Date:   Tue, 21 Dec 2021 15:34:58 -0800
From:   Stephen Hemminger <stephen@networkplumber.org>
To:     Mike Ximing Chen <mike.ximing.chen@intel.com>
Cc:     linux-kernel@vger.kernel.org, arnd@arndb.de,
        gregkh@linuxfoundation.org, dan.j.williams@intel.com,
        pierre-louis.bossart@linux.intel.com, netdev@vger.kernel.org,
        davem@davemloft.net, kuba@kernel.org
Subject: Re: [RFC PATCH v12 17/17] dlb: add basic sysfs interfaces
Message-ID: <20211221153458.51710479@hermes.local>
In-Reply-To: <20211221065047.290182-18-mike.ximing.chen@intel.com>
References: <20211221065047.290182-1-mike.ximing.chen@intel.com>
        <20211221065047.290182-18-mike.ximing.chen@intel.com>
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On Tue, 21 Dec 2021 00:50:47 -0600
Mike Ximing Chen <mike.ximing.chen@intel.com> wrote:

> The dlb sysfs interfaces include files for reading the total and
> available device resources, and reading the device ID and version. The
> interfaces are used for device level configurations and resource
> inquiries.
> 
> Signed-off-by: Mike Ximing Chen <mike.ximing.chen@intel.com>
> ---
>  Documentation/ABI/testing/sysfs-driver-dlb | 116 ++++++++++++
>  drivers/misc/dlb/dlb_args.h                |  34 ++++
>  drivers/misc/dlb/dlb_main.c                |   5 +
>  drivers/misc/dlb/dlb_main.h                |   3 +
>  drivers/misc/dlb/dlb_pf_ops.c              | 195 +++++++++++++++++++++
>  drivers/misc/dlb/dlb_resource.c            |  50 ++++++
>  6 files changed, 403 insertions(+)
>  create mode 100644 Documentation/ABI/testing/sysfs-driver-dlb
> 
> diff --git a/Documentation/ABI/testing/sysfs-driver-dlb b/Documentation/ABI/testing/sysfs-driver-dlb
> new file mode 100644
> index 000000000000..bf09ef6f8a3a
> --- /dev/null
> +++ b/Documentation/ABI/testing/sysfs-driver-dlb
> @@ -0,0 +1,116 @@
> +What:		/sys/bus/pci/devices/.../total_resources/num_atomic_inflights
> +What:		/sys/bus/pci/devices/.../total_resources/num_dir_credits
> +What:		/sys/bus/pci/devices/.../total_resources/num_dir_ports
> +What:		/sys/bus/pci/devices/.../total_resources/num_hist_list_entries
> +What:		/sys/bus/pci/devices/.../total_resources/num_ldb_credits
> +What:		/sys/bus/pci/devices/.../total_resources/num_ldb_ports
> +What:		/sys/bus/pci/devices/.../total_resources/num_cos0_ldb_ports
> +What:		/sys/bus/pci/devices/.../total_resources/num_cos1_ldb_ports
> +What:		/sys/bus/pci/devices/.../total_resources/num_cos2_ldb_ports
> +What:		/sys/bus/pci/devices/.../total_resources/num_cos3_ldb_ports
> +What:		/sys/bus/pci/devices/.../total_resources/num_ldb_queues
> +What:		/sys/bus/pci/devices/.../total_resources/num_sched_domains
> +Date:		Oct 15, 2021
> +KernelVersion:	5.15
> +Contact:	mike.ximing.chen@intel.com
> +Description:
> +		The total_resources subdirectory contains read-only files that
> +		indicate the total number of resources in the device.
> +
> +		num_atomic_inflights:  Total number of atomic inflights in the
> +				       device. Atomic inflights refers to the
> +				       on-device storage used by the atomic
> +				       scheduler.
> +
> +		num_dir_credits:       Total number of directed credits in the
> +				       device.
> +
> +		num_dir_ports:	       Total number of directed ports (and
> +				       queues) in the device.
> +
> +		num_hist_list_entries: Total number of history list entries in
> +				       the device.
> +
> +		num_ldb_credits:       Total number of load-balanced credits in
> +				       the device.
> +
> +		num_ldb_ports:	       Total number of load-balanced ports in
> +				       the device.
> +
> +		num_cos<M>_ldb_ports:  Total number of load-balanced ports
> +				       belonging to class-of-service M in the
> +				       device.
> +
> +		num_ldb_queues:	       Total number of load-balanced queues in
> +				       the device.
> +
> +		num_sched_domains:     Total number of scheduling domains in the
> +				       device.
> +

Sysfs is only slightly better than /proc as an API.
If it is just for testing than debugfs might be better.

Could this be done with a real netlink interface?
Maybe as part of devlink?