> + On 12-Jul-04 20:08:39
+Casper H.S. Dik <Casper.Dik@Sun.COM> wrote

>The UltraSPARC III and later CPUs have built-in memory controllers;
>each of these controllers can address 4 banks of 4GB each, for
>a maximum of 16GB of memory.

>But this is not a limitation of the amount of memory a single
>process can use; the CPU will just go elsewhere to access the
>other memory (on the bigger systems, that is)

Hmm.. This might be a stupid question but only out of curiosity..

On the larger sun systems you can change CPU's while the machine is up,
as far as I understood it it works like that when you want to remove
a CPU-card it first moves all processes and tasks in memory (at that card)
to another CPU-card (wich might move it out on swap), and then finally
tell you that the card is ready to to be removed/replaced.

What if one of the tasks using a larger block of memory than one single
CPU can handle, and the machine only had two CPU-modules ?

Casper H.S. Dik <Casper.Dik@Sun.COM> wrote in message news:<40f3108d$0$42417$e4fe514c@news.xs4all.nl>...

>
> This looks like the process has a resident set size it is comfortable
> with; however, the remaining swap space is rather low and that is
> an issue (not so much for the process in question but for the
> system itself).
>

The default swap partition on this machine was only 512 megabytes (it
came with 2 gigabytes of RAM). We made this 18 gigabytes of swap,
which is comfortably more than the 16 gigabytes of real ram that we
had installed.

After this change the system was more than willing to make nearly 15
gigabytes of memory resident for a single process and we seem to be
doing fine.

Thank you all.

Daniel Feenberg

Casper H.S. Dik <Casper.Dik@Sun.COM> wrote in message news:<40f3108d$0$42417$e4fe514c@news.xs4all.nl>...

>
> This looks like the process has a resident set size it is comfortable
> with; however, the remaining swap space is rather low and that is
> an issue (not so much for the process in question but for the
> system itself).
>

The default swap partition on this machine was only 512 megabytes (it
came with 2 gigabytes of RAM). We made this 18 gigabytes of swap,
which is comfortably more than the 16 gigabytes of real ram that we
had installed.

After this change the system was more than willing to make nearly 15
gigabytes of memory resident for a single process and we seem to be
doing fine.

Thank you all.

Daniel Feenberg

Glenn <glenn@IREPORTEVERYSPAMMER.canit.se> writes:

>On the larger sun systems you can change CPU's while the machine is up,
>as far as I understood it it works like that when you want to remove
>a CPU-card it first moves all processes and tasks in memory (at that card)
>to another CPU-card (wich might move it out on swap), and then finally
>tell you that the card is ready to to be removed/replaced.

>What if one of the tasks using a larger block of memory than one single
>CPU can handle, and the machine only had two CPU-modules ?

It's one of the wonders of virtual memory; obviously you need sufficient
resources to cope with the sudden drop in available virtual memory.

The system may start paging wildly because it no longer has sufficient
memory and you may not be able to quiesce the board if the system
does not have sufficient resources to deal with the current workload.

Casper
--
Expressed in this posting are my opinions. They are in no way related
to opinions held by my employer, Sun Microsystems.
Statements on Sun products included here are not gospel and may
be fiction rather than truth.