sys_exec / memtest / mixed memory models / excessive page-in

[Diederik de Groot]

Hi Rob en Hein,

Thanks for your answers. I feel a bit better now about the machine we bought. Thanks a lot. I just thought that output was something to worry about and might maybe explain the high numbers of page-in's i was getting. Compared to our other ES-40 (running OSF 4.0f).

Now i will have to hunt for a nice drive to put my swapfile on and switch back to swap_lazy=1 i guess.

If i know we have enough memory to run all the applications in, why would i want to reserve space in the swap file and have disk I/O spent on the reservation (I know it's a-synchronous). And how would this solve my page-in's ,i don't understand quite yet.

Regards,

Diederik de Groot

[Diederik de Groot]

Hi Hein,

Read your full post again, thanks for the excellent debunking of my errors.

No more worries about my memory modelnumbers and sys_exer memtests.

I like lazy swapping as well and don't really see the need to switch over to eager either.

Funny thing is, at the moment i'm not running any non HP Tru64 OS Applications. Just the OS... and still i get hi numbers of In-Pages with the machine really doing anything. sys_check told me to check it out and i did. I know sys_check doesn't know everything, but just in case i compared it to the other ES-40 we have and it our current production machine generating less page-in under full strain.

We would like to switch over to this machine and i'm trying to be rigorous in testing and checking before taking it into production.

Having 128000 page-in after rebooting the machine 20 minutes ago was worrying to me.

At the moment things have quieted down a bit on this machine and i see less page-in's at the moment.

Running advfs defragment really put's the page faults into overdrive though... Still a little miffed about that one... I'll debunk that later i guess...

It was just something i wanted to check out and run against you guys.

It also gave me the assurance that when i need any help in the future that posting a message here will actually create a response.

Next time i'll try not to ask such "stupid" questions again. Pretty hard to find out though if your own question is "stupid" until you actually ask it. Nastiest problem with asking" stupid" questions, is that this thread will remain here on the internet until the end of time of course.

Thanks you guys,

Regards,

Diederik de Groot

[Ivan Ferreira]

Hi Diederik, please support the community by assigning points. Please see:

http://forums1.itrc.hp.com/service/forums/helptips.do?#28

[jim owens_1]

two additional things to keep in mind:

- you can not compare V4.0 and V5.1B statistics. Even comparing different PK levels on V5.1B can be misleading because there are accounting differences (i.e. counts that were wrong are now tracked correctly).

- sys_check is good for some things but notorious for being wrong about kernel tuning. It has gotten progressively more wrong since V5.0 and no effort will ever be made to fix sys_check.

[Pieter 't Hart]

the system knows about memory in terms of dimms, banks(multiple dimms) and arrays (multiple banks).
I regrouped your memory info in some other way:

SMB0.MMB0.DIM1 02 20-00ESA-08 006a1311 400 98
SMB0.MMB1.DIM1 00 20-00ESA-08 007f1311 400 98
SMB0.MMB2.DIM1 00 20-00ESA-08 00d80616 200 98
SMB0.MMB3.DIM1 00 20-00ESA-08 01750616 200 98

SMB0.MMB0.DIM4 00 20-00ESA-08 01830616 200 98
SMB0.MMB1.DIM4 02 20-00ESA-08 0120061c 200 98
SMB0.MMB2.DIM4 00 20-00ESA-08 00370616 200 98
SMB0.MMB3.DIM4 00 20-00ESA-08 00710616 200 98

as i read your info about your memory i would suggest it may form an array with all 200's (dimm3+4) but not with mixed 200/400 (dimm1+2)
this could explain some performance effect.

as for the page-in's : sys_check itself does an enormous amount of page-in's so i question if this is really a problem (same as for the number of files in /tmp)
as long as you dont exessive page-out (as in Ivan's post)

[Diederik de Groot]

Hi Pieter,

I already moved the memory models around to make one array of model 400 modules just to make sure, they were mixed before. I checked out the documentation to figure out which module to please where.

Thanks a lot, i'll check again to see if i did it right.

According to the others it should not matter as i found out after the moving around.

Regards,

Diederik