Messages in this thread | | | Date | Sun, 4 May 2014 20:40:16 +0200 | From | Ingo Molnar <> | Subject | Re: [RFC/HACK] x86: Fast return to kernel |
| |
* Andy Lutomirski <luto@amacapital.net> wrote:
> > That said, regular *device* interrupts do often return to kernel > > mode (the idle loop in particular), so if you have any way to > > measure that, that might be interesting, and might show some of > > the same advantages. > > I can try something awful involving measuring latency of > hardware-timed packets on a SolarFlare card, but I'll have > calibration issues. I suppose I could see if 'ping' gets faster. > In general, this will speed up interrupts that wake userspace from > idle by about 100ns on my box, since it's presumably the same size > and the speedup per loop in my silly benchmark.
To simulate high rate device IRQ you can generate very high frequency lapic IRQs by using hrtimers, that's generating a ton of per CPU lapic IRQs.
Thanks,
Ingo
| |