Re: [Cake] [PATCH 1/3] pkt_sched.h: add support for sch_cake API

[Stephen Hemminger <stephen@networkplumber.org>]

On Tue, 21 Nov 2017 16:58:54 -0800
Dave Taht <dave@taht.net> wrote:

> Stephen Hemminger <stephen@networkplumber.org> writes:
> 
> > On Tue, 21 Nov 2017 16:09:40 -0800
> > Dave Taht <dave.taht@gmail.com> wrote:
> >  
> >>  
> >> +/* CAKE */
> >> +enum {
> >> +	TCA_CAKE_UNSPEC,
> >> +	TCA_CAKE_BASE_RATE,
> >> +	TCA_CAKE_DIFFSERV_MODE,
> >> +	TCA_CAKE_ATM,
> >> +	TCA_CAKE_FLOW_MODE,
> >> +	TCA_CAKE_OVERHEAD,
> >> +	TCA_CAKE_RTT,
> >> +	TCA_CAKE_TARGET,
> >> +	TCA_CAKE_AUTORATE,
> >> +	TCA_CAKE_MEMORY,
> >> +	TCA_CAKE_NAT,
> >> +	TCA_CAKE_ETHERNET,
> >> +	TCA_CAKE_WASH,
> >> +	TCA_CAKE_MPU,
> >> +	TCA_CAKE_INGRESS,
> >> +	TCA_CAKE_ACK_FILTER,
> >> +	__TCA_CAKE_MAX
> >> +};
> >> +#define TCA_CAKE_MAX	(__TCA_CAKE_MAX - 1)
> >> +
> >> +struct tc_cake_traffic_stats {
> >> +	__u32 packets;
> >> +	__u32 link_ms;
> >> +	__u64 bytes;
> >> +};
> >> +
> >> +#define TC_CAKE_MAX_TINS (8)
> >> +struct tc_cake_xstats {
> >> +	__u16 version;  /* == 5, increments when struct extended */
> >> +	__u8  max_tins; /* == TC_CAKE_MAX_TINS */
> >> +	__u8  tin_cnt;  /* <= TC_CAKE_MAX_TINS */
> >> +
> >> +	__u32 threshold_rate[TC_CAKE_MAX_TINS];
> >> +	__u32 target_us[TC_CAKE_MAX_TINS];
> >> +	struct tc_cake_traffic_stats sent[TC_CAKE_MAX_TINS];
> >> +	struct tc_cake_traffic_stats dropped[TC_CAKE_MAX_TINS];
> >> +	struct tc_cake_traffic_stats ecn_marked[TC_CAKE_MAX_TINS];
> >> +	struct tc_cake_traffic_stats backlog[TC_CAKE_MAX_TINS];
> >> +	__u32 interval_us[TC_CAKE_MAX_TINS];
> >> +	__u32 way_indirect_hits[TC_CAKE_MAX_TINS];
> >> +	__u32 way_misses[TC_CAKE_MAX_TINS];
> >> +	__u32 way_collisions[TC_CAKE_MAX_TINS];
> >> +	__u32 peak_delay_us[TC_CAKE_MAX_TINS]; /* ~= bulk flow delay */
> >> +	__u32 avge_delay_us[TC_CAKE_MAX_TINS];
> >> +	__u32 base_delay_us[TC_CAKE_MAX_TINS]; /* ~= sparse flows delay */
> >> +	__u16 sparse_flows[TC_CAKE_MAX_TINS];
> >> +	__u16 bulk_flows[TC_CAKE_MAX_TINS];
> >> +	__u16 unresponse_flows[TC_CAKE_MAX_TINS]; /* v4 - was u32 last_len */
> >> +	__u16 spare[TC_CAKE_MAX_TINS]; /* v4 - split last_len */
> >> +	__u32 max_skblen[TC_CAKE_MAX_TINS];
> >> +	__u32 capacity_estimate;  /* version 2 */
> >> +	__u32 memory_limit;       /* version 3 */
> >> +	__u32 memory_used;	  /* version 3 */
> >> +	struct tc_cake_traffic_stats ack_drops[TC_CAKE_MAX_TINS]; /* v5 */
> >> +};
> >> +  
> >
> > Rather than passing one big structure (like xstats) through netlink, it is more typical
> > to break it into separate TLV items.  
> 
> This is an API in its 5th revision over four years. If ever there were a
> time to break it and do something saner, it would be now, of course.

An example of split out stats is if IFLA_VF_STATS_xxx
Not sure if it is better, but it is expandable.