processor-to-logic latency, AXI link: one board, the engine at its measured clock
  timer: CNTVCT_EL0 at 99.999 MHz, one tick 10.0 ns
  the timer alone (two reads, an ISB each)                   median      10 ns  p10      10  p90      20  p99      20  max    18810  mean      12  (n 20000)
  EMIO signature read (a processor GPIO register)            median     230 ns  p10     230  p90     240  p99     240  max    28140  mean     236  (n 100000)
  AXI-Lite read, a link register                             median     230 ns  p10     230  p90     230  p99     230  max    22360  mean     233  (n 100000)
  AXI-Lite read, an engine register                          median     240 ns  p10     240  p90     240  p99     240  max    21600  mean     242  (n 100000)
  AXI-Lite write, a link register                            median      10 ns  p10      10  p90      20  p99      20  max    10370  mean      14  (n 100000)
  AXI-Lite write, an engine register                         median      10 ns  p10      10  p90      20  p99      20  max    38470  mean      14  (n 100000)
  AXI-Lite write then read (select a cell, read its field)   median     460 ns  p10     460  p90     580  p99     600  max    47820  mean     481  (n 100000)
  guarded read, as every job access goes (signature, then read) median     470 ns  p10     460  p90     470  p99     470  max    19920  mean     469  (n 100000)
  a 1-entry write list by DMA, kick to done (4 writes, polls) median    7460 ns  p10    7340  p90    7790  p99    9400  max    28330  mean    7645  (n 5000)
  a 512-entry write list by DMA (one page), kick to done     median   20020 ns  p10   19740  p90   20260  p99   29510  max    53911  mean   20197  (n 2000)
    = 39.1 ns an entry, 25.6 M register writes/s
  AXI, DMA and sequencer: a full table (64 levels x 128 fields, 32835 register writes): median 3.82 ms of 6, 116 ns a write
  AXI, DMA and sequencer: 65536 chains of 8 cells x 4 sweeps: 0.436 s, 6.65 us a chain, 150472 chains/s
  AXI, plain register accesses: a full table (64 levels x 128 fields, 32835 register writes): median 17.48 ms of 6, 532 ns a write
  AXI, plain register accesses: 16384 chains of 8 cells x 4 sweeps: 0.154 s, 9.43 us a chain, 106053 chains/s
  AXI accesses 1387388, DMA lists 8862, sequencer batches 257