Is VHANDFRAC --> VHANDL dynamic?

[Piercarlo Grandi]

In article <565 at oglvee.UUCP> jr at oglvee.UUCP (Jim Rosenberg) writes:

   In <PCG.90Jul7174558 at odin.cs.aber.ac.uk> pcg at cs.aber.ac.uk (Piercarlo
   Grandi) writes:

   >Unfortunately the System V paging and swapping policies *stink* as Bach
   >regretfully hints, 

   I've also observed what appears to be a kind of *deadlock*.  I have
   a batch database job running -- *extremely* disk intensive.

I gues most of that is paging. Use vsar or the recently posted mon or
u386mon programs (THANKS! they are both great) to see the swap rates
and the system time expended by the swapper/pager, and horrify.

   All of a sudden the hard disk light goes out, even though the job
   has not finished.  The system is just "stuck"!  If I toggle to
   another virtual terminal with a getty running on it and press
   RETURN, woila, the batch job comes suddenly unstuck.  Most
   disconcerting.

Oh no. This is actually very common -- happens to me all the time. It
is the stinkiest problem with the swapper. The swapper goes nuts, even
if the working set of the application is smaller than "available" real
memory. We have discussed it to death, and Chen from AT&T insists that
my most horrible suspicion (expansion swapping!) is unfounded.  If it
is not like that, I wonder what it can be.

Switching to another vt and typing return will case the process
attached to it (shell, getty, anything) to be rescheduled, memory to
get shuffled, the swapper to be called, and since the memory layout
will have changed, the deadlock will cease to exist.

The only "solution" is to make sure that there is around 2-3 times more
real memory than the combined size of all active working sets, e.g. to
let memory lie around 70 percent unused on average.
--
Piercarlo "Peter" Grandi           | ARPA: pcg%cs.aber.ac.uk at nsfnet-relay.ac.uk
Dept of CS, UCW Aberystwyth        | UUCP: ...!mcsun!ukc!aber-cs!pcg
Penglais, Aberystwyth SY23 3BZ, UK | INET: pcg at cs.aber.ac.uk