<s>
The	O
staged	B-Architecture
event-driven	I-Architecture
architecture	I-Architecture
(	O
SEDA	O
)	O
refers	O
to	O
an	O
approach	O
to	O
software	B-Architecture
architecture	I-Architecture
that	O
decomposes	O
a	O
complex	O
,	O
event-driven	O
application	B-Application
into	O
a	O
set	O
of	O
stages	O
connected	O
by	O
queues	O
.	O
</s>
<s>
It	O
avoids	O
the	O
high	O
overhead	O
associated	O
with	O
thread-based	O
concurrency	B-Operating_System
models	O
(	O
i.e.	O
</s>
<s>
locking	O
,	O
unlocking	O
,	O
and	O
polling	O
for	O
locks	O
)	O
,	O
and	O
decouples	O
event	O
and	O
thread	B-Operating_System
scheduling	O
from	O
application	B-Application
logic	O
.	O
</s>
<s>
By	O
performing	O
admission	O
control	O
on	O
each	O
event	B-Operating_System
queue	I-Operating_System
,	O
the	O
service	O
can	O
be	O
well-conditioned	O
to	O
load	O
,	O
preventing	O
resources	O
from	O
being	O
overcommitted	O
when	O
demand	O
exceeds	O
service	O
capacity	O
.	O
</s>
