HP-UX Reference (11i v2 04/09) - 5 Miscellaneous Topics (vol 9)

a
Aries(5) Aries(5)
(Itanium(R)-based System Only)
In order to turn ON the beta translator, specify the Aries
-fast_trans option in Aries resource
configuration file. See the section ARIES RESOURCE CONFIGURATION FILE: PASSING OPTIONS
TO ARIES for more information.
Warning
Due to the beta nature of this translator, be aware that an element of risk is involved in deploying the
beta translator for mission-critical applications. This is not recommended. However, users are
encouraged to try the new beta translator and provide feedback on reliability and performance, so that it
soon attains the reliability of the existing standard dynamic translator in Aries.
Performance
Based on the measurements performed preparing this release, the beta translator has been found, on an
average, to be 20% faster than the existing standard translator, with regards to the translation time.
However, how this improvement in translation time reflects in the emulated application´s overall perfor-
mance is a variable factor. It has been observed in the lab that an overall performance gain of 20% on an
average can be expected in an applications that contain an average mix of compute intensive and user
intensive actions. More precise performance measurement of the beta translator is being carried out.
At the time of this release, the performance of compute intensive applications is found to be much slower
under the beta translator compared to the standard translator. If the performance of the beta translator
remains below par with the standard translator, the beta translator may be removed in a future release.
ARIES MEMORY MANAGEMENT
Aries Managed Area (AMA)
Aries consumes a small amount of memory toward the end of a PA-RISC application’s private data seg-
ment. This area is called Aries Managed Area (AMA). When an Itanium-based HP-UX operating system
launches Aries to emulate PA-RISC application, it reserves AMA exclusively for Aries use. The size of the
AMA is decided by following kernel tunable parameters:
•
pa_maxssiz_32bit
for 32-bit Aries
•
pa_maxssiz_64bit
for 64-bit Aries
See pa_maxssiz (5) for more details.
The Itanium-based HP-UX operating system passes a pointer
load_info to a structure of type
load_info_t defined in /usr/include/crt0.h
, to Aries. The start of AMA is marked by
load_info->li_priv_mmf_start
and the end of AMA is marked by load_info-
>li_bstore_start. Aries uses AMA to store following data:
1. Aries’s initialized data, uninitialized data (BSS) and thread local storage (TLS)
2. Aries heap for
malloc() calls used by Aries code and for creating Aries threads for emulation of
PA-RISC application’s threads
3. PA-RISC application’s stack
4. Translation code buffer (code cache region)
5. Aries’s private data structures
6. Memory area used by Aries dynamic translator as heap
The whole of AMA space is not allocated at once. Aries allocates memory from AMA dynamically. Due to
AMA, a PA-RISC application running under Aries will have larger memory footprint (also called resident
memory) compared to PA-RISC native system. The increase in resident memory size is not equal to the
size of AMA. Instead, the amount of increase in resident memory size is decided by how much memory
actually gets allocated from AMA.
Relation between pa_maxssiz_32|64bit, and Aries Parameters
32-bit Aries
At process startup time, Aries reserves space for PA-RISC application stack in AMA. The maximum size
of PA-RISC application stack is computed as follows:
max_pa_stack_size = least of following two factors:
1. ti_current value in structure of type tuneinfo2_t value defined in
/usr/include/sys/dyntune.h by making system call tuneinfo2 with parameter
maxssiz.
Section 5−−46 Hewlett-Packard Company − 7 − HP-UX 11i Version 2: September 2004