Re: Why ping latency is smaller with shorter send interval?

From: Willy Tarreau
Date: Fri Oct 02 2020 - 05:56:53 EST


On Fri, Oct 02, 2020 at 11:26:00AM +0200, Eric Dumazet wrote:
> 2) Idle cpus can be put in a power conserving state.
> It takes time to exit from these states, as you noticed.
> These delays can typically be around 50 usec, or more.

This is often the case in my experience. I'm even used to starting a
busy loop in SCHED_IDLE prio on certain machines or in certain VMs
just to keep them busy, and to see the ping latency cut in half.

Willy