Regarding latency of Netmap i/o

[Luigi Rizzo]

On Mon, Jul 2, 2018 at 1:34 AM, Suneet Singh <er.suneetsingh at gmail.com> wrote:
> Dear Professor,
>
> I am Suneet from India. I am a PhD student in Unicamp, Campinas, Brazil. I
> am testing latency of MACSAD P4 software switch. I found that latency using
> netmap i/o is higher than using socket_mmap i/o while in case of dpdk,
> latency is very low.

please quantify the latency the type of experiment you run, the system's
configuration and the latency figures that you are seeing because 'higher'
and 'very low' mean nothing without context.

Batching is almost never a reason for significantly higher latency
unless it is misused.

Typically there are mistakes in setting up the experiment that
cause higher latency than expected

cheers
luigi

>
> As I read the research papers related to netmap, I found that it may be the
> reason of high latency in case of netmap compare to socket_mmap due to batch
> process.
>
> However, I am not sure why latency of my switch is higher using netmap
> compare to sockte mmap. I am requesting you to please let me know the
> performance of netmap interms of latency (end-to-end) compare to
> socket_mmap.
>
> Thank you so much for your precious time.
>
> " Man needs his difficulties because they are necessary to enjoy success."
>
> Kind Regards
> Suneet Kumar Singh
>
> https://www.researchgate.net/profile/Suneet_Singh7



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