Very poor boost::lexical_cast performance

Question

Windows XP SP3. Core 2 Duo 2.0 GHz. I\'m finding the boost::lexical_cast performance to be extremely slow. Wanted to find out ways to speed up the code. Using /O2 optimizati

Answer 1

lexical_cast may or may not be as slow in relation to Java and Python as your bencharks indicate because your benchmark measurements may have a subtle problem. Any workspace allocations/deallocations done by lexical cast or the iostream methods it uses are measured by your benchmarks because C++ doesn't defer these operations. However, in the case of Java and Python, the associated deallocations may in fact have simply been deferred to a future garbage collection cycle and missed by the benchmark measurements. (Unless a GC cycle by chance occurs while the benchmark is in progress and in that case you'd be measuring too much). So it's hard to know for sure without examining specifics of the Java and Python implementations how much "cost" should be attributed to the deferred GC burden that may (or may not) be eventually imposed.

This kind of issue obviously may apply to many other C++ vs garbage collected language benchmarks.