Developers Linus Torvalds and Andrew Morton, both of the Open Software Development Lab, are claiming speed hikes of...
up to 1,000% for the Linux 2.6 kernel.
The main claim for the kernel's improved I/O scheduling is that it can increase database workload processing by as much as 15%.
The improvements are the result of minimising disc head movement during concurrent reads. Linux founder Torvalds reportedly said, "Basically, the anticipatory scheduler maintains some per-process statistics to try to guess whether there will be another dependent read 'soon'."
If the algorithm guesses that there will be another read access, it will wait before returning to process the next request.
"This significantly decreases the back-and-forth seeking under some loads," the report continued. "The wait-before-seek enables one process to perform several similar reads in rapid succession without having to send the drive head back and forth repeatedly. The anticipatory scheduler is best suited to standard desktop and file server loads. In fact, it was while using the anticipatory scheduling that Morton experienced up to 1,000% speed increases on some workloads."
The second, Deadline Scheduler, adds two queues, FIFO read and FIFO write and adds the claimed "1,000%" performance only on desktop-type loads. Database loads experience improvements of up to 15%, according to Morton.
"The deadline scheduler is faster for the short-and-seeky style database workloads, sometimes by up to 15%," he said.
The end result is to make desktop applications more responsive to end users because they do not have to wait as long in the queue for attention from the CPU.
Manek Dubash writes for Techworld.com