Re: core performance

[Nishant Verma <vnish11@gmail.com>]

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Also make sure all core you are using are physical core not the logical
core.
Secondly, check your core isolation options and apply them accordingly.


.

Regards,
Nishant Verma


On Mon, Sep 23, 2024 at 6:04 PM Wisam Jaddo <wisamm@nvidia.com> wrote:

> Hello Amit,
>
> > -----Original Message-----
> > From: amit sehas <cun23@yahoo.com>
> > Sent: Monday, September 23, 2024 11:57 PM
> > To: users@dpdk.org
> > Subject: core performance
> >
> > We are seeing different dpdk threads (launched
> via rte_eal_remote_launch()),
> > demonstrate very different performance.
> >
> >
> >
> > After placing counters all over the code, we realize that some threads
> are
> > uniformly slow, in other words there is no application level issue that
> is
> > throttling one thread over the other. We come to the conculsion that
> either
> > the Cores on which they are running are not at the same frequency which
> > seems doubtful or the threads are not getting a chance to execute on the
> cores
> > uniformly.
> >
> >
> >
> > It seems that isolcpus has been deprecated in recent versions of linux.
> >
> >
> >
> > What is the recommended approach to prevent the kernel from utilizing
> some
> > CPU threads, for anything other than the threads that are launched on
> them.
>
> If you are wishing to run each thread on separate core, try to use
> rte_eal_mp_remote_launch()
> instead of rte_eal_remote_launch(), make sure that your CPU is isolated,
> and you are passing correct
> Cores that were isolated to your app using -c, -l.
>
>
> >
> >
> >
> > Is there some API in dpdk which also helps us determine which CPU core
> the
> > thread is pinned to?
> >
> > I did not find any code in dpdk which actually performed pinning of a
> thread to
> > a CPU core.
> >
> >
> >
> > In our case it is more or less certain that the different threads are
> simply not
> > getting the same CPU core time, as a result some are demonstrating higher
> > throughput than the others ...
> >
> >
> >
> > how do we fix this?
>
> BRs,
> Wisam Jaddo
>

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