netdev - Re: [PATCH net 3/3] bnxt_en: Update MRU and RSS table of RSS contexts on queue reset

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Message-ID: <ff26ec09-6c00-4aff-9a18-25bcc4a3a5a7@davidwei.uk>
Date: Tue, 27 May 2025 16:37:56 +0100
From: David Wei <dw@...idwei.uk>
To: Jakub Kicinski <kuba@...nel.org>
Cc: Michael Chan <michael.chan@...adcom.com>, davem@...emloft.net,
 netdev@...r.kernel.org, edumazet@...gle.com, pabeni@...hat.com,
 andrew+netdev@...n.ch, pavan.chebbi@...adcom.com,
 andrew.gospodarek@...adcom.com
Subject: Re: [PATCH net 3/3] bnxt_en: Update MRU and RSS table of RSS contexts
 on queue reset

On 2025-05-22 16:26, Jakub Kicinski wrote:
> On Thu, 22 May 2025 12:01:34 +0100 David Wei wrote:
>> On 5/20/25 19:29, Michael Chan wrote:
>>> On Tue, May 20, 2025 at 7:17 PM Jakub Kicinski <kuba@...nel.org> wrote:
>>>> "reliable" is a bit of a big word that some people would reserve
>>>> for code which is production tested or at the very least very
>>>> heavily validated.
>>>
>>> FWIW, queue_mgmt_ops was heavily tested by Somnath under heavy traffic
>>> conditions.  Obviously RSS contexts were not included during testing
>>> and this problem was missed.
>>
>> IIRC from the initial testing w/ Somnath even though the VNICs are reset
>> the traffic on unrelated queues are unaffected.
> 
> How did you check that? IIUC the device does not currently report
> packet loss due to MRU clamp (!?!)

Only from iperf3. On the server side while it is running, resetting
queues do not affect it. Didn't check for packet drops, though...

> 
>> If we ensure that is the cse with this patchset, would that resolve
>> your concerns Jakub?
> 
> For ZC we expect the queues to be taken out of the main context.
> IIUC it'd be a significant improvement over the status quo if
> we could check which contexts the queue is in (incl. context 0)
> and only clamp MRU on those.

Got it, thanks. Michael, is that something the FW is able to handle
without affecting the queue reset behaviour?