Trading off safety and performance in the kernel

Posted May 14, 2015 21:42 UTC (Thu) by mjg59 (subscriber, #23239)
In reply to: Trading off safety and performance in the kernel by zlynx
Parent article: Trading off safety and performance in the kernel

If the system is in any kind of state where it has an effectively unbounded amount of work to perform then the situation changes pretty significantly. There are various cases where apps behave badly when they lose network connectivity and spin trying to reconnect, for instance.

Trading off safety and performance in the kernel

Posted May 14, 2015 23:47 UTC (Thu) by dlang (guest, #313) [Link] (1 responses)

That's not the issue. The example given is that a machine running at max speed for 10 min will overheat while one running for several hours at the low speed will not.

for this example, race to idle fails if it takes too long because the system will overheat, while running at a lower speed, even if it takes a lot more time and power will succeed and not damage things.

race-to-idle requires a very specific combination of power/performance at the different states (full speed, partial speed, and idle). That combination has not always been the case and there's no reason to believe that it is going to continue to always be the case. Idle does not always mean that it requires zero power (even for the component that's idled, let alone for the entire system)

Trading off safety and performance in the kernel

Posted May 15, 2015 5:04 UTC (Fri) by mjg59 (subscriber, #23239) [Link]

> The example given is that a machine running at max speed for 10 min will overheat while one running for several hours at the low speed will not.

Uh? I'm possibly missing something here, but I don't see any references to that example.