Object Code Accelerator Manual

Introduction
Object Code Accelerator Manual—528144-003
1-4
OCA Resource Requirements
Figure 1-4, Comparing TNS and Accelerated Object File Sizes Without a Symbols
Region, on page 1-4 shows that an accelerated object file, with a symbols region,
requires about 25 percent more disk storage space than the corresponding TNS object
file. You can strip the symbols region from the accelerated program without affecting
performance. However, accelerate the TNS object file with the symbols region and
then strip the symbols region. OCA produces more efficient code from source TNS
object files that contain a symbols region than those without the region.
The inline code expansion factor measures the worst-case increase in main memory
required for accelerated code; the typical increase is less. It is the number of bytes of
Itanium code divided by the number of bytes of TNS code. Itanium instructions are 32
bits and TNS instructions are 16 bits; thus, a one-to-one instruction matching produces
an inline expansion factor of 2. The OCA listing reports the inline code expansion
factor.
The typical inline expansion factor in executable Itanium code compared to TNS code
is 2 to 4 times. In one typical OLTP application, the code pages working set for the HP-
supplied system code increased approximately 190 percent on a TNS/E as compared
to a TNS system.
Figure 1-4. Comparing TNS and Accelerated Object File Sizes Without a
Symbols Region
TNS Object Code
Binder Region
Symbols Region
Accelerated
Object Code
VST0103.vdd