use Devel::Size qw[ total_size ];
...

printf "%s :: %.f\n", $_, total_size( $::{ $_ } ) for keys %::;;

##</code><code>##

/ :: 382
stderr :: 289
SIG :: 3705
, :: 399
utf8:: :: 4359
" :: 347
_<c:/Perl/site/lib/auto/Devel/Size/Size.dll :: 479
DynaLoader:: :: 55772
Devel:: :: 22977
strict:: :: 6435
stdout :: 289
AllocMemory :: 2263
&#8597; :: 262
| :: 383
_<c:/Perl/lib/auto/Time/HiRes/HiRes.dll :: 463
Mac:: :: 1706
CleanString :: 15703
Regexp:: :: 948
_code :: 443
UNIVERSAL:: :: 1872
overload:: :: 39770
$ :: 287
time :: 829
NewString :: 13443
size :: 820
Data:: :: 111665
- :: 679
_<..\universal.c :: 363
_<HiRes.c :: 343
BEGIN :: 287
! :: 380
IO:: :: 943
&#9788; :: 399
total_size :: 844
&#8593; :: 345
pp :: 12454
_ :: 345
_<c:/Perl/site/lib/auto/Win32/API/API.dll :: 471
+ :: 679
Exporter:: :: 81873
Internals:: :: 3436
STDIN :: 287
Config:: :: 91676
warnings:: :: 59111
DB:: :: 850
Time:: :: 33192
_<.\win32.c :: 343
&#9644; :: 345
_<perllib.c :: 343
2 :: 388
_<API.c :: 335
cmpthese :: 27607
1 :: 406
&#8616;ARNING_BITS :: 400
CORE:: :: 930
_<Size.c :: 339
attributes:: :: 962
stdin :: 287
ARGV :: 405
INC :: 2857
Scalar:: :: 1789
ENV :: 6689
? :: 395
vars:: :: 9565
subs:: :: 3764
_<..\perlio.c :: 351
main:: :: 720485
AutoLoader:: :: 24976
Carp:: :: 31355
VMS:: :: 1229
Win32:: :: 256452
PerlIO:: :: 2378
0 :: 431
 :: 562
_<..\xsutils.c :: 355
@ :: 950
ApiLink :: 10523
Benchmark:: :: 131181
STDOUT :: 289
] :: 355
3 :: 386
&#8616; :: 383
MIME:: :: 1215
STDERR :: 289
_<dl_win32.c :: 330
<none>:: :: 460
sleep :: 839

##</code><code>##

[0] Perl> printf "%s :: %.f\n", $_, total_size( $::{ $_ } ) for keys %{ Benchmark:: };;
timesum :: 112
__ANON__ :: 112
cpu_a :: 112
a :: 112
n_to_for :: 112
_doeval :: 112
iters :: 112
_Usage :: 112
Min_CPU :: 112
init :: 112
cmpthese :: 27607
debug :: 112
export :: 112
new :: 112
timestr :: 112
EXPORT_TAGS :: 112
timethis :: 112
countit :: 112
EXPORT_OK :: 112
confess :: 112
EXPORT_FAIL :: 112
timediff :: 112
cpu_c :: 112
b :: 112
ISA :: 112
export_to_level :: 112
Default_Style :: 112
timethese :: 112
time :: 829
Cache :: 112
cpu_p :: 112
Debug :: 112
clearcache :: 112
BEGIN :: 287
Do_Cache :: 112
runloop :: 112
timedebug :: 112
real :: 112
usage :: 112
clearallcache :: 112
timeit :: 112
EXPORT :: 112
croak :: 112
import :: 112
disablecache :: 112
enablecache :: 112
Min_Count :: 112
carp :: 112
Default_Format :: 112
VERSION :: 112
mytime :: 112