HP-UX Reference (11i v3 07/02) - 5 Miscellaneous Topics (vol 9)

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Aries(5)

Itanium(R)-based Systems Only

Aries(5)

• For 32-bit Aries: 215 KBytes

• For 64-bit Aries: 280 KBytes

Apart from the memory required to allocate new threads, Aries needs some memory for its internal

dynamic data structures allocation. The size of the Aries private heap is determined by the Aries parame-

ter -heap_ssz. Aries divides the heap area into two parts — the ﬁrst part is used for the Aries private

heap and the second part is used for allocation of new threads. Thus the required amount of space for the

Aries heap is calculated as follows:

Required Aries Heap Size =

-ap_heap_ssz KB + (Number of PA-RISC application threads) *

(Memory required to allocate one Aries thread, in KB)

Maximum Number of Threads that Aries Can Create

A PA-RISC application can create a maximum of 86 threads under 32-bit Aries with the default value of the

kernel tunable parameter pa_maxssiz_32bit

and default values of the 32-bit Aries parameters. The

same application can create a maximum of 439 threads under 64-bit Aries with the default value of the ker-

nel tunable parameter

pa_maxssiz_64bit

and default values of 64-bit Aries parameters.

Check to see that the value of your kernel tunable parameter

max_thread_proc

is not less than the

required number of threads that your PA-RISC application needs to create.

If your PA-RISC application needs to create a larger number of threads than the maximum number of

threads that can be created with default values of Aries parameters and the kernel tunable parameter

pa_maxssiz_32|64bit

, then increase the Aries heap size by specifying the -heap_ssz option in the

Aries resource conﬁguration ﬁle.

Note: The amount of free memory available in AMA on account of reducing a PA-RISC application’s stack

size (Aries option

-ssz) cannot be automatically used by Aries to allocate more space to the Aries heap.

To change the Aries heap size, you must set the Aries option -heap_ssz in the Aries resource

conﬁguration ﬁle.

Emulating MxN Threads

Aries supports PA-RISC applications which are linked with the MxN pthreads library. With this release of

HP-UX, the PA-RISC MxN pthreads library is delivered on Itanium-based system.

A future release of Aries may have support for true emulation of MxN pthreads. Until that time, Aries

supports emulation of PA-RISC HP-UX applications linked with MxN pthreads library in traditional 1x1

mode. Aries achieves this by internally setting the environment variable

PTHREAD_COMPAT_MODE

to 1.

EMULATING PA-RISC APPLICATION STACK UNDER ARIES

The stack allocated by the Itanium-based HP-UX kernel is used by Aries as its own native stack. Aries allo-

cates the stack for PA-RISC applications from AMA. Most PA-RISC applications run as expected with

default stack size set by Aries. However, if your PA-RISC application fails with core dump, with the fol-

lowing error message, then you should increase the PA-RISC application stack size by using Aries option

-ssz in the Aries resource conﬁguration ﬁle.

ARIES32|64 Limitation/Error

PID xxxxx received SIGSEGV for stack growth failure

Possible causes - insufficient memory or swap space,

or stack size exceeded pa_maxssiz_32|64bit

Aries does not support applications which are nearly or completely

maxed out on their data segment address space usage.

This is because

Aries consumes small amount of virtual memory address space of

application

Terminating emulation

HP-UX 11i Version 3: February 2007 − 10 − Hewlett-Packard Company 73