--8<--
> Except that openoffice and mozilla can be swapped out in BOTH cases: the
> kernel can discard mapped pages and reread as needed, whether you have a swap
> partition or not.
>
No they can't without swap, nothing can be SWAPPED out. The code pages can be
paged out (discarded), but no SWAPPING takes place.
> Whereas without swapspace, only the read-only mapped pages can be swapped out.
Again, pages do not gat swapped out, only applications can get swapped out.
Swapping is per definition the process of removing all pages used by one
application from RAM, and moving ALL pages to swap.
> Provided the VM is doing its job properly, adding swap will always be a net
> win for efficiency: the kernel is able to dump unused pages to make more room
> for others. Of course, you tend to "feel" the response times to interactive
> events, rather than the overall throughput, so a change which slows the
> system down but makes it more "responsive" to mouse clicks etc feels like a
> net win...
>
>
> James.
With any properly sized system, it will NEVER SWAP. Paging is a completely
different thing. A little paging is not a problem. Up to 70 pagescans/s on
occasion is quite acceptable. If paging activety grows above that, you may
have a real problem. I don't know about the current VM, but with most unixes
when you hit this mark, the system actually starts swapping, and your
responsiveness goes down the drain....
-- Met vriendelijke groeten,Remco Post
SARA - Stichting Academisch Rekencentrum Amsterdam High Performance Computing Tel. +31 20 592 8008 Fax. +31 20 668 3167
"I really didn't foresee the Internet. But then, neither did the computer industry. Not that that tells us very much of course - the computer industry didn't even foresee that the century was going to end." -- Douglas Adams
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This archive was generated by hypermail 2b29 : Fri Nov 23 2001 - 21:00:19 EST