netdev - Re: [PATCH] mlx4_ib: Increase the timeout for CM cache

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Date:   Wed, 6 Feb 2019 19:16:45 +0100
From:   Håkon Bugge <haakon.bugge@...cle.com>
To:     jackm <jackm@....mellanox.co.il>
Cc:     Jason Gunthorpe <jgg@...pe.ca>
Subject: Re: [PATCH] mlx4_ib: Increase the timeout for CM cache



> On 6 Feb 2019, at 19:02, jackm <jackm@....mellanox.co.il> wrote:
> 
> On Wed, 6 Feb 2019 16:40:14 +0100
> Håkon Bugge <haakon.bugge@...cle.com> wrote:
> 
>> Jack,
>> 
>> A major contributor to the long processing time in the PF driver
>> proxying QP1 packets is:
>> 
>> create_pv_resources
>>   -> ib_create_cq(ctx->ib_dev, mlx4_ib_tunnel_comp_handler,  
>>                               NULL, ctx, cq_size, 0);
>> 
>> That is, comp_vector is zero.
>> 
>> Due to commit 6ba1eb776461 ("IB/mlx4: Scatter CQs to different EQs"),
>> the zero comp_vector has the intent of let the mlx4_core driver
>> select the least used vector.
>> 
>> But, in mlx4_ib_create_cq(), we have:
>> 
>>        pr_info("eq_table: %p\n", dev->eq_table);
>>        if (dev->eq_table) {
>> 		vector = dev->eq_table[mlx4_choose_vector(dev->dev,
>> vector, ibdev->num_comp_vectors)];
>>        }
>> 
>>        cq->vector = vector;
>> 
>> and dev->eq_table is NULL, so all the CQs for the proxy QPs get
>> comp_vector zero.
>> 
>> I have to make some reservations, as this analysis is based on uek4,
>> but I think the code here is equal upstream, but need to double check.
>> 
>> 
>> Thxs, Håkon
>> 
> Hi Hakon and Jason,
> I was ill today (bad cold, took antihistamines all day, which knocked
> me out).
> I'll get to this tomorrow.

No problem Jack. I actually see that our uek4 is different in mlx4_ib_alloc_eqs(), and that may well be the root cause here.

Hence, moved the MLs to Bcc, and get back to you tomorrow.


Thxs, Håkon