There should be a page listing ways to get system statistics, how to interpret them, and some example/expected values.

IRC, frenode, #hurd, 2012-11-04

<mcsim> Hi, is that normal that memory cache "ipc_port" is 24 Mb already?
  Some memory has been already swapped out.
<mcsim> Other caches are big too
<braunr> how many ports ?
<mcsim> 45922
<braunr> yes it's normal
<braunr> ipc_port              0010      76   4k    50  45937 302050
  24164k       4240k
<braunr> it's a bug in exim
<braunr> or triggered by exim, from time to time
<braunr> lots of ports are created until the faulty processes are killed
<braunr> the other big caches you have are vm_object and vm_map_entry,
  probably because of a big build like glibc
<braunr> and if they remain big, it's because there was no memory pressure
  since they got big
<braunr> memory pressure can only be caused by very large files on the
  hurd, because of the limited page cache size (4000 objects at most)
<braunr> the reason you have swapped memory is probably because of a glibc
  test that allocates a very large (more than 1.5 GiB iirc) block and fills
<mcsim> yes
<braunr> (a test that fails with the 2G/2G split of the debian kernel, but
  not on your vanilla version btw)

IRC, frenode, #hurd, 2013-01-26

<braunr> ah great, one of the recent fixes (probably select-eintr or
  setitimer) fixed exim4 :)