[lsr0]

These results aren't reproducible when both are compiled with -O3 (similar results with -O2):

  ojc_parse_str    1000000 entries in  709.300 msecs. ( 1409 iterations/msec)
  simdjson_parse   1000000 entries in  450.724 msecs. ( 2218 iterations/msec)

In those results simdjson is roughly 60% faster.

Telling simdjson we have aligned input gives us further improvement:

  simdjson_parse   1000000 entries in  369.234 msecs. ( 2708 iterations/msec)

About 90% faster. Example changes:

   simd_parse(const char *str, int64_t iter) {
       simdjson::dom::parser parser;
       int64_t   dt;
  +    auto   padded = simdjson::padded_string(std::string_view(str));
       int64_t   start = clock_micro();
   
       for (int i = iter; 0 < i; i--) {
  -        simdjson::dom::element doc = parser.parse(str, strlen(str));
  +        simdjson::dom::element doc = parser.parse(padded);
       }
       dt = clock_micro() - start;