On Mon, 2007-10-09 at 10:20 +0100, James Chapman wrote: > jamal wrote: > > > If the problem i am trying to solve is "reduce cpu use at lower rate", > > then this is not the right answer because your cpu use has gone up. > > The problem I'm trying to solve is "reduce the max interrupt rate from > NAPI drivers while minimizing latency".
As long as what you are saying above translates to "there is one interupt per packet per napi poll" then we are saying the same thing. > In modern systems, the interrupt > rate can be so high that the CPU spends too much time processing > interrupts, resulting in the system's behavior seen by the user being > degraded. modern systems also can handle interupts a lot better. If you can amortize two packets per interupt per napi poll then you have done better than the breakeven point; however, I think it is fair to also disprove that in modern hardware the breakeven point is met with amortizing two packets. > Having the poll() called when idle will always increase CPU usage. But > the feedback you and others are giving encourages me to find a better > compromise. i dont mean in any way to discourage you - just making you work better ;-> It is very refreshing to see that you understand the scope is performance not vomiting endless versions of code - and for this i feel obligated to help. > I'll go away and do some tests. I'll post results here for discussion later. way to go. cheers, jamal - To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html
