Greetings,
To decrease the number of trips to and from the shared-manager, one can provide a suffix (k * 1024) or (m * 1024 * 1024) for the 3rd argument to read. That there enables chunk IO. Not to worry, the shared-manager completes reading until reaching the end of line or record. Notice $. It is the chunk_id, not the actual line number. The chunk_id value is important when output order is desired.
OP's script involving semaphore + yield: 3.6 seconds. Shared handle (non-chunking): 1.1 seconds.
Below, chunking completes in 0.240 seconds which is the total running time including initial gzip.
use strict;
use threads;
use MCE::Shared;
{
open my $fh, '|-', 'gzip > test.txt.gz';
foreach (1..100000) {
print {$fh} sprintf('%04d',$_).('abc123' x 10)."\n";
}
close $fh;
}
{
mce_open my $fh, '-|', 'gzip -cd test.txt.gz' or die "open error:
+$!\n";
mce_open my $out, '>', \*STDOUT or die "open error: $!\n";
my @thrs;
foreach (1..3) {
push @thrs, threads->create('test');
}
$_->join() foreach @thrs;
close($fh);
sub test {
my $tid = threads->tid();
# using shared output to not garble among threads
while (1) {
my $n_chars = read $fh, my($buf), '4k';
last if (!defined $n_chars || $n_chars <= 0);
print {$out} "## thread: $tid, chunkid: $.\n".$buf;
}
}
}
Regards, Mario.
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