> From: Vincent Jardin [mailto:vincent.jardin at 6wind.com] > Sent: Wednesday, October 26, 2016 7:37 PM > Le 26 octobre 2016 2:11:26 PM "Van Haaren, Harry" > <harry.van.haaren at intel.com> a ?crit : > > >> -----Original Message----- > >> From: dev [mailto:dev-bounces at dpdk.org] On Behalf Of Jerin Jacob > >> > >> So far, I have received constructive feedback from Intel, NXP and Linaro > >> folks. > >> Let me know, if anyone else interested in contributing to the definition of > >> eventdev? > >> > >> If there are no major issues in proposed spec, then Cavium would like work > >> on > >> implementing and up-streaming the common code(lib/librte_eventdev/) and > >> an associated HW driver.(Requested minor changes of v2 will be addressed > >> in next version). > > > > Hi All, > > > > I will propose a minor change to the rte_event struct, allowing some bits > > to be implementation specific. Currently the rte_event struct has no space > > to allow an implementation store any metadata about the event. For software > > performance it would be really helpful if there are some bits available for > > the implementation to keep some flags about each event. > > > > I suggest to rework the struct as below which opens 6 bits that were > > otherwise wasted, and define them as implementation specific. By > > implementation specific it is understood that the implementation can > > overwrite any information stored in those bits, and the application must > > not expect the data to remain after the event is scheduled. > > > > OLD: > > struct rte_event { > > uint32_t flow_id:24; > > uint32_t queue_id:8; > > uint8_t sched_type; /* Note only 2 bits of 8 are required */ > > > > NEW: > > struct rte_event { > > uint32_t flow_id:24; > > uint32_t sched_type:2; /* reduced size : but 2 bits is enough for the > > enqueue types Ordered,Atomic,Parallel.*/ > > uint32_t implementation:6; /* available for implementation specific > > metadata */ > > uint8_t queue_id; /* still 8 bits as before */ > > Bitfileds are efficients on Octeon. What's about other CPUs you have in > mind? x86 is not as efficient.
Given the rte_event struct is 16 bytes and there's no free space to use, I see no alternative than using bitfields in this case. Wecloming suggestions of a better way to layout the structure to avoid the bitfield. Regards, -Harry
