Re: apache and threading (was Re: www.jpl.nasa.gov)

[Randy Terbush <ra...@zyzzyva.com>]

> On Sun, 6 Jul 1997, Marc Slemko wrote:
> 
> > Sigh.  I'm trying to think of a way for FreeBSD, but all I have come up
> > with is using the kernel debugger, which isn't exactly the greatest thing.
> 
> Hmm.  procfs gives me:
> 
> 0x1000     0x36000           45         0 r-x COW vnode
> 0x36000    0x38000            2         2 rwx COW vnode
> 0x38000    0x93000           45         7 rwx COW swap
> 0x93000    0x98000            0         0 rwx COW swap
> 0x98000    0xa0000            5         5 rwx     default
> 0x8036000  0x8044000         10         0 r-x COW vnode
> 0x8044000  0x8046000          2         0 rwx COW vnode
> 0x8046000  0x804f000          5         2 rwx COW swap
> 0x8050000  0x8053000          3         0 r-x COW vnode
> 0x8053000  0x8054000          1         0 rwx COW vnode
> 0x8054000  0x8065000          0         0 rwx     none
> 0x8065000  0x80c6000         68         0 r-x COW vnode
> 0x80c6000  0x80ca000          4         3 rwx COW vnode
> 0x80ca000  0x80e1000          9         8 rwx COW swap
> 0x80e1000  0x80ed000         12         0 rwx     default
> 0xefbde000 0xefbfe000         5         4 rwx COW swap
> 
> (on a httpd process, with a moderate set of modules compiled in)
> 
> When I add that up, I get 151552 bytes non-COW.  Everything still COW
> is presumably just a reference to a shared physical page, so I don't
> care about it.
> 
> I do wonder about the map entry  with the type of "none" though;
> I'm not sure what the vm system does with that.  It isn't standard
> BSD any more, I think dg did a bunch of changes there.  That map
> entry may be bogus, in which case it could drop to 81920 bytes,
> plus process overhead of course.

I'd be interested to learn dg's explanation of this. I have bee 
staring at some strange swap behavior over the past several months 
that keeps leading me back to these map entries. I've referred to it 
as a swap leak where a restart seems to free up the swap area for a 
few hours.

> Interesting.  I will have to look at my numbers again.  This does not
> agree with my experience.