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Date: Sun, 16 Feb 2014 11:02:41 -0800
From: Stephen Hemminger <stephen@networkplumber.org>
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Cc: "dev@dpdk.org" <dev@dpdk.org>
Subject: Re: [dpdk-dev] Is it possible to have dpdk running with no
 dependency on a nic ?
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On Fri, 14 Feb 2014 15:11:29 -0500
Ymo Lists <ymolists@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=AE D=
PDK
> 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."
>=20
> 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 witho=
ut
any perceivable gain in performance. The larger code causes more cache miss=
es
which actually hurt performance.  Also using GCC link time optimization hel=
ps
to reduce any need for inlining larger code bits.