To clarifie, the caller gets the contect of the CURRENT subroutine call, hence

#!/usr/bin/perl -w

use strict;
sub jojo {
        my ($package, $filename, $line, $subroutine, $hasargs, $wantar
+ray, $evaltext, $is_require) = caller(1);
        print "2: " . $subroutine . "\n";
}

sub jo {
        my ($package, $filename, $line, $subroutine, $hasargs, $wantar
+ray, $evaltext, $is_require) = caller(1);
        print "1: " . $subroutine . "\n";
        jojo;
}

jo;
[download]

would print:
Use of uninitialized value in concatenation (.) or string at ./test.pl line 11.
1:
2: main::jo
As you see, the first call doesn't show a caller, since there is no sub that clalled it, only the package would be known, and you should give the depth of info, thus the following should work

#!/usr/bin/perl -w

use strict;
sub jojo {
        my ($package, $filename, $line, $subroutine, $hasargs, $wantar
+ray, $evaltext, $is_require) = caller(1);
        print "2: $package - $subroutine \n";
}

sub jo {
        my ($package, $filename, $line, $subroutine, $hasargs, $wantar
+ray, $evaltext, $is_require) = caller();
        print "1: $package - $subroutine \n";
        jojo;
}

jo;
[download]

That prints:
1: main -
2: main - main::jo