Re: [PATCH net-next 12/20] net: hns3: Add packet statistics of netdev

Jakub Kicinski
2018-01-09T01:46:14Z

On Mon, 08 Jan 2018 20:39:13 -0500 (EST), David Miller wrote:
> From: Jakub Kicinski <kubakici@wp.pl>
> Date: Mon, 8 Jan 2018 12:04:31 -0800
>
> > Ugh, I so didn't review this in time :( I think there is a consensus
> > that we should avoid duplicating standard stats in ethtool. Especially
> > those old ones. Like "collisions", I assume this is a modern NIC, are
> > collisions still a thing?
>
> There is no standard way to get per-queue values, and ethtool stats are
> how pretty much every driver provides it.

Right, agreed. I'm only objecting to this patch (12/20), where we can
see the telltale code like this:

+ const struct rtnl_link_stats64 *net_stats;
+ struct rtnl_link_stats64 temp;
+
+ net_stats = dev_get_stats(netdev, &temp);
+ for (i = 0; i < HNS3_NETDEV_STATS_COUNT; i++) {
+ stat = (u8 *)net_stats + hns3_netdev_stats[i].stats_offset;
+ *data++ = *(u64 *)stat;
+ }

Where:

+#define HNS3_NETDEV_STAT(_string, _member) { \
+ .stats_string = _string, \
+ .stats_offset = offsetof(struct rtnl_link_stats64, _member) \
+}
+
+static const struct hns3_stats hns3_netdev_stats[] = {
+ /* Rx per-queue statistics */
+ HNS3_NETDEV_STAT("rx_packets", rx_packets),
+ HNS3_NETDEV_STAT("tx_packets", tx_packets),

etc. IOW dumping struct rtnl_link_stats64 to ethtool -S member by
member.

Let me put the netlink per-queue stats on my soft TODO list :)