Re^4: Avoid Locking Entire Hashes

Neither it seems is ikegami's original suggestion:

#! perl -slw
use strict;
use Data::Dump qw[ pp ];
use Time::HiRes qw[ time ];
use List::Util qw[ shuffle ];
use threads;
use threads::shared;

our $START //= 'aaa';
our $END   //= 'zzz';

my %sems :shared = map{ my $n :shared = 0; $_ => \$n } $START .. $END;
my %hash :shared = map{ $_ => 0 } $START .. $END;

my $start = time;
$_->join for map{
    async{
        my @order = shuffle keys %hash;
        for ( @order ) {
            lock ${ $sems{ $_ } };
            ++$hash{ $_ };
        }
    }
} 1 .. 4;

printf "Lock scalar ref took %.3f seconds\n", time() - $start;

my @fails = grep $_ != 4, values %hash;

warn @fails . " fails\n" if @fails;

__END__
C:\test>909437-3
Lock scalar ref took 2.937 seconds
2840 fails
[download]

Examine what is said, not who speaks -- Silence betokens consent -- Love the truth but pardon error.

"Science is about questioning the status quo. Questioning authority".

In the absence of evidence, opinion is indistinguishable from prejudice.

Comment on Re^4: Avoid Locking Entire Hashes Download Code

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Re^5: Avoid Locking Entire Hashes by ikegami (Patriarch) on Jun 15, 2011 at 04:26 UTC
Neither it seems is ikegami's original suggestion: We knew that two days ago, so we fixed it two days ago.	[reply]
Re^6: Avoid Locking Entire Hashes by BrowserUk (Patriarch) on Jun 15, 2011 at 04:29 UTC
The modified version is broken also. As demonstrated by the attached code. Examine what is said, not who speaks -- Silence betokens consent -- Love the truth but pardon error. "Science is about questioning the status quo. Questioning authority". In the absence of evidence, opinion is indistinguishable from prejudice.	[reply]
Re^7: Avoid Locking Entire Hashes by ikegami (Patriarch) on Jun 15, 2011 at 04:45 UTC
The number of elements in @order in each thread is "weird". For example, 6028, 11159, 22541 and 36060. It should be 17576, 17576, 17576 and 17576. `my @order = shuffle keys %hash;` [download] should be `my @order; { lock %hash; @order = shuffle keys %hash; }` [download] It's the test harness that's not thread-safe.	[reply] [d/l] [select]
Re^8: Avoid Locking Entire Hashes by BrowserUk (Patriarch) on Jun 15, 2011 at 04:57 UTC
Re^9: Avoid Locking Entire Hashes by ikegami (Patriarch) on Jun 15, 2011 at 05:14 UTC
Some notes below your chosen depth have not been shown here
Re^7: Avoid Locking Entire Hashes by ikegami (Patriarch) on Jun 15, 2011 at 04:33 UTC
You seem to have forgotten to attach the code? Update: ah, while it doesn't use my code, it does seem to indicate there's a race condition in my code.	[reply]