topic Re: maxdsiz max and maxdsiz_64 max in Operating System - HP-UX

maxdsiz max and maxdsiz_64 max

Andrew Luis Arruza — Mon, 13 May 2002 19:28:42 GMT

Is there a maximum size you can set the maxdsiz?
If you have a 32bit app and you have the maxdsiz_64 bit set at about double the maxdsiz does that have an affect on the 32bit app?
Sure appreciate any input.
As always answers greatly appreciated and points will be given promptly.
Thanks,
Andy

Re: maxdsiz max and maxdsiz_64 max

Sanjay_6 — Mon, 13 May 2002 19:32:59 GMT

Hi Andrew,

Try this link for more info on maxdsiz,

http://docs.hp.com//hpux/onlinedocs/os/KCparam.MaxDsiz.html

There is a max value to maxdsiz that you can set. It is there in the link. A 32 bit application should not be affected by madsiz_64bit parameter.

Hope this helps.

Regds

Re: maxdsiz max and maxdsiz_64 max

S.K. Chan — Mon, 13 May 2002 19:43:30 GMT

Q1 :-

Minimum: 0x400000 (4 Mbytes)
Maximum: 0x7B03A000 (about 2GB)

Q2 :-

No

Re: maxdsiz max and maxdsiz_64 max

Andrew Luis Arruza — Mon, 13 May 2002 19:47:33 GMT

Sanjay,
The link gave me the exact answer I was looking for.
Thanks to all, Andy

Re: maxdsiz max and maxdsiz_64 max

Bill Hassell — Tue, 14 May 2002 01:06:41 GMT

maxdsiz is a fence. It is only used to prevent runaway programs from consuming all RAM and then swap space. As mentioned, the minimum and maximum values are 4megs and 2Gb respectively. Now setting maxdsiz to 2Gb is no guarentee that a program can grow that large...special steps are needed to grow beyond 940 megs. See the white papers on memory management and process management in /usr/share/doc. Look for the keyword: magic

maxdsiz sets a limit on 32bit apps--period. maxdsiz_64 limits only 64bit programs. There is no interaction between the parameters and setting a large value has no effect on any process other than allowing to grow larger.

Re: maxdsiz max and maxdsiz_64 max

Ted_5 — Fri, 14 Mar 2003 15:27:57 GMT

On HP11 docs I see maxdsiz as 4GB
and 4396 GB for maxdsiz_64

Is this correct or is it 2GB?

also what about HP 10.2 is it the same?

Thanks

Re: maxdsiz max and maxdsiz_64 max

Ted_5 — Fri, 14 Mar 2003 19:46:02 GMT

O.K.

I think I got it:

maxdsiz

This is the max data segment size per process

The size should a multiple of 4096 ( The system pagesize)

the maximum mazdsiz is:

For HP11.11 -> 4294963200 -> 0xFFFFF000

For HP 11.0 -> 3221225472 -> 0Xc0000000

For HP 10.20 -> 2063835136 -> 0X7B03A000

Re: maxdsiz max and maxdsiz_64 max

Bill Hassell — Fri, 14 Mar 2003 20:19:18 GMT

That is correct. However, your 32bit program will abort due to lack of memory long before it hits those limits. To see why and what you can do to inmprove addressability in a 32bit program, go to /usr/share/doc on 10.20 and 11.0 (11i had the white papers removed) and print the 2 docs on memory management and process management.