Dependency distance¶

Generated workload catalogue · Execution contract

Purpose¶

Vary how many independent accumulators are interleaved while preserving the arithmetic instruction count.

Setup¶

Property	Value
Workload ID	`dependency`
Selection	`--workload dependency`
Generator	`buildRV32IBenchmark() in RV32IBenchmarks.cpp`
End condition	EBREAK after the loop and result store

x16..x23 start at 1..8. --distance is one of 1, 2, 4, 8; default 1.

Use the shared address map and parameter bounds. N includes any training iterations; n means size.

Implementation¶

Execute 64 ADDI +1 instructions per outer iteration, rotating across the first distance accumulators. Sum all eight at completion.

for (unsigned k = 0; k < 64; ++k) ++chains[k % distance];

This is a behavioral summary of the generated assembly, not the host program being timed.

Expected result¶

Result = (36 + 64*N) modulo 2^32, independent of distance. For N=2 the result is 164. The identical checksum permits a controlled distance comparison.

The runner checks the generator's expected result in addition to retirement-by-retirement oracle validation. Output-array assertions, where described, check more than a checksum.

Measurement and running¶

Vary only distance and target. A larger distance gives the producer more cycles before its next consumer, while body work stays fixed.

build/rv32i_experiment --core advanced --workload dependency \
  --iterations 2 --size 16 --seed 1 --distance 4 \
  --fidelity behavioral --period 4000 \
  --allocation-limit-mib 512 --max-cycles 4096

The explicit period is for a bounded functional check, not a hardware-speed result. For comparisons, use the serial campaign driver, identical case inputs, and a certified per-target clock.

Source and tests¶

src/analysis/RV32IBenchmarks.cpp: emitted instructions and independent expected results.
tests/cpp/RV32IBenchmarkTest.cpp: generator results, parameter bounds, and edge cases.
tests/checks/RV32IBenchmarkCLITest.py and tests/checks/BenchmarkCampaignCLITest.py: shared execution/campaign checks.