From: "Дмитрий Степанов" <stepanov.dmit@gmail.com>
To: Dmitry Kozlyuk <dkozlyuk@nvidia.com>
Cc: users@dpdk.org
Subject: Re: Mellanox performance degradation with more than 12 lcores
Date: Fri, 18 Feb 2022 19:14:08 +0300 [thread overview]
Message-ID: <CA+-SuJ1w5NKSW=CsdVRSB9_+C5Kk48FqAAsOKdOXbNjWNt_+wA@mail.gmail.com> (raw)
In-Reply-To: <20220218133952.3084134-1-dkozlyuk@nvidia.com>
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Thanks for the clarification!
I was able to get 148Mpps with 12 lcores after some BIOS tunings.
Looks like due to these HW limitations I have to use ring buffer as you
suggested to support more than 32 lcores!
пт, 18 февр. 2022 г. в 16:40, Dmitry Kozlyuk <dkozlyuk@nvidia.com>:
> Hi,
>
> > With more than 12 lcores overall receive performance reduces.
> > With 16-32 lcores I get 100-110 Mpps,
>
> It is more about the number of queues than the number of cores:
> 12 queues are the threshold when Multi-Packet Receive Queue (MPRQ)
> is automatically enabled in mlx5 PMD.
> Try increasing --rxd and check out mprq_en device argument.
> Please see mlx5 PMD user guide for details about MPRQ.
> You should be able to get full 148 Mpps with your HW.
>
> > and I get a significant performance fall with 33 lcores - 84Mpps.
> > With 63 cores I get even 35Mpps overall receive performance.
> >
> > Are there any limitations on the total number of receive queues (total
> > lcores) that can handle a single port on a given NIC?
>
> This is a hardware limitation.
> The limit on the number of queues you can create is very high (16M),
> but performance can perfectly scale only up to 32 queues
> at high packet rates (as opposed to bit rates).
> Using more queues can even degrade it, just as you observe.
> One way to overcome this (not specific to mlx5)
> is to use a ring buffer for incoming packets,
> from which any number of processing cores can take packets.
>
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prev parent reply other threads:[~2022-02-21 17:33 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-02-18 7:32 Дмитрий Степанов
2022-02-18 13:30 ` Asaf Penso
2022-02-18 13:49 ` Дмитрий Степанов
2022-02-18 13:39 ` Dmitry Kozlyuk
2022-02-18 16:14 ` Дмитрий Степанов [this message]
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