Re: 2.4.28 -> ch..ch...changes....

Nick Warne
2004-11-24T23:05:57Z

On Wednesday 24 November 2004 17:48, Hugh Dickins wrote:
> On Wed, 24 Nov 2004, Marcelo Tosatti wrote:
> > On Tue, Nov 23, 2004 at 09:36:36PM +0000, Nick Warne wrote:
> > > I updated three boxes today to 2.4.28 (from .27), one at work, and two
> > > here at home (Redhat 7.1+, Slackware 10)
> > >
> > > I am intrigued terribly by the small footprint of memory usage now. I
> > > have gone through the changes file, but can really see nothing (to me,
> > > a n00b) that would alter that?
> > >
> > > Can anyone enlighten me?
> >
> > What do you mean by "memory usage"? SLAB (/proc/slabinfo) buffers
> > or pagecache ?
> >
> > Whats your workload and what drivers are you using ?
> >
> > Nothing that I am aware of explains this.
>
> _If_ it's a reduction in /proc/slabinfo's dentry_cache, and
> _if_ these boxes do a lot of removing files from tmpfs,
> then it would be the "tmpfs: stop negative dentries".

I dunno, no real scientific measures at all, but I have noticed using 'free'
all boxes from boot load load like 40% less in memory. As time goes on,
memory usage grows (of course), but now it 'drops off' when not being used...
2.4.2x never done that.

I tested today on my Slackware box especially:

Linux linuxamd 2.4.28 #1 Tue Nov 23 17:46:52 GMT 2004 i686 unknown unknown
GNU/Linux (HM, append="1280M").

An Athlon 1.2Ghz running all up to date Slack 10 stable with KDE 3.3.0
upgrade.

I ran Celestia for over an hour, burnt a few knoppix ISO's, and then ISO'ed a
big directory to burn all using 'BashBurn'.

Just played Quake2 for three maps running full chat.

Normally memory slowly fills up, perhaps using swap for a bit under these
circumstances - but looking afterwards:

root@linuxamd:~# free
total used free shared buffers cached
Mem: 1292348 520012 772336 0 38596 327304
-/+ buffers/cache: 154112 1138236
Swap: 1959888 0 1959888

I would normally expect 'free' to report 900000 odd (with Celestia pushing
toward swap) by now... but it doesn't.

Another box,:

Linux quake.ddayuk.dyndns.org 2.4.28 #1 Tue Nov 23 17:28:32 GMT 2004 i686
unknown

Runs a Quake2 server and Teamspeak. Again, usually after 2 hours uptime
nearly hits peak, but now:

total used free shared buffers cached
Mem: 516440 45368 471072 0 6296 25556
-/+ buffers/cache: 13516 502924
Swap: 265032 0 265032

The box at work is a back-up httpd (apache) web server running NTPD for whole
sub-net, mrtg, and a lot of other stuff (I use for testing stuff until I push
to main web server)... this always has 30/40MB disk swap. Today only 6MB.

I build all kernels with no modules, all built in (expect USB for memory
sticks on slack). The only change I done this time from previous kernel
upgrades was download the full 2.4.28 bz2 file rather than apply patches to
existing build trees (make oldconfig).

But whatever, I am impressed indeed - somethings changed for the good!!!