DPDK FAQ

This document contains some Frequently Asked Questions that arise when working with DPDK.

• 1. What does “EAL: map_all_hugepages(): open failed: Permission denied Cannot init memory” mean?
• 2. If I want to change the number of TLB Hugepages allocated, how do I remove the original pages allocated?
• 3. If I execute “l2fwd -c f -m 64 -n 3 – -p 3”, I get the following output, indicating that there are no socket 0 hugepages to allocate the mbuf and ring structures to?
• 4. I am running a 32-bit DPDK application on a NUMA system, and sometimes the application initializes fine but cannot allocate memory. Why is that happening?
• 5. On application startup, there is a lot of EAL information printed. Is there any way to reduce this?
• 6. How can I tune my network application to achieve lower latency?
• 7. Without NUMA enabled, my network throughput is low, why?
• 8. I am getting errors about not being able to open files. Why?
• 9. VF driver for IXGBE devices cannot be initialized
• 10. Is it safe to add an entry to the hash table while running?
• 11. What is the purpose of setting iommu=pt?
• 12. When trying to send packets from an application to itself, meaning smac==dmac, using Intel(R) 82599 VF packets are lost.
• 13. Can I split packet RX to use DPDK and have an application’s higher order functions continue using Linux pthread?
• 14. Is it possible to exchange data between DPDK processes and regular userspace processes via some shared memory or IPC mechanism?
• 15. Can the multiple queues in Intel(R) I350 be used with DPDK?
• 16. How can hugepage-backed memory be shared among multiple processes?