Xref: utzoo comp.unix.wizards:22911 comp.unix.i386:6939 comp.sys.att:10001 Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!uunet!mcsun!ukc!dcl-cs!aber-cs!odin!pcg From: pcg@cs.aber.ac.uk (Piercarlo Grandi) Newsgroups: comp.unix.wizards,comp.unix.i386,comp.sys.att Subject: Re: Is VHANDFRAC --> VHANDL dynamic? Message-ID: Date: 17 Jul 90 11:45:33 GMT References: <562@oglvee.UUCP> <565@oglvee.UUCP> Sender: pcg@aber-cs.UUCP Organization: Coleg Prifysgol Cymru Lines: 41 In-reply-to: jr@oglvee.UUCP's message of 11 Jul 90 22:18:51 GMT In article <565@oglvee.UUCP> jr@oglvee.UUCP (Jim Rosenberg) writes: In pcg@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@nsfnet-relay.ac.uk Dept of CS, UCW Aberystwyth | UUCP: ...!mcsun!ukc!aber-cs!pcg Penglais, Aberystwyth SY23 3BZ, UK | INET: pcg@cs.aber.ac.uk