From: Bruce Richardson <bruce.richardson@intel.com>
To: Cheng Kevin <k5896246@gmail.com>
Cc: dev@dpdk.org
Subject: Re: [dpdk-dev] DPDK testpmd, Virtual Disk IO limitation
Date: Wed, 25 Mar 2015 15:01:57 +0000 [thread overview]
Message-ID: <20150325150156.GA5620@bricha3-MOBL3> (raw)
In-Reply-To: <CACnuE8Fynh9PNekD5jLamTfnzp1E-9r11MwnLqP_u+n8wdE22Q@mail.gmail.com>
On Wed, Mar 25, 2015 at 10:06:48PM +0800, Cheng Kevin wrote:
> Hi all,
>
> I am a beginner of DPDK. Recently, i am interest in DPDK vHost app -
> testpmd.
>
> And i have been tracing on testpmd.c and iofwd.c for a while.
>
> Also add some code inside iofwd.c for storing the payload of packets.
>
> Everything goes fine, and the performance is great as expected.
>
> But when i use fwrite to store the payload into a file,
>
> the performance decrease from 800mbps to 3mbps (input stream is 1 Gbps).
>
> Is is caused by the limitation of Virtual Disk IO? How can i solve it?
>
> I have tried to search the answer, some people say "pthread" might solve
> the problem.
>
> Can someone give me some hint, i really appreciate for your help.
>
>
> Best Regard,
>
> Kevin Cheng
Two general issues you will hit writing to disk:
1) IO, including disk IO, is slow
2) System calls are slow.
You are probably hitting both bottlenecks.
/Bruce
next prev parent reply other threads:[~2015-03-25 15:02 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-03-25 14:06 Cheng Kevin
2015-03-25 15:01 ` Bruce Richardson [this message]
2015-03-25 16:20 ` Cheng Kevin
2015-03-25 17:32 ` Bruce Richardson
2015-03-25 23:47 ` Cheng Kevin
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