[dpdk-dev] Is it possible to have dpdk running with no dependency on a nic ?

Stephen Hemminger stephen at networkplumber.org
Sun Feb 16 20:02:41 CET 2014

On Fri, 14 Feb 2014 15:11:29 -0500
Ymo Lists <ymolists at gmail.com> wrote:

> "Enqueuing and dequeuing items from an rte_ring using the rings-based PMD
> may be slower than using the native rings API. This is because Intel® DPDK
> Ethernet drivers make use of function pointers to call the appropriate
> enqueue or dequeue functions, while the rte_ring specific functions are
> direct function calls in the code and are often inlined by the compiler."
> Is that statement correct ? I would imagine that inlined code would be be
> faster than using function pointers ?

Actually, the Intel DPDK has a bad case of inlineitis. The code for ring's
and other parts use inline on largish functions which bloats the code without
any perceivable gain in performance. The larger code causes more cache misses
which actually hurt performance.  Also using GCC link time optimization helps
to reduce any need for inlining larger code bits.

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