From: Ferruh Yigit <ferruh.yigit@amd.com>
To: Damodharam Ammepalli <damodharam.ammepalli@broadcom.com>,
Thomas Monjalon <thomas@monjalon.net>
Cc: Dengdui Huang <huangdengdui@huawei.com>,
dev@dpdk.org, aman.deep.singh@intel.com, yuying.zhang@intel.com,
andrew.rybchenko@oktetlabs.ru, liuyonglong@huawei.com,
fengchengwen@huawei.com, haijie1@huawei.com,
lihuisong@huawei.com
Subject: Re: [PATCH 0/3] support setting lanes
Date: Wed, 20 Mar 2024 12:31:28 +0000 [thread overview]
Message-ID: <aba73288-9410-407a-a9f7-0e58bf5f582a@amd.com> (raw)
In-Reply-To: <CAKSYD4wWYLMiFYXV=ZcGju44UJ_0C_pWT4_rOteri4-t=Wb24A@mail.gmail.com>
On 3/18/2024 9:26 PM, Damodharam Ammepalli wrote:
> On Mon, Mar 18, 2024 at 7:56 AM Thomas Monjalon <thomas@monjalon.net> wrote:
>>
>> 12/03/2024 08:52, Dengdui Huang:
>>> Some speeds can be achieved with different number of lanes. For example,
>>> 100Gbps can be achieved using two lanes of 50Gbps or four lanes of 25Gbps.
>>> When use different lanes, the port cannot be up.
>>
>> I'm not sure what you are referring to.
>> I suppose it is not PCI lanes.
>> Please could you link to an explanation of how a port is split in lanes?
>> Which hardware does this?
>>
>>
>>
> This is a snapshot of 100Gb that the latest BCM576xx supports.
> 100Gb (NRZ: 25G per lane, 4 lanes) link speed
> 100Gb (PAM4-56: 50G per lane, 2 lanes) link speed
> 100Gb (PAM4-112: 100G per lane, 1 lane) link speed
>
> Let the user feed in lanes=< integer value> and the NIC driver decides
> the matching combination speed x lanes that works. In future if a new speed
> is implemented with more than 8 lanes, there wouldn't be a need
> to touch this speed command. Using separate lane command would
> be a better alternative to support already shipped products and only new
> drivers would consider this lanes configuration, if applicable.
>
As far as I understand, lane is related to the physical layer of the
NIC, there are multiple copies of transmitter, receiver, modulator HW
block and each set called as a 'lane' and multiple lanes work together
to achieve desired speed. (please correct me if this is wrong).
Why not just configuring the speed is not enough? Why user needs to know
the detail and configuration of the lanes?
Will it work if driver/device configure the "speed x lane" internally
for the requested speed?
Is there a benefit to force specific lane count for a specific speed
(like power optimization, just a wild guess)?
And +1 for auto-negotiation if possible.
next prev parent reply other threads:[~2024-03-20 12:31 UTC|newest]
Thread overview: 52+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-03-12 7:52 Dengdui Huang
2024-03-12 7:52 ` [PATCH 1/3] ethdev: " Dengdui Huang
2024-03-19 3:02 ` Stephen Hemminger
2024-03-20 1:16 ` huangdengdui
2024-03-12 7:52 ` [PATCH 2/3] net/hns3: " Dengdui Huang
2024-03-12 7:52 ` [PATCH 3/3] app/testpmd: " Dengdui Huang
2024-03-15 21:47 ` Damodharam Ammepalli
2024-03-19 2:38 ` huangdengdui
2024-03-22 7:09 ` [PATCH v2 0/6] " Dengdui Huang
2024-03-22 7:09 ` [PATCH v2 1/6] ethdev: " Dengdui Huang
2024-03-22 13:58 ` Thomas Monjalon
2024-03-22 15:15 ` Ajit Khaparde
2024-03-22 17:32 ` Tyler Retzlaff
2024-03-22 22:30 ` Damodharam Ammepalli
2024-03-25 6:24 ` huangdengdui
2024-03-25 9:30 ` Thomas Monjalon
2024-03-25 21:14 ` Damodharam Ammepalli
2024-03-26 1:42 ` lihuisong (C)
2024-03-26 3:45 ` Ajit Khaparde
2024-03-26 10:30 ` Thomas Monjalon
2024-03-26 11:15 ` lihuisong (C)
2024-03-26 13:47 ` Ajit Khaparde
2024-03-26 18:11 ` Ajit Khaparde
2024-03-26 18:21 ` Damodharam Ammepalli
2024-03-30 11:38 ` huangdengdui
2024-04-01 20:07 ` Thomas Monjalon
2024-04-01 22:29 ` Damodharam Ammepalli
2024-04-02 8:37 ` huangdengdui
2024-04-02 15:28 ` Stephen Hemminger
2024-04-04 13:45 ` Ferruh Yigit
2024-03-29 3:25 ` lihuisong (C)
2024-03-22 7:09 ` [PATCH v2 2/6] test: updated UT for " Dengdui Huang
2024-03-22 7:09 ` [PATCH v2 3/6] ethdev: add function to parse link mode info Dengdui Huang
2024-03-22 7:09 ` [PATCH v2 4/6] net/hns3: use parse link mode info function Dengdui Huang
2024-03-22 7:09 ` [PATCH v2 5/6] net/hns3: support setting lanes Dengdui Huang
2024-03-22 7:09 ` [PATCH v2 6/6] app/testpmd: " Dengdui Huang
2024-04-04 13:58 ` [PATCH v2 0/6] " Ferruh Yigit
2024-05-16 12:48 ` huangdengdui
2024-03-18 14:56 ` [PATCH 0/3] " Thomas Monjalon
2024-03-18 21:26 ` Damodharam Ammepalli
2024-03-18 21:42 ` Stephen Hemminger
2024-03-18 22:55 ` Ajit Khaparde
2024-03-20 11:41 ` Thomas Monjalon
2024-03-20 12:31 ` Ferruh Yigit [this message]
2024-03-21 2:02 ` huangdengdui
2024-03-21 8:28 ` Thomas Monjalon
2024-03-22 2:28 ` huangdengdui
2024-03-22 4:38 ` Jerin Jacob
2024-03-22 5:25 ` Ajit Khaparde
2024-03-22 5:51 ` Jerin Jacob
2024-03-22 13:51 ` Thomas Monjalon
2024-03-25 14:04 ` Jerin Jacob
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