topic Re: Help regarding kernel parameter change in Operating System - HP-UX

Help regarding kernel parameter change

raiden — Wed, 23 Jan 2008 11:37:32 GMT

Hi

I have received a change from customer to change following kernel parameters

maxdsiz 0xF9000000
maxssiz 0x04D00000
maxdsiz_64bit 0x0000039999999999
maxssiz_64bit 0x04D00000

At this moment the above kernl parameteres have following values ( from kctune command)

maxdsiz 1073741824
maxdsiz_64bit 4294967296
maxssiz 8388608
maxssiz_64bit 268435456

The current value seems to be in decimal but the values given by customer are in hexadecimal. Now if I convert the hexadecimal values to decimal. i get a very huge number which doesnt seem to be correct.

Can some one let me know if the conversion I am doing is correct or is it some thing i am doing wrong.

Re: Help regarding kernel parameter change

Pete Randall — Wed, 23 Jan 2008 11:40:53 GMT

I believe SAM will do the conversion for you, showing either decimal or hex at your request.

Pete

Re: Help regarding kernel parameter change

Don Morris_1 — Wed, 23 Jan 2008 12:20:03 GMT

kctune should take the request in hex as well as decimal. Though I don't know what they're going for with that maxdsiz_64bit value.... you really should do 0x3999999a000 since non-page aligned [assuming the usual 4kb page size here] values of the tunable are really rounded down in the kernel (which keeps track of these things internally in page units, not bytes).

Re: Help regarding kernel parameter change

Dennis Handly — Wed, 23 Jan 2008 12:23:08 GMT

>I have received a change from customer to maxdsiz_64bit 0x0000039999999999
>Now if I convert the hexadecimal values to decimal. i get a very huge number

Yes, the maxdsiz_64bit seems bogus:
(gdb) p 0x0000039999999999 $3 = 3958241859993
(gdb) p 0x0000039999999999 / (1024 * 1024 * 1024)
$7 = 3686

That's about 3 Tb! Do you have that much swap space?

Re: Help regarding kernel parameter change

Don Morris_1 — Wed, 23 Jan 2008 15:12:40 GMT

It doesn't phase me... some folks just love spinning the knob all the way over -- they're really trying for "effectively unlimited" in most of these cases. Fortunately for maxdsiz{_64bit} there aren't really side effects (unlike maxssiz).

Re: Help regarding kernel parameter change

Rita C Workman — Wed, 23 Jan 2008 17:41:12 GMT

Sounds like yep. If you convert these from hex to decimal the numbers get very large.
maxdsiz goes to 4177526784
maxssiz goes to 80740352

...(if I entered the right number of zeroes..)

Only question to ask is "...is the customer always right ?"

Rgrds,
Rita