Re: [Bug-gnubg] OT - Linux performance

[Achim Mueller]

* Jim Segrave wrote on 01 Okt 2003:

> For the last couple of months, I have been running Linux instead of
> FreeBSD on my home laptop - specifically RedHat 9. I have to say, the
> performance has been very disappointing and I wonder if I'm simply
> setting some sub-optimal configuration or if there's a serious
> performance issue in the handling of memory and swap.
> 
> The symptoms are simple - I use fvwm set up to give me 8 desktops. The
> machine has 128Mb of Ram and a 700Mhz processor. When I have for
> example, gnubg building in an xterm on one desktop, Opera (or Mozilla,
> Konqueror or Galeon) full screen in another desktop and mail and
> perhaps another xterm or two in a third, then switching between
> desktops is painfully slow - 30 seconds or more while the browser
> reloads from/is written out to swap, 15 seconds or more when moving
> from the compile desktop to the mail reader one. Looking with top, I
> see generally that there's 100 to 125Mb of swap in use and that
> current memory is quite full.

Can you give me the output of

#: free
#: sar 2 20
#: uptime (I only need the load average)

perhaps simultaneously, when switching desktops? Don't trust in
"top" too much, depending on the kernel version it seems to be a bit
buggy (at least on smp machines at work).

> Under FreeBSD, this simply doesn't happen. The main differences I see
> are that little gets put into swap and that X has a size of about 30Mb
> with FreeBSD, 90+ Mb with Linux. It is not possible to run two gnubg's
> simultaneously under Linux, the disc never stops running unless I
> reduce the cache size to under 100,000, even then it's marginal. 

Here X has round about 160m (xfree 4.4.3, kde-3.1.4), but I have
512mb RAM and no problems even with vmware4 running.

> (a minor nit - the evaluation speed is 7600/sec under FreeBSD, gcc
> 3.2, -O3 and about 7200~7300 under Linux, which I as I recall, can't
> check as I've rebooted into FreeBSD and it can't read ext3fs) is gcc
> 3.3, also using -O3.
> 
> I know there are several Linux users out there - has anyone else seen
> similar behaviour where it seems to always be swapping active
> processes out to disc and pulling them back again randomly?

Did you install all redhad network updates? I know that there was at
least one kernel update in rh9.

Ciao

Achim

-- 
achim mueller, anne-frank-str. 25, D-48431 rheine
+49 (0)5971 83767, +49 (0)163 8458340
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