net-timestamp: SCHED timestamp on entering packet scheduler

Kernel transmit latency is often incurred in the packet scheduler. Introduce a new timestamp on transmission just before entering the scheduler. When data travels through multiple devices (bonding, tunneling, ...) each device will export an individual timestamp.

Willem de Bruijn committed 12 years ago

Commit e7fd2881 parent 09c2d256 files · +31 −7Browse files

Showing the changes to include/uapi/linux (2 of 6 files). Show all

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2 files

include/uapi/linux/errqueue.h +1 −0
include/uapi/linux/net_tstamp.h +2 −1

include/uapi/linux/errqueue.h+1−0

@@ -39,6 +39,7 @@ struct scm_timestamping { · 38 unmodified lines
39	39	*/
40	40	enum {
41	41	SCM_TSTAMP_SND, /* driver passed skb to NIC, or HW */
	42	+ SCM_TSTAMP_SCHED, /* data entered the packet scheduler */
42	43	};
43	44
44	45	#endif /* _UAPI_LINUX_ERRQUEUE_H */

include/uapi/linux/net_tstamp.h+2−1

@@ -21,8 +21,9 @@ enum { · 20 unmodified lines
21	21	SOF_TIMESTAMPING_SYS_HARDWARE = (1<<5),
22	22	SOF_TIMESTAMPING_RAW_HARDWARE = (1<<6),
23	23	SOF_TIMESTAMPING_OPT_ID = (1<<7),
	24	+ SOF_TIMESTAMPING_TX_SCHED = (1<<8),
24	25
25		− SOF_TIMESTAMPING_LAST = SOF_TIMESTAMPING_OPT_ID,
	26	+ SOF_TIMESTAMPING_LAST = SOF_TIMESTAMPING_TX_SCHED,
26	27	SOF_TIMESTAMPING_MASK = (SOF_TIMESTAMPING_LAST - 1) \|
27	28	SOF_TIMESTAMPING_LAST
28	29	};