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From: Stephen Hemminger <stephen@networkplumber.org>
To: Ferruh Yigit <ferruh.yigit@intel.com>
Cc: Ciara Loftus <ciara.loftus@intel.com>, <dev@dpdk.org>,
	<anatoly.burakov@intel.com>
Subject: Re: [PATCH v3] net/af_xdp: re-enable secondary process support
Date: Tue, 8 Feb 2022 10:42:01 -0800	[thread overview]
Message-ID: <20220208104201.6afef73b@hermes.local> (raw)
In-Reply-To: <6e2bbf05-102f-f84d-cc51-3663dc270015@intel.com>

On Tue, 8 Feb 2022 18:00:27 +0000
Ferruh Yigit <ferruh.yigit@intel.com> wrote:

> On 2/8/2022 5:45 PM, Stephen Hemminger wrote:
> > On Tue,  8 Feb 2022 13:48:00 +0000
> > Ciara Loftus <ciara.loftus@intel.com> wrote:
> >   
> >> +- **Secondary Processes**
> >> +
> >> +  Rx and Tx are not supported for secondary processes due to the single-producer
> >> +  single-consumer nature of the AF_XDP rings. However other operations including
> >> +  statistics retrieval are permitted.
> >> +  The maximum number of queues permitted for PMDs operating in this model is 8
> >> +  as this is the maximum number of fds that can be sent through the IPC APIs as
> >> +  defined by RTE_MP_MAX_FD_NUM.
> >> +  
> > 
> > This seems like a restriction that is true for most devices in DPDK.
> > Most other devices also have restriction that on queues;
> > the hardware descriptor ring can only be used by one thread at a time.
> > Is this different with AF_XDP?  
> 
> I asked the same on v2 :) and Ciara explained the reason, it is on v2 discussion thread.

The wording of the message is what confused me.
It would be better to change:
    due to the single-producer single-consumer nature of the AF_XDP rings
to
    due to memory mapping of the AF_XDP rings being assigned by the kernel
    in the primary process only.

  reply	other threads:[~2022-02-08 18:42 UTC|newest]

Thread overview: 36+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-12-10 15:32 [RFC PATCH] net/af_xdp: reenable " Ciara Loftus
2021-12-11 21:49 ` Stephen Hemminger
2022-01-12  7:54 ` [PATCH] net/af_xdp: re-enable " Ciara Loftus
2022-02-04 12:54   ` [PATCH v2] " Ciara Loftus
2022-02-04 14:18     ` Ferruh Yigit
2022-02-07  7:49       ` Loftus, Ciara
2022-02-07 10:27         ` Ferruh Yigit
2022-02-07 11:39           ` Loftus, Ciara
2022-02-08 10:58             ` Ferruh Yigit
2022-02-08 13:48     ` [PATCH v3] " Ciara Loftus
2022-02-08 17:45       ` Stephen Hemminger
2022-02-08 18:00         ` Ferruh Yigit
2022-02-08 18:42           ` Stephen Hemminger [this message]
2022-02-08 18:56             ` Ferruh Yigit
2022-02-09  7:41               ` Loftus, Ciara
2022-02-09  9:48       ` [PATCH v4] " Ciara Loftus
2022-02-09 15:29         ` Stephen Hemminger
2022-02-11 13:32           ` Ferruh Yigit
2022-02-09 17:55         ` Ferruh Yigit
2022-02-10 15:08           ` Ferruh Yigit
2022-02-10 15:19         ` Ferruh Yigit
2022-02-10 15:40           ` Loftus, Ciara
2022-02-10 16:06             ` Ferruh Yigit
2022-02-10 17:47               ` Loftus, Ciara
2022-02-10 20:12                 ` Ferruh Yigit
2022-02-11  7:28                   ` Loftus, Ciara
2022-02-11  9:26                     ` Loftus, Ciara
2022-02-11 12:29                       ` Ferruh Yigit
2022-02-11 13:01                         ` Loftus, Ciara
2022-02-11 13:07                           ` Ferruh Yigit
2022-02-11 15:32                             ` Loftus, Ciara
2022-02-16 11:23                               ` Loftus, Ciara
2022-02-11 11:31                     ` Ferruh Yigit
2022-02-17 12:44         ` David Marchand
2022-02-17 12:47           ` Ferruh Yigit
2022-02-17 12:53             ` David Marchand

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