Bottleneck At Heaven's Gates (Part Eight)

Bottleneck At Heaven's Gates (Part Eight)



eT rick
is to q
uan tify the
ad van
tag e o f a pro
pos ed
enh anc em ent
F00 30
CS /EE
58 10
CS /EE
68 10
Am dah l's L
aw
Qu ant ific atio
n o f th e d imi nis hin g re
tur n p
rin cip
le
eD efin es spe
edu p g ain ed fro m a
pa rtic ula r fe atu re
eN ote XE Q-t ime
is 1/p erf orm
anc e
eD epe nds on 2 f act ors
kF rac tion
of ori gin
al c
om put atio
n ti me tha
t ca n ta k a dva
nta ge of
the en han
cem
ent
kL eve l of im pro
vem
ent of the en han
cem
ent
Exe cut ion tim
e w itho
ut u sin g th
e e nha
nce me nt
Exe cut ion tim
e u sin g th
e e nha
nce me nt
Sp eed
up =
Pag e 6
F00 31
CS /EE
58 10
CS /EE
68 10
Am dah l's L
aw
ExT ime
new = E
xTi me
old x
(1 - F rac tion
enh anc ed)
+ F
rac tion
enh anc ed
Sp eed
up
ove rall =
ExT ime
old
ExT ime
new
Sp eed
up
enh anc ed
= 1
(1 - Fr act
ion
enh anc ed)
+ F
rac tion
enh anc ed
Sp eed
up
enh anc ed
F00 32
CS /EE
58 10
CS /EE
68 10
Sim ple Exa mpl e
Be wa re,
Am dah
l's law
sa ys not
hin g a bou
t co st
eF or one
ap plic
atio n:
kF P in
str uct
ion s a cco
unt for 50 % o
f in stru
ctio ns
kF PS QR
T is
20 %
kO the r 30
%
eD esi gne
rs s ay the se are
po ssi ble (at the
sa me
cos t)
kI mp
rov e F PS QR
T b y 4 0x
ki mp
rov e a ll F P b y 2 x
kI mp
rov e o the r (n on sqr t) F P b y 8 x
eW hic h o ne sho
uld yo u d o?
F00 33
CS /EE
58 10
CS /EE
68 10
And the ans
wer is…
eF PS QR T
eF P
eO
TH ER
1
(1-0 .2) +
0.2 40
= 1 .24 2
=
1
(1-0 .5) +
0.5 2
= 1 .33 3
=
1
(1-0 .3) +
0.3 8
= 1 .35 6
=
F00 34
CS /EE
58 10
CS /EE
68 10
Ano ther Am dah l's E
xam ple
eS upp
ose ap plic
atio n is "a lmo
st a ll" par
alle l: 9 0%
kW hat is the sp eed
up usi ng 10, 10 0, a
nd 100
0 p roc ess ors ?
# o f pr
oce sso rs = P
Fra ctio
n
enh
anc ed =
0.9
Sp eed
up
p =
1
0.9 P
0.1 +
Sp eed
up
10 =
1 0.
9 10
0.1 +
1 0.19
=
= 5 .3
Sp eed
up
100 =
1 0.9 100
0.1 +
1 0.10



august highland

muse apprentice guild
–"expanding the canon into the 21st century"
www.muse-apprentice-guild.com

culture animal
–"following in the footsteps of tradition"
www.cultureanimal.com














—
Outgoing mail is certified Virus Free.
Checked by AVG anti-virus system (http://www.grisoft.com).
Version: 6.0.512 / Virus Database: 309 - Release Date: 8/19/2003