SUMMARY: 3/50 & XKernel going slowly

From: Dave Mitchell (
Date: Mon Apr 05 1993 - 20:35:40 CDT

original question:
we have been successfully using 3/50s as X-terminals using the XKernel 1.5
package. However, we've noticed that after some use, they grind to a near-halt.
Running etherfind reveals that just moving the mouse a bit in the root window
causes several pages of the Xsun executable to be paged in over the net.
This would seem to explain the slowness. The question is, how do
I stop this? I presume that in some way as more windows are created, more
RAM is used up, and large chunks of the Xsun binary are flushed from memory,
and must be repaged in each time they are accessed.


* what do expect using 3/50's with 4Mb RAM

* "You might want to consider moving to Xkernel 2.0. It is currently in
  pre-alpha test (see alt.sys.sun), but if nothing major happens, it
  will be formally released this or next week.
  2.0, among other things, uses the null swap file so that SunOS is
  fully memory resident. This will certain prevent paging :-)"

* Xsun can be made to use less memory by running with -bs -su to turn of
  Backing Store and Save Unders. Also, avoid virtual window managers like
  tvtwm, olvwm if possible.

* patch the kernel as follows:
        # adb -w vmunix.Xkernel
        nosched?W 1
        (this would probably have to be done on a sun3 to patch a sun3 binary)
  Apparently this stops SunOS 4.x's over-zealous paging algorithm
  paging out anything that hasnt "moved" in the last few minutes

* make sure the swap file is at least 4Mb

Well, apart from checking my swap file _is_ 4Mb, I havent had a chance to try
any of these out yet. But they are all interesting, so I included them all.

Thanks to:
(Seth Robertson) seth <seth@edu.columbia.ctr>
jsin@EDU.UCLA.JANET (John Sin) (Daniel Trinkle)
David Wiseman <magi@ca.uwo.csd>


* David Mitchell, Systems Administrator, email:
* Dept. Computer Science, Sheffield Uni. phone: +44 742-825573
* 211 Portobello St, Sheffield S1 4DP, UK. fax: +44 742-780972
* Standards (n). Battle insignia or tribal totems

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