davef@lakesys.UUCP (Dave Fenske) (08/05/89)
Pardon the cross posting, but I am curious as to how much of this is peculiar to Xenix, and how much of it is Unix. When there is a disk intensive program running, if there is a lot of sequential I-O, the performance level of SCO Xenix seems to drop to nill (NULL). This appears to be true, even if the offending process does not consume a lot of cpu resources. I've tried to run processes like that at a lower priority, but the results were only marginally better. I've also heard of this problem from other individuals. How much of this problem is unique to Xenix. Is there a solution? My speciffic problem is that when I build an 8 meg file, no other process gets any service for sometimes 30 seconds. This with just two users on a 16 MHz 386, w/ 4.5 megs of RAM and a hundred meg RLL disk. DF
steve@nuchat.UUCP (Steve Nuchia) (08/11/89)
In article <932@lakesys.UUCP> davef@lakesys.UUCP (Dave Fenske) writes: >When there is a disk intensive program running, if there is a lot of sequential >I-O, the performance level of SCO Xenix seems to drop to nill (NULL). This I have observed a similar phenomenon on my Bell Tech 386 3.0 system. In particular, I can run dd if=/dev/dsk/0s3 of=/dev/null bs=16k for instance and absolutely nothing else gets serviced on that disk until I kill it. I interpret this as an effect of the elevator algorithm. It would have to be modified with some kind of fairness provision to prevent this behaviour. -- Steve Nuchia South Coast Computing Services uunet!nuchat!steve POB 890952 Houston, Texas 77289 (713) 964 2462 Consultation & Systems, Support for PD Software.