On Thu, 3 Sep 2020 16:40:54 -0600 David Ahern wrote:
> On 9/2/20 8:03 PM, Jakub Kicinski wrote:
> > +sysfs
> > +-----
> > +
> > +Each device directory in sysfs contains a `statistics` directory (e.g.
> > +`/sys/class/net/lo/statistics/`) with files corresponding to
> > +members of :c:type:`struct rtnl_link_stats64 <rtnl_link_stats64>`.
> > +
> > +This simple interface is convenient especially in constrained/embedded
> > +environments without access to tools. However, it's sightly inefficient
>
> sightly seems like the wrong word. Did you mean 'highly inefficient'?
Indeed, I'll drop the "slightly". Hopefully the info below is clear
enough for users to understand what's happening.
> > +when reading multiple stats as it internally performs a full dump of
> > +:c:type:`struct rtnl_link_stats64 <rtnl_link_stats64>`
> > +and reports only the stat corresponding to the accessed file.
> > +
> > +Sysfs files are documented in
> > +`Documentation/ABI/testing/sysfs-class-net-statistics`.
> > +
> > +
> > +netlink
> > +-------
> > +
> > +`rtnetlink` (`NETLINK_ROUTE`) is the preferred method of accessing
> > +:c:type:`struct rtnl_link_stats64 <rtnl_link_stats64>` stats.
> > +
> > +Statistics are reported both in the responses to link information
> > +requests (`RTM_GETLINK`) and statistic requests (`RTM_GETSTATS`,
> > +when `IFLA_STATS_LINK_64` bit is set in the `.filter_mask` of the request).
> > +
> > +ethtool
> > +-------
> > +
> > +Ethtool IOCTL interface allows drivers to report implementation
> > +specific statistics.
>
> an example here would be helpful. e.g., I use `ethool -S` primarily for
> per queue stats which show more details than the other APIs which show
> aggregated stats.
I'll mention the queue stats here.
> > diff --git a/include/uapi/linux/if_link.h b/include/uapi/linux/if_link.h
> > index 7fba4de511de..6ea0fb48739e 100644
> > --- a/include/uapi/linux/if_link.h
> > +++ b/include/uapi/linux/if_link.h
> > @@ -40,26 +40,191 @@ struct rtnl_link_stats {
> > __u32 rx_nohandler; /* dropped, no handler found */
> > };
> >
> > -/* The main device statistics structure */
> > +/**
> > + * struct rtnl_link_stats64 - The main device statistics structure.
> > + *
> > + * @rx_packets: Number of good packets received by the interface.
> > + * For hardware interfaces counts all good packets seen by the host,
> > + * including packets which host had to drop at various stages of
> > processing
> > + * (even in the driver).
> > + *
> > + * @tx_packets: Number of packets successfully transmitted.
> > + * For hardware interfaces counts packets which host was able to
> > successfully
> > + * hand over to the device, which does not necessarily mean that packets
> > + * had been successfully transmitted out of the device, only that device
> > + * acknowledged it copied them out of host memory.
> > + *
> > + * @rx_bytes: Number of good incoming bytes, corresponding to @rx_packets.
> >
>
> s/incoming/received/?
>
> > + *
> > + * @tx_bytes: Number of good incoming bytes, corresponding to @tx_packets.
> >
>
> s/incoming/transmitted/
:o I wonder where I got those from.
> Thanks for taking the time to work on this; I'm sure you spent a LOT of
> hours going through all of the drivers and APIs.
And "dusty datasheets" :)
