Messages in this thread |  | | | Date | Mon, 16 Nov 1998 06:16:00 -0500 (EST) | | From | Robert Minichino <> | | Subject | Elevator vs first-come-first-served |
| |
The modified elevator algorithm as currently used is more than adequate for most workstation and light server use; it's reasonably fair, and most workstation disk drives do little to no reordering (buffers on typical IDE drives range from 64-512k). However, with an intelligent caching disk controller (either on the HBA, or a SCSI-SCSI RAID controller), the sorting of disk blocks can actually decrease performance. Granted, I haven't poked around in the Linux disk code too much recently, but I wonder how difficult it would be to make either a kernel or runtime option to disable the elevator algorithm and instead use simple first-come first-served seek optimization. This way the intelligent controllers that -do- know the physical geometry of the disks can do their job, and we can still accelerate disk accesses on systems lacking this luxury (most of them). Just my US$0.02.
-- Robert Minichino Chief Engineer Denarius Enterprises, Inc.
- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.rutgers.edu Please read the FAQ at http://www.tux.org/lkml/
|  |