Grant Edwards <invalid@invalid.invalid>: > On 2015-09-11, Chris Angelico <ros...@gmail.com> wrote: >> This is what I meant when I said you would be polling. Effectively, >> you wake up your program every half-second, check if Ctrl-C has been >> pressed, and if it hasn't, you go back to sleep again. This is pretty >> inefficient. > > Though it offends one's engineering sensibilities[1], it's just not > that inefficient. I'd bet money you won't even be able to measure the > difference in CPU usage. Waking up twice per second and immediately > calling select() again on any hardware/OS built in the past 50 years > is going completely negligible (as long as you can ignore the smell). > > Even waking up ten times per second won't be noticeable. > > Waking up every millisecond or two might be noticeable.
It can add up. In particular, it can prevent the CPU from staying in the low-power mode, especially on battery-powered devices. <URL: https://lwn.net/Articles/549580/> Another environment where such polling circuses can actually overwhelm a CPU is virtual machines. When dozens or hundreds of VMs are each polling left and right, the host may not get much actual work done. Marko -- https://mail.python.org/mailman/listinfo/python-list
