

Results

My laptop is a late 2013 Macbook Pro, 2.6 Ghz i7 quad CPU. Each virtual machine is configured with 4 cores.

* 3 threads: CentOS Linux 7.3

    Thread::Semaphore     0.386 secs
    MCE::Mutex::Channel   0.162 secs
    MCE::Mutex::Flock     0.144 secs
[download]

* 3 threads: Windows 7

    Thread::Semaphore     0.293 secs
    MCE::Mutex::Channel   0.499 secs
    MCE::Mutex::Flock     0.498 secs
[download]

* 20 threads: CentOS Linux 7.3

    Thread::Semaphore    41.897 secs
    MCE::Mutex::Channel   0.980 secs
    MCE::Mutex::Flock     0.702 secs
[download]

* 20 threads: Windows 7

    Thread::Semaphore    35.521 secs
    MCE::Mutex::Channel   2.994 secs
    MCE::Mutex::Flock     3.322 secs
[download]

Regards, Mario

Comment on Re: PerlIO file handle dup Select or Download Code

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Re^2: PerlIO file handle dup
by marioroy (Prior) on Sep 03, 2018 at 01:17 UTC

Using the OP's example, I modified it to do locking via MCE::Mutex. Afterwards, toyed with a couple MCE demonstrations. All demonstrations output orderly.

OP's example, locking via MCE::Mutex

#!/opt/perl/bin/perl
use strict;
use threads;
use MCE::Mutex;
use MCE::Shared;

open my $fh, '|-', 'gzip > test.txt.gz';
foreach (1..10000) {
    print {$fh} sprintf("%05d%s\n", $_, ('abc123' x 10));
}
close $fh;

mce_open $fh,'-|','gzip -cd test.txt.gz'
    or die "Failed to uncompress: $!\n";

$| = 1;

my @threads = ();
my $mutex = MCE::Mutex->new();

foreach (1..3) {
    push @threads, threads->create(\&test);
}

$_->join() foreach @threads;
close $fh;
print "\n";

sub test {
    my $tid = threads->tid();
    my $line;
    while(1) {
        threads->yield();
        $mutex->lock();
        $line = <$fh> or last;
        print "Thread $tid ".$line;
        $mutex->unlock();
    }
    $mutex->unlock;
}
[download]

MCE, no chunking

#!/opt/perl/bin/perl
use strict;
use threads;
use MCE;

open my $fh, '|-', 'gzip > test.txt.gz';
foreach (1..10000) {
    print {$fh} sprintf("%05d%s\n", $_, ('abc123' x 10));
}
close $fh;

open $fh, '-|', 'gzip -cd test.txt.gz'
    or die "Failed to uncompress: $!\n";

$| = 1;

# MCE spawns threads when threads is present

MCE->new(
    chunk_size => 1, max_workers => 3,
    input_data => $fh,
    init_relay => 1,
    user_func  => sub {
        my ($mce, $chunk_ref, $chunk_id) = @_;
        my $tid = threads->tid();
        MCE::relay sub {
            print "Thread $tid ".$chunk_ref->[0];
        };
    }
)->run;

close $fh;
print "\n";
[download]

MCE, chunking enabled

#!/opt/perl/bin/perl
use strict;
use threads;
use MCE;

open my $fh, '|-', 'gzip > test.txt.gz';
foreach (1..10000) {
    print {$fh} sprintf("%05d%s\n", $_, ('abc123' x 10));
}
close $fh;

open $fh, '-|', 'gzip -cd test.txt.gz'
    or die "Failed to uncompress: $!\n";

$| = 1;

# MCE spawns threads when threads is present

MCE->new(
    chunk_size => 500, max_workers => 3,
    input_data => $fh,
    init_relay => 1,
    user_func  => sub {
        my ($mce, $chunk_ref, $chunk_id) = @_;
        my $tid = threads->tid();
        my $buf = '';
        foreach my $line ( @{ $chunk_ref } ) {
            $buf .= "Thread $tid ".$line;
        }
        MCE::relay sub {
            print $buf;
        };
    }
)->run;

close $fh;
print "\n";
[download]

Results taken from a Linux CentOS 7.3 VM

My laptop is a late 2013 Macbook Pro, 2.6 Ghz i7 quad CPU. The Linux virtual machine is configured with 4 cores.

* 3 workers

  time perl script_sem.pl   | wc -l     # 0.543s OP's example
  time perl script_mutex.pl | wc -l     # 0.663s Ditto, MCE::Mutex
  time perl script_mce.pl   | wc -l     # 0.225s MCE, no chunking
  time perl script_chunk.pl | wc -l     # 0.077s MCE, chunking enabled
[download]

* 10 workers

  time perl script_sem.pl   | wc -l     # 1.072s OP's example
  time perl script_mutex.pl | wc -l     # 0.726s Ditto, MCE::Mutex
  time perl script_mce.pl   | wc -l     # 0.255s MCE, no chunking
  time perl script_chunk.pl | wc -l     # 0.112s MCE, chunking enabled
[download]

* 20 workers

  time perl script_sem.pl   | wc -l     # 1.849s OP's example
  time perl script_mutex.pl | wc -l     # 0.803s Ditto, MCE::Mutex
  time perl script_mce.pl   | wc -l     # 0.339s MCE, no chunking
  time perl script_chunk.pl | wc -l     # 0.179s MCE, chunking enabled
[download]

Regards, Mario

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