Sign Up to our social questions and Answers Engine to ask questions, answer people’s questions, and connect with other people.
Login to our social questions & Answers Engine to ask questions answer people’s questions & connect with other people.
Lost your password? Please enter your email address. You will receive a link and will create a new password via email.
Please briefly explain why you feel this question should be reported.
Please briefly explain why you feel this answer should be reported.
Please briefly explain why you feel this user should be reported.
I’m using Linux version 2.6.32.28, and I just wonder: Because there is one queue per CPU when using netif_rx(skb), and in case that the PCI-interrupt will be handled using the two of the CPU’s cores (now it uses just one, another good question is why), how is that the kernel doesn’t mess up the order of the received packages? Am I missing something?
in Linux version 2.6.32.28 there is basically NAPI is used in this case if very first packet comes then the interrupt is generated & its related handler is used to process the packet.
and the packet processing is done in basically in two parts …
1-> hard interrupt in this case the packet is only placed in the kernel memory with the help of DMA Engine of the NIC. so to do it CPU is not required and a sk_buff structure is allocated for this packet. & this sk_buff’s pionter is place in the CPU backlog.
2-> soft iterrupt in this case there is a soft interrupt is generated which is responsible for removing the packet from cpu backlog & process it for upper layer in the network stack.
& for your question uses of 2 cpu core there is used only one cpu core because in NAPI
if another packet comes during the processing of the previous one then there is no interrupt generated but only this packet is placed in the linux-kernel with the help of DMA. & the running interrupt just pics the packet & continue its processing.