<s>
Cost	B-Operating_System
efficiency	I-Operating_System
(	O
or	O
cost	B-Operating_System
optimality	I-Operating_System
)	O
,	O
in	O
the	O
context	O
of	O
parallel	B-Operating_System
computer	I-Operating_System
algorithms	O
,	O
refers	O
to	O
a	O
measure	O
of	O
how	O
effectively	O
parallel	B-Operating_System
computing	I-Operating_System
can	O
be	O
used	O
to	O
solve	O
a	O
particular	O
problem	O
.	O
</s>
<s>
A	O
parallel	O
algorithm	O
is	O
considered	O
cost	B-Operating_System
efficient	I-Operating_System
if	O
its	O
asymptotic	O
running	O
time	O
multiplied	O
by	O
the	O
number	O
of	O
processing	O
units	O
involved	O
in	O
the	O
computation	O
is	O
comparable	O
to	O
the	O
running	O
time	O
of	O
the	O
best	O
sequential	O
algorithm	O
.	O
</s>
<s>
For	O
example	O
,	O
an	O
algorithm	O
that	O
can	O
be	O
solved	O
in	O
time	O
using	O
the	O
best	O
known	O
sequential	O
algorithm	O
and	O
in	O
a	O
parallel	B-Operating_System
computer	I-Operating_System
with	O
processors	O
will	O
be	O
considered	O
cost	B-Operating_System
efficient	I-Operating_System
.	O
</s>
<s>
Cost	B-Operating_System
efficiency	I-Operating_System
also	O
has	O
applications	O
to	O
human	O
services	O
.	O
</s>
