HP UX11 32bit Shared Memory

[Roland Leeb]

Is it true, that single 32bit process can only use 1 GB and with EXEC_MAGIC 1,75. Or have all 32bit processes a 1 Gb (1,75GB) memory limitation?

[Frederic Sevestre]

Hi,

Your processes can only use 1,75 GB with HP-UX 11.00 32bits.
If you want to use more, you will have to use the memory windowing to allow few processes to use there own window of 1,75 GB of shared memory.

Fr??d??ric

[Dietmar Konermann]

SHARE_MAGIC (default) and EXEC_MAGIC: 1.75 GB
SHMEM_MAGIC: 2.75 GB

[Roland Leeb]

Is the limitation for a single 32bit process 1 GB ( 1,75)?? Yes or no? Thanks..

[Frederic Sevestre]

Hi,

All the processes will use the same space of shared memory, exept if you use memory windowing.

Fr??d??ric

[T G Manikandan]

Yes single 32 bit exe will use max of 960 MB of memory.
If you have EXEC_MAGIC options it can extend upto 1.75GB

[Dietmar Konermann]

We are talking you shared memory, I assume. See the total limits in my post above.

There is a 1 GB also for 32bit procs: no single segment can be larger than 1 GB. So you need at least 2 segments to reach the 1.75 GB limit.

EXEC_MAGIC increases the private data space... this is something completely different.

Best regards...
Dietmar.

[Roland Leeb]

Ok, I understood. Thanks! That means, two 32bit processes can use max. 2GB...

[Dietmar Konermann]

No. :-)
The Shared Memory limits are system-wide (unless you use memory windows).

Look, the limitation is the 32 Bit address space. And since _shared_ objects share the same virtual adresses (all attached processes need to access the segments using identical 32 Bit pointers), there is a system-wide limit of 1.75 GB (2.75 GB respectively).

Regards...
Dietmar.