Page 138 - slides.dvi

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•
•
•
•
Unix
so
Case
Unix
and
over
if
gives
load j
Round
is
Study—
the
e.g.
the
Priorities
Priorities
nice j
“forgotten”
the
is
robin
last
are
Process
load
a
Process
is
0–127;
priority
1
within
based
within
of
Scheduling
CP
minute
5
sampled
⇒
user
on
of
P j (i)
(partially)
U j (i)
=
process
=
usage
average
j
priorities,
Scheduling
seconds.
user
(2
processes
at
2
operation
and
×
≥
Base j
×
approximately
length
the
+
nice
of
quantum
load j )
CP
90%
PUSER
load j
controllable
the
+
=
of
value,
4
U j (i
1
beginning
run
100ms.
50.
−
1 CP
i.e.
of
1)
U j (i
+
queue
adjustment
seconds
2
−
in
×
interval
1)
i
CPU
+
which
nice j
parameter
nice j
usage
where:
∈
will
process
j
[−20,
be
20].
resides,
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