NXP Semiconductors QorIQ LS1012A Reference Manual

If you enable regulation, the following programmable values set the permitted number ofoutstanding transactions:• OT integer.• OT fraction.NOTE• Outstanding transaction regulation only counts transactionswith a zero QoS value.• Outstanding transaction regulation does not count oroverride transactions that have no data associated withthem. These transactions are:• CleanUnique .• MakeUnique .• CleanShared .• CleanInvalid .• MakeInvalid .• Evict .• Barriers.• DVM transactions.Read Queue Slot ReservationEach master interface of the CCI-400 has a queue that stores read requests. If thisbecomes full with low priority requests, higher priority requests are blocked. To avoidthis, the CCI-400 reserves a number of slots for high priority requests and a number ofslots for high or medium priority requests. Table Regulation based on outstandingtransactions shows a summary of the possible configurations.Table 9-4. Slots reserved for high and medium priority traffic in each master interfaceRead tracker size, as determined bythe Mlx_R_MAX parameterNumber of reserved slots for mediumor high priority requestsNumber of reserved slots for onlyhigh priority requests2-4 0 05-7 0 18-15 1 116-128 3 1For example, assume the read tracker size is 32, implying that three slots are reserved formedium to high priority requests and one slot is reserved for high priority requests. In thiscase:• The maximum number of slots available for high priority requests is 32.• The maximum number of slots available for medium priority requests is 32 - 1 = 31.• The maximum number of slots available for low priority requests is 32 - 3 - 1 = 28.Chapter 9 Cache Coherent Interconnect (CCI-400)QorIQ LS1012A Reference Manual, Rev. 1, 01/2018NXP Semiconductors 345