Hitachi Compute Blade 2000 User Manual page 1067

LPAR manager modifies the allocation rate from the shared LPAR definition when it
meets the following condition:
If the allocation rate for the calculation per logical processor is less than 1 %,

the service rate is compensated so that the time in which a single logical
processor uses the physical processor becomes 1% (10 milliseconds) of the
unit processor time (1 second).
If the number of logical processors allocated to a single LPAR does not satisfy

the assigned allocation rate, the allocation rate is compensated to the one that
is based on the number of logical processors.
(3) Idle detection
A shared mode LPAR, which is enabling its idle detection and not using much CPU
compared to the allocated rate, can give its processor time to another shared mode
LPAR requiring it. The busy shared mode LPAR that takes over the processor time
can use more processor-time than the allocation rate. As a result, the system can
use CPUs time more efficiently.
Although this function does not work to a dedicated mode LPAR, make sure to set
the default value: Y for correct performance.
All- shar ed pro cessor servi ce
Actual s er vic e t o LPAR 1 Actual
s er vic e
t o
LPA R2
LPA R2
wor kload
decr eas es .
LPA R2
wor kload
incr eas es .
(4) Processor capping
With the processor capping function on, the shared mode LPAR does not take on
the unused (idle) capacity of other LPARs even if the LPAR requires more
performance than its allocation rate (busy status). Therefore, the LPAR's
processor-time never uses more processor-time than the allocation rate, even if it is
busy. However, because the LPAR manager allocation rate control allows a
tolerance of 1% for each unit of processor-time, a shared mode LPAR is allocated a
maximum processor-time that is 1% greater than the total service time of the
physical processors assigned to it, and might exceed the allocation rate.
The processor capping can be available only for LPARs in shared mode and not for
LPARs in dedicated mode, to which the service ratio cannot be specified.
All- shar ed pro cessor servi ce
Actual s er vic e Actual s er vic e
t o LPAR 1 t o LPAR 2
LPA R1
wor kload
decr eas es .
LPA R1
wor kload
incr eas es .
1016
All- shar ed pro cessor servi ce
Actual Actual s er vic e t o LPAR 2
s er vic e
t o
LPA R1