From: Stephen Hemminger <stephen@networkplumber.org>
To: Ymo Lists <ymolists@gmail.com>
Cc: "dev@dpdk.org" <dev@dpdk.org>
Subject: Re: [dpdk-dev] Is it possible to have dpdk running with no dependency on a nic ?
Date: Sun, 16 Feb 2014 11:02:41 -0800 [thread overview]
Message-ID: <20140216110241.0e789750@nehalam.linuxnetplumber.net> (raw)
In-Reply-To: <CACSP18QdpFb71x0JymmDuicz7ft68U6cbcNVC=i47yprWp4FWQ@mail.gmail.com>
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® 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.
next prev parent reply other threads:[~2014-02-16 19:01 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-02-12 18:21 Ymo Lists
2014-02-13 20:19 ` Ymo Lists
2014-02-14 8:42 ` Vivek Soni
2014-02-14 17:20 ` Ymo Lists
2014-02-14 18:20 ` Jayakumar, Muthurajan
2014-02-14 20:11 ` Ymo Lists
2014-02-16 19:02 ` Stephen Hemminger [this message]
2014-02-17 12:49 ` jigsaw
2014-02-17 16:41 ` Stephen Hemminger
2014-02-17 17:52 ` Venkatesan, Venky
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