Re: PROBLEM: high load average when idle

From: Arjan van de Ven
Date: Tue Oct 02 2007 - 18:40:27 EST


Linus Torvalds wrote:

I wonder if the whole "round_jiffies()" thing should be written so that it never rounds down, or at least never rounds down to before the current second!

that's what it is supposed to do already...

166
167 if (j <= jiffies) /* rounding ate our timeout entirely; */
168 return original;
169 return j;
170 }

so there is always a gap of at least 1 jiffie no matter what



I have to say, I also think it's a bit iffy to do "round_jiffies()" at all in that per-CPU kind of way. The "per-cpu" thing is quite possibly going to change by the time we actually add the timer, so the goal of trying to get wakeups to happen in "bunches" per CPU should really be done by setting a flag on the timer itself - so that we could do that rounding when the timer is actually added to the per-cpu queues!

it's pretty much the same thing though
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