From mboxrd@z Thu Jan 1 00:00:00 1970 From: jamal Subject: Re: NAPI, e100, and system performance problem Date: Mon, 18 Apr 2005 08:14:55 -0400 Message-ID: <1113826496.7419.78.camel@localhost.localdomain> References: Reply-To: hadi@cyberus.ca Mime-Version: 1.0 Content-Type: text/plain Content-Transfer-Encoding: 7bit Cc: netdev@oss.sgi.com Return-path: To: "Brandeburg, Jesse" In-Reply-To: Sender: netdev-bounce@oss.sgi.com Errors-to: netdev-bounce@oss.sgi.com List-Id: netdev.vger.kernel.org Jesse, I doubt your problem has to do with interrupt rates. If you say the CPU is "fast" - then the problem is elsewhere. A fast machine that cant handle 77K interupt/sec would be a pathetic one. It could be the PCI IO rate which such a fast system shouldnt have issues handling. You say it can process upto two packets/interupt -so thats pretty fast. Actually it could be the e100 issue - try replacing the NIC with e1000 and repeat your tests and see if you observe the same issues. If you are doing the netperf tests then collect netstat -s output; /proc/net/softnet_stat is another useful stat to look at. cheers, jamal On Sun, 2005-17-04 at 23:11 -0700, Brandeburg, Jesse wrote: > _Summary_ > As the part owner of the e100 driver, this issue has been nagging at me > for a while. NAPI seems to be able to swamp a system with interrupts > and context switches. In this case the system does not respond to > having zero cpu cycles available by polling more, as I figured it would. > This was mostly based on observation, but I included some quick data > gathering for this mail. >