Accelerator Manual (G06.24+, H06.03+)

Accelerator Manual—527303-002
6-1
6 Accelerator Performance
Issues
Performance in Perspective
The Accelerator can greatly increase the performance of your programs. For most
programs, simply accelerating them with the Accelerator default options produces high-
performance code. You only need to read this section if you have a performance-
critical program that spends a significant percentage of processing time in user code.
Most application programs spend a substantial percentage of their execution time in
system code. HP system code has already been optimized for TNS/R systems.
You can use the Measure system performance-analysis tool to take multiple snapshots
of system use to determine which programs can be significantly affected by following
these performance-boosting strategies.
To increase the performance of accelerated programs, you can minimize:
•
Code generation by changing the setting of certain Accelerator options
•
The number of transitions into TNS code by:
°
Using ReturnValSize options to eliminate transitions
°
Recoding to eliminate transitions
•
The number of compatibility traps by recoding
Setting Accelerator options to account for specific variances in source programs results
in the most significant performance improvement. Reducing the number of transitions
into TNS code results in a less significant performance improvement, while reducing
the number of compatibility traps results in the least significant performance
improvement. Only attempt to reduce the number of transitions or compatibility traps in
performance-critical programs.
The performance-boosting strategies presented in this section often require significant
resources. Many of these changes require you to test your programs thoroughly to
make sure that the Accelerator produces a correctly executing program. Before
proceeding, check to see if you have already tried the following tasks to improve
performance.
•
Accelerate programs with the Inspect symbols region and the Binder region
present. To check if these regions are present:
°
In the Binder process enter:
SHOW SET SYMBOLS FROM object-file
°
In the Inspect symbolic debugger enter:
INFO OBJECT object-file