[dpdk-dev] DPDK testpmd, Virtual Disk IO limitation
Bruce Richardson
bruce.richardson at intel.com
Wed Mar 25 18:32:48 CET 2015
On Thu, Mar 26, 2015 at 12:20:42AM +0800, Cheng Kevin wrote:
> Mr. Bruce Richardson
>
> Yes, you are right. This really bother me.
>
> Is there any way to get rid of system call? Maybe some DPDK threading API?
> Maybe i should use a extra nic card for posting the data out through
> internet, instead of writing on the disk - ex. fwrite.
>
> Or you have some better advises??
>
> Thanks
> Kevin
>
Hi Kevin,
what is your end-goal that you are trying to get to?
/Bruce
>
> 2015-03-25 23:01 GMT+08:00 Bruce Richardson <bruce.richardson at intel.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
> >
More information about the dev
mailing list