Alan Altmark wrote: > Today we tout > the mainframe as being best-of-breed for context switching. But > what triggers those context switches? Interrupts, of course. > Timers. I believe you are referring to Linux context switches, as measured with lmbench. The mainframe is very fast with those indeed, but the benchmark is about switching from one user context to another user context, which is done once scheduler decides to run a different task. In Linux, interrupts are not called context switch, just "interrupt".
Btw: some interrupts lead to a context switch, when a user process was waiting for an event (disk read via read() syscall for example). The interrupt handler wakes the user context, and the scheduler is likely to run this task for fairness reason: the task has not computed for some time, it was waiting for I/O to complete while other tasks enjoyed the CPU horsepower. cheers, Carsten -- Carsten Otte has stopped smoking: Ich habe in 4 Monate, 1 Woche und 2 Tage schon 636,45 Euro gespart anstatt 2.651,88 Zigaretten zu kaufen. ---------------------------------------------------------------------- For LINUX-390 subscribe / signoff / archive access instructions, send email to [EMAIL PROTECTED] with the message: INFO LINUX-390 or visit http://www.marist.edu/htbin/wlvindex?LINUX-390
