netdev - Re: mlx5 broken affinity

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Message-ID: <573060a9-19a7-9133-ef52-fa947088dabb@fb.com>
Date:   Wed, 1 Nov 2017 19:02:58 -0400
From:   Jes Sorensen <jsorensen@...com>
To:     Saeed Mahameed <saeedm@....mellanox.co.il>,
        Tariq Toukan <tariqt@...lanox.com>
CC:     Sagi Grimberg <sagi@...mberg.me>,
        Networking <netdev@...r.kernel.org>,
        Leon Romanovsky <leonro@...lanox.com>,
        Saeed Mahameed <saeedm@...lanox.com>,
        Kernel Team <kernel-team@...com>,
        Christoph Hellwig <hch@....de>
Subject: Re: mlx5 broken affinity

On 11/01/2017 06:41 PM, Saeed Mahameed wrote:
> On Wed, Nov 1, 2017 at 11:20 AM, Jes Sorensen <jsorensen@...com> wrote:
>> On 11/01/2017 01:21 PM, Sagi Grimberg wrote:
>> I am all in favor of making the automatic setup better, but assuming an
>> automatic setup is always right seems problematic. There could be
>> workloads where you may want to assign affinity explicitly.
>>
>> Jes
> 
> I vaguely remember Nacking Sagi's patch as we knew it would break
> mlx5e netdev affinity assumptions.
> Anyway we already submitted the mlx5e patch that removed such assumption
> 
> https://urldefense.proofpoint.com/v2/url?u=https-3A__patchwork.ozlabs.org_patch_809196_&d=DwIBaQ&c=5VD0RTtNlTh3ycd41b3MUw&r=zRrmoWoylV2tnG53v9ZA2w&m=Z6xtsiQVL8xhTauY_DrOWYDhci-D49TqNKLWV_HK5Ug&s=pkxagNCZzy5-ZzMRTxIQ5pDfFq8WOSRdSx5zeQpQdBI&e= ("net/mlx5e: Distribute RSS
> table among all RX rings")
> Jes please confirm you have it.
> 
> And I agree here that user should be able to read
> /proc/irq/x/smp_affinity and even modify it if required.

Hi Saeed,

I can confirm I have that patch - the problem is also present in Linus'
current tree.

I can read smp_affinity, but I cannot write to it.

Cheers,
Jes