Re: [PATCH RESEND net-next v14 3/5] ethtool: provide customized dim profile management

[Simon Horman <horms@kernel.org>]

On Tue, Jun 18, 2024 at 10:56:42AM +0800, Heng Qi wrote:
> The NetDIM library, currently leveraged by an array of NICs, delivers
> excellent acceleration benefits. Nevertheless, NICs vary significantly
> in their dim profile list prerequisites.
> 
> Specifically, virtio-net backends may present diverse sw or hw device
> implementation, making a one-size-fits-all parameter list impractical.
> On Alibaba Cloud, the virtio DPU's performance under the default DIM
> profile falls short of expectations, partly due to a mismatch in
> parameter configuration.
> 
> I also noticed that ice/idpf/ena and other NICs have customized
> profilelist or placed some restrictions on dim capabilities.
> 
> Motivated by this, I tried adding new params for "ethtool -C" that provides
> a per-device control to modify and access a device's interrupt parameters.
> 
> Usage
> ========
> The target NIC is named ethx.
> 
> Assume that ethx only declares support for rx profile setting
> (with DIM_PROFILE_RX flag set in profile_flags) and supports modification
> of usec and pkt fields.
> 
> 1. Query the currently customized list of the device
> 
> $ ethtool -c ethx
> ...
> rx-profile:
> {.usec =   1, .pkts = 256, .comps = n/a,},
> {.usec =   8, .pkts = 256, .comps = n/a,},
> {.usec =  64, .pkts = 256, .comps = n/a,},
> {.usec = 128, .pkts = 256, .comps = n/a,},
> {.usec = 256, .pkts = 256, .comps = n/a,}
> tx-profile:   n/a
> 
> 2. Tune
> $ ethtool -C ethx rx-profile 1,1,n_2,n,n_3,3,n_4,4,n_n,5,n
> "n" means do not modify this field.
> $ ethtool -c ethx
> ...
> rx-profile:
> {.usec =   1, .pkts =   1, .comps = n/a,},
> {.usec =   2, .pkts = 256, .comps = n/a,},
> {.usec =   3, .pkts =   3, .comps = n/a,},
> {.usec =   4, .pkts =   4, .comps = n/a,},
> {.usec = 256, .pkts =   5, .comps = n/a,}
> tx-profile:   n/a
> 
> 3. Hint
> If the device does not support some type of customized dim profiles,
> the corresponding "n/a" will display.
> 
> If the "n/a" field is being modified, -EOPNOTSUPP will be reported.
> 
> Signed-off-by: Heng Qi <hengqi@linux.alibaba.com>

Reviewed-by: Simon Horman <horms@kernel.org>