Re^10: Finding the size of a nested hash in a HoH

Replacing tasklist.exe with ps, your code worked with my machine and it shows while/each is faster and smaller.
1. About Speed
I noticed from your code, I was very unfair to while/each because I lack value assignment with foreach/keys test function. When I change Benchmark test function from

    foreach my $k (keys %h){
    }
[download]

    foreach my $k (keys %h){
        my $v=$h{$k};
    }
[download]

, benchmark shows while/each becomes faster

case 10000
hash ready ... count=10000
Sat Nov 12 01:13:29 2011
----------------------------------------
           Rate test_each test_keys
test_each 108/s        --      -28%
test_keys 151/s       40%        --
----------------------------------------
Sat Nov 12 01:14:22 2011

case 100000
hash ready ... count=100000
Sat Nov 12 01:14:23 2011
----------------------------------------
            Rate test_keys test_each
test_keys 4.63/s        --      -23%
test_each 6.02/s       30%        --
----------------------------------------
Sat Nov 12 01:15:20 2011

case 1000000
hash ready ... count=1000000
Sat Nov 12 01:15:32 2011
----------------------------------------
          s/iter test_keys test_each
test_keys   2.71        --      -30%
test_each   1.89       43%        --
----------------------------------------
Sat Nov 12 01:16:35 2011

case 2000000
hash ready ... count=2000000
Sat Nov 12 01:19:32 2011
----------------------------------------
          s/iter test_keys test_each
test_keys   5.69        --      -31%
test_each   3.91       46%        --
----------------------------------------
Sat Nov 12 01:21:49 2011
[download]

2. About memory
With ps command, while/each loop shows very very small memory usage. Memory allocation of "keys" is significant.

$./025-6.pl -M1=keys -M2=pairs -N=1e6
hash built, starting timer
Took 3.931463 and 39.000MB extra memory for 1000000 using keys/pairs m
+ethod
$./025-6.pl -M1=each -M2=pairs -N=1e6
hash built, starting timer
Took 2.434757 and 1.000MB extra memory for 1000000 using each/pairs me
+thod
[download]

It seems I miss something with GTop.

Comment on Re^10: Finding the size of a nested hash in a HoH Select or Download Code

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Re^11: Finding the size of a nested hash in a HoH by BrowserUk (Patriarch) on Nov 12, 2011 at 02:46 UTC
I noticed from your code, I was very unfair to while/each because I lack value assignment with foreach/keys test function. When I change Benchmark test function from `foreach my $k (keys %h){ }` [download] Look at the code again carefully. When the command line argument `-M2=pairs` the code run for the for / keys test is: `else { if( $M2 eq 'pairs' ) { for my $k ( keys %hash ) { my $v = $hash{ $k }; ++$count; } }` [download] Ie. This is equivalent to the while / each case for `-M2=pairs` of: `if( $M1 eq 'each' ) { if( $M2 eq 'pairs' ) { while( my( $k, $v ) = each %hash ) { ++$count; } }` [download] To perform the test for both cases where only the keys are accessed, use a command line argument of `-M2=keysonly` (or any value other than `pairs`). The code that gets run for two methods in this case are: `else { while( my $k = each %hash ) { ++$count; } }` [download] and `else { for my $k ( keys %hash ) { ++$count; } }` [download] Again, equivalent code. Thanks for confirming my premise. With the rise and rise of 'Social' network sites: 'Computers are making people easier to use everyday' 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] [d/l] [select]

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Re^11: Finding the size of a nested hash in a HoH
by BrowserUk (Patriarch) on Nov 12, 2011 at 02:46 UTC

I noticed from your code, I was very unfair to while/each because I lack value assignment with foreach/keys test function. When I change Benchmark test function from
foreach my $k (keys %h){ }
[download]

Look at the code again carefully. When the command line argument -M2=pairs the code run for the for / keys test is:

else {
    if( $M2 eq 'pairs' ) {
        for my $k ( keys %hash ) {
            my $v = $hash{ $k };
            ++$count;
        }
    }
[download]

Ie. This is equivalent to the while / each case for -M2=pairs of:

if( $M1 eq 'each' ) {
    if( $M2 eq 'pairs' ) {
        while( my( $k, $v ) = each %hash ) {
            ++$count;
        }
    }
[download]

To perform the test for both cases where only the keys are accessed, use a command line argument of -M2=keysonly (or any value other than pairs). The code that gets run for two methods in this case are:

    else {
        while( my $k = each %hash ) {
            ++$count;
        }
    }
[download]

and

    else {
        for my $k ( keys %hash ) {
            ++$count;
        }
    }
[download]

Again, equivalent code.

Thanks for confirming my premise.

With the rise and rise of 'Social' network sites: 'Computers are making people easier to use everyday'

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.

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[d/l]
[select]