netdev - Re: [PATCH V7 net-next 02/11] net/mlx5: Implement cqe_compress

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Message-ID: <ec51df17-260e-4ec9-a44a-9f0c3d3a2766@gmail.com>
Date: Fri, 17 Oct 2025 17:51:25 -0400
From: Daniel Zahka <daniel.zahka@...il.com>
To: Saeed Mahameed <saeed@...nel.org>, "David S. Miller"
 <davem@...emloft.net>, Jakub Kicinski <kuba@...nel.org>,
 Paolo Abeni <pabeni@...hat.com>, Eric Dumazet <edumazet@...gle.com>
Cc: Saeed Mahameed <saeedm@...dia.com>, netdev@...r.kernel.org,
 Tariq Toukan <tariqt@...dia.com>, Gal Pressman <gal@...dia.com>,
 Leon Romanovsky <leonro@...dia.com>, Jiri Pirko <jiri@...dia.com>,
 Jacob Keller <jacob.e.keller@...el.com>, Simon Horman <horms@...nel.org>
Subject: Re: [PATCH V7 net-next 02/11] net/mlx5: Implement cqe_compress_type
 via devlink params

On 9/6/25 9:29 PM, Saeed Mahameed wrote:
> From: Saeed Mahameed <saeedm@...dia.com>
>
> Selects which algorithm should be used by the NIC in order to decide rate of
> CQE compression dependeng on PCIe bus conditions.
>
> Supported values:
>
> 1) balanced, merges fewer CQEs, resulting in a moderate compression ratio
>     but maintaining a balance between bandwidth savings and performance
> 2) aggressive, merges more CQEs into a single entry, achieving a higher
>     compression rate and maximizing performance, particularly under high
>     traffic loads.
>

Hello,

I'm facing some issues when trying to use the devlink param introduced 
in this patch. I have a multihost system with two hosts per CX7.

My NIC is:
$ lshw -C net
   *-network
        description: Ethernet interface
        product: MT2910 Family [ConnectX-7]
        vendor: Mellanox Technologies

My fw version is: 28.43.1014

To reproduce the problem I simply read the current cqe_compress_type 
setting and then change it:

$ devlink dev param show pci/0000:56:00.0 name cqe_compress_type
pci/0000:56:00.0:
   name cqe_compress_type type driver-specific
     values:
       cmode permanent value balanced

$ devlink dev param set pci/0000:56:00.0 name cqe_compress_type value 
"aggressive" cmode permanent
kernel answers: Connection timed out

from dmesg:
[  257.111349] mlx5_core 0000:56:00.0: 
wait_func_handle_exec_timeout:1159:(pid 72061): cmd[0]: 
ACCESS_REG(0x805) No done completion
[  257.137072] mlx5_core 0000:56:00.0: wait_func:1189:(pid 72061): 
ACCESS_REG(0x805) timeout. Will cause a leak of a command resource
[  270.871521] mlx5_core 0000:56:00.0: mlx5_cmd_comp_handler:1709:(pid 
0): Command completion arrived after timeout (entry idx = 0).

subsequent attempts to use mstfwreset hang:

$ ./mstfwreset -y -d 56:00.0 reset
-E- Failed to send Register MFRL: Timed out trying to take the ICMD 
semaphore (520).

I can toggle the parameter ok using the mstconfig binary built from the 
mstflint github repo.

Let me know if I can provide any more information.

Daniel