control
unit
interfaces
required
without
a
corresponding
reduction
in
I/O
activity.
See
for
an
example
of
switched
point-to-point
topology.
MIF
Channel
Sharing
Topology:
MIF
further
improves
control
unit
connection
topologies
for
CPCs
with
multiple
LPs.
MIF
enables
many
LPs
to
share
a
physical
channel
path.
MIF
can
reduce
the
number
of
channels
and
control
unit
interfaces
required
without
a
corresponding
reduction
in
I/O
connectivity.
See
for
and
example
of
MIF
channel
sharing
topology.
MIF
Performance
Planning
Considerations
Your
installation
can
take
advantage
of
MIF
performance
enhancements
offered
by:
v
Understanding
and
utilizing
I/O-busy
management
enhancements
v
Planning
for
concurrent
data
transfer
v
Understanding
examples
of
MIF
consolidation
Understanding
and
Utilizing
I/O-Busy
Management
Enhancements:
This
section
shows
how
the
various
ESCON
or
FICON
and
MIF
topologies
offer
improvements
in
managing
I/O-busy
conditions.
compares
the
point-to-point,
switched
point-to
point,
and
MIF
channel
sharing
topologies.
Point-to-Point
Topologies:
Concentrate
I/O
attempts
at
the
control
unit
level
and
are
distance
dependent.
At
the
time
of
a
control
unit
busy
encounter,
the
control
unit
must
present
control
unit
busy
status
to
the
channel.
Once
the
control
unit
is
free,
it
presents
a
control
unit
no
longer
busy
status
to
the
channel.
This
process
of
presenting
status
to
the
channel
requires
control
unit
processing
and
many
trips
over
the
control
unit
to
channel
link.
Switched
Point-to-Point
Topologies:
Concentrate
I/O
attempts
within
the
Director
and
therefore
encounter
switch
port
busies.
The
processing
of
switch
port
busies
PR/SM LPAR Mode
Point-to-Point
Switched
Point-to-Point
MIF
Channel Sharing
MIF
Port
Busy
Condition
CU
Busy
Condition
CU
CU
CU
Channel
Busy
Condition
PR/SM LPAR Mode
PR/SM LPAR Mode
LP1
LP2
LP1
LP2
LP1
LP2
CH1
CH2
CH1
CH2
CH1
CH2
Figure
2-8.
Progression
of
Busy
Condition
Management
Improvements
2-22
PR/SM
Planning
Guide
Summary of Contents for Z9
Page 1: ...System z9 Processor Resource Systems Manager Planning Guide SB10 7041 03...
Page 2: ......
Page 3: ...System z9 Processor Resource Systems Manager Planning Guide SB10 7041 03...
Page 12: ...x PR SM Planning Guide...
Page 18: ...xvi PR SM Planning Guide...
Page 26: ...xxiv PR SM Planning Guide...
Page 54: ...1 28 PR SM Planning Guide...
Page 126: ...2 72 PR SM Planning Guide...
Page 220: ...4 8 PR SM Planning Guide...
Page 232: ...5 12 PR SM Planning Guide...
Page 250: ...B 16 PR SM Planning Guide...
Page 266: ...D 10 PR SM Planning Guide...
Page 272: ...X 6 PR SM Planning Guide...
Page 273: ......
Page 274: ...Printed in USA SB10 7041 03...
