> -----Original Message----- > From: [EMAIL PROTECTED] > [mailto:[EMAIL PROTECTED] On Behalf Of Andi Kleen > Sent: Wednesday, February 01, 2006 10:45 PM
> There was already talk some time ago to make NAPI drivers use > the hardware mitigation again. The reason is when you have a > workload that runs below overload and doesn't quite fill the > queues and is a bit bursty, then NAPI tends to turn on/off > the NIC interrupts quite often. At least on some chipsets > (Tigon3 in particular) this seems to cause slowdowns compared > to non NAPI. The idea (from Jamal originally iirc) was to use > the hardware mitigation to cycle less often from polling to > non polling state. > > Don't think it was ever implemented though. In the end we > just eat the slowdown in that particular load. Ideally, we want NAPI to set driver interrupt rate dynamically, to a desired number of packets per interrupt. More and more NICs support this in hardware as a run-time option; switching interrupts ON and OFF is indeed a bit of an "overdrive" but can be still used for legacy NICs. - 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
