Specific to your 2nd question
No, 1 line does not equal 1 operation
Different instructions can take multiple operations to complete
Also different instructions work on different sized registers
A single instruction may require 3 processor cycles to complete, but process only 32 bits of data. A single instruction may require a single processor cycle to complete, but process 128 bits of data.
A complete algorithm is generally benchmarked as cycles per input byte or as cycles per invocation, depending on the type of algorithm. The result is dependent on processor architecture and implementation but independent of clock speed. Algorithms that accept variable input lengths such as hash functions are benchmarked with a variety of input lengths, as their performance will vary with input length.