INN with hyperthreading/SMP

"Miquel van Smoorenburg" list-inn-workers at
Tue May 11 08:04:53 UTC 2004

In article <EA6FEF43F6A4954BEE51FAF5 at>,
Mike Zanker  <mike-dated-1084856314.4f772a at> wrote:
>are there any known problems with running INN (2.4.1) on a box with a 
>hyperthreading CPU and SMP linux kernel?

That's what I'm running.

>I've built a box to replace my aging feeder with a P4 HT processor and 
>have installed Red Hat Enterprise Linux 3. The SMP kernel was installed 
>by default (2.4.21 with RH mods). I built INN with perl and largefiles 
>so that I could have CNFS buffers >2GB.
>The new box is currently receiving a feed from the feeder but innd is 
>growing at an alarming rate. After a few hours it was using about 350MB 
>RAM. On my reader box (same OS but single P3 processor) with the same 
>feed, innd never gets above about 50MB. Both boxes have 512MB RAM.
>I've rebooted with a non-SMP kernel to see if it makes any difference 
>but wondered whether this was a known issue.

It's not the kernel. You built INN with largefile support. Lots of
internal (in-memory) and external (on-disk: history file hashtable)
structures now double in size because of 32/64 bit issues.

Another thing is that you rebuilt INN and it may now use mmap() in
places where it used read()/write() before. That shows up under VSZ
in the ps aux output, but that's quite misleading. mmap()ed memory
can be compared with disk cache - if the memory is needed for
other purposes, the mmap() dirty pages will be written to disk.
That's the difference between VSZ and RSS.


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