I have the following code intended to sort a hash of hashes by value:

#!/usr/bin/perl -w
use strict;

my %hoh_test;


$hoh_test{foo1}{bar} = -0.12697;
$hoh_test{foo1}{baz} = -0.000398154;
$hoh_test{foo2}{bar} = -4.0183e-05;
$hoh_test{foo2}{baz} = 0;
$hoh_test{foo3}{bar} = 9.966003977e-06;
$hoh_test{foo3}{baz} = 0.0001939;

# sort descending by value
foreach my $foo (keys(%hoh_test))
{
    foreach my $ba (sort {$hoh_test{$foo}{$b} <=> $hoh_test{$foo}{$a}}
+ keys(%{$hoh_test{$foo}}))
    {
        printf("foo: $foo, ba: $ba, value: %s\n", $hoh_test{$foo}{$ba}
+);
    }
}
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Here is the expected output:

foo: foo3, ba: baz, value: 0.0001939
foo: foo3, ba: bar, value: 9.966003977e-06
foo: foo2, ba: baz, value: 0
foo: foo2, ba: bar, value: -4.0183e-05
foo: foo1, ba: baz, value: -0.000398154
foo: foo1, ba: bar, value: -0.12697
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The actual output varies most times the program is run, so clearly my code doesn't work as intended. My two questions are:

1. How can I fix this to sort by values?
2. What exactly is it even doing now? Given that the output changes with most runs it doesn't appear to be sorting by anything.