FD.io VPP
v18.01.2-1-g9b554f3
Vector Packet Processing
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The object that is in the data-path to perform the check. More...
Data Fields | |
u16 | n_used_blocks |
The number of blocks from the 'block' array below that have rnages configured. More... | |
u16 | n_free_ranges |
The total number of free ranges from all blocks. More... | |
protocol_port_range_t | blocks [N_BLOCKS_PER_DPO] |
the fixed size array of ranges More... | |
The object that is in the data-path to perform the check.
Some trade-offs here; memory vs performance.
performance: the principle factor is d-cache line misses/hits. so we want the data layout to minimise the d-cache misses. This means not following dependent reads. i.e. not doing
struct B { u16 n_ranges; range_t *ragnes; // vector of ranges. }
so to read ranges[0] we would first d-cache miss on the address of the object of type B, for which we would need to wait before we can get the address of B->ranges. So this layout is better:
struct B { u16 n_ranges; range_t ragnes[N]; }
memory: the latter layout above is more memory hungry. And N needs to be: 1 - sized for the maximum required 2 - fixed, so that objects of type B can be pool allocated and so 'get'-able using an index. An option over fixed might be to allocate contiguous chunk from the pool (like we used to do for multi-path adjs).
Definition at line 102 of file ip_source_and_port_range_check.h.
protocol_port_range_t protocol_port_range_dpo_t_::blocks[N_BLOCKS_PER_DPO] |
the fixed size array of ranges
Definition at line 120 of file ip_source_and_port_range_check.h.
u16 protocol_port_range_dpo_t_::n_free_ranges |
The total number of free ranges from all blocks.
Used to prevent overrun of the ranges available.
Definition at line 115 of file ip_source_and_port_range_check.h.
u16 protocol_port_range_dpo_t_::n_used_blocks |
The number of blocks from the 'block' array below that have rnages configured.
We keep this count so that in the data-path we can limit the loop to be only over the blocks we need
Definition at line 109 of file ip_source_and_port_range_check.h.