Thanks for the commets. I actually use UDP because I am seeking for ways to improve the performance of IPOIB and I wanted to avoid TCP's flow control. I am really up to making anaysis. Can you tell me more about irqbalnced? Where can I find more info how to control it? I would like my interrupts serviced by all CPUs in a somehow equal manner. I mentioned MSIX - the driver already make use of MSIX and I thought this is relevant to interrupts affinity. > On Wed, 15 Nov 2006 00:15:47 +0200 (IST) > eli@xxxxxxxxxxxxxxxxxx wrote: > >> Hi, >> I am running a client/server test app over IPOIB in which the client >> sends >> a certain amount of data to the server. When the transmittion ends, the >> server prints the bandwidth and how much data it received. I can see >> that >> the server reports it received about 60% that the client sent. However, >> when I look at the server's interface counters before and after the >> transmittion, I see that it actually received all the data that the >> client >> sent. This leads me to suspect that the networking layer somehow dropped >> some of the data. One thing to not - the CPU is 100% busy at the >> receiver. >> Could this be the reason (the machine I am using is 2 dual cores - 4 >> CPUs). > > If receiver application can't keep up UDP drops packets. The counter > receive buffer errors (UDP_MIB_RCVBUFERRORS) is incremented. > > Don't expect flow control or reliable delivery; it's a datagram service! > >> The secod question is how do I make the interrupts be srviced by all >> CPUs? >> I tried through the procfs as described by IRQ-affinity.txt but I can >> set >> the mask to 0F bu then I read back and see it is indeed 0f but after a >> few >> seconds I see it back to 02 (which means only CPU1). > > Most likely, the user level irq balance daemon (irqbalanced) is adjusting > it? > >> >> One more thing - the device I am using is capable of generating MSIX >> interrupts. >> > > Look at device capabilities with: > > lspci -vv > > > -- > Stephen Hemminger <shemminger@xxxxxxxx> > - To unsubscribe from this list: send the line "unsubscribe linux-net" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
