Subject: Re: low-mem netbsd - found why so slow?!
To: None <email@example.com>
From: Matthias Buelow <firstname.lastname@example.org>
Date: 02/17/2001 03:10:09
>i think i found what "eats" about 3MB of memory but i do not understand
>vmstat -sm gives right sums until swap will be started.
>adding swap EATS near 700 pages!!!!
this is odd.. I just had a look at my vaxstation, which is the
only one close to 8mb I can lay my hands on (it's got 24 megs actually),
and summed up stuff:
at startup, the kernel tells me the following:
total memory = 24448 KB
avail memory = 19000 KB
using 610 buffers containing 2440 KB of memory
"top" spits out:
Memory: 6724K Act, 4012K Inact, 188K Wired, 5224K Free, 1440K Swap, 95M Swap free
and vmstat -m says:
In use 413K, total allocated 804K; utilization 51.5%
now, if I sum it up, _with the extra addition of the buffers_, I get:
Act Inact Wired Free Kern Buffers Total
6724 + 4012 + 188 + 5224 + 804 + 2440 = 19392
which at first glance looks very much like the 19 megs reported
as "avail" at bootup.
However: I always thought, "avail memory" at kernel start already
_included_ the block buffer cache, I mean, it does change when
I change buffer size options (I did so, to have a slightly larger cache.)
Over 5 megs runtime size for a rather stripped-down vax kernel would
seem a bit excessive also.
However, if the buffer cache is included in the above value, then I
shouldn't have to add the 2440K and then there would be about 2 megs
missing. Now, where are they? Is it just my confusion, some discrepancy
in certain values reported by the kernel or displayed by tools, or
is there really something missing?