Just a thought: It would be an interesting experiment to count the memory usage in the C++ version of the benchmark to match Java's memory consumption (1.5-2.5 GB) and to deallocate only those C++ objects which increase memory consumption beyond this limit. At the end of the benchmark, C++ could just leave the 1.5-2.5 GB of object-bytes on the heap, without ever deallocating them in C++, and return from the main() function to take advantage of the fact that the memory will be deallocated by the operating system when the benchmark process terminates.
In a radical version of this idea, all calls to free() and delete that do not have side-effects and do not cause data cache trashing could in any C++ application be no-ops (empty operations) until memory consumption reaches 1 GB. Memory allocation until 1 GB is reached is of course just an ADD instruction, because that memory will never be reused for other objects. Maybe this strategy is a part of how Java is able to outperform C++. On Thursday, February 13, 2020 at 6:33:55 PM UTC+1, Robert Engels wrote: > > I won't dispute that, but at least this particular case, it requires > on-going maintenance by the developer (company). In this case of Java very > few performance improvements have required code changes. > > Using a different structure entirely (hash map vs. tree map) is a > different issue - it touches on the robustness of the stdlib, dynamic > runtime class replacement, etc. I can only assume that std::map was used > because it made the code easier/portable to write in C++ rather than adding > an outside dependency or custom hash map. implementation (In the Java code, > they use a custom IntegerSet, IntegerList to avoid boxing...) > > -----Original Message----- > From: ⚛ <0xe2.0...@gmail.com <javascript:>> > Sent: Feb 13, 2020 9:57 AM > To: golang-nuts > Subject: Re: [go-nuts] Go without garbage collector > > On Thursday, February 13, 2020 at 3:05:45 PM UTC+1, Robert Engels wrote: >> >> The code hasn’t been changed. The performance numbers have changed >> dramatically with no developer intervention. No “hand optimizing” required. >> > > C++ evolves over time also. Hashmaps have been added to C++ in C++11, > which from today's viewpoint invalidates most benchmarks published before > year 2011 that translated Java's HashMap to C++'s std::map. > > -- > You received this message because you are subscribed to the Google Groups > "golang-nuts" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to golan...@googlegroups.com <javascript:>. > To view this discussion on the web visit > https://groups.google.com/d/msgid/golang-nuts/f5a4a3cf-e4ce-4fb4-af03-fa5f32a5ce62%40googlegroups.com > > <https://groups.google.com/d/msgid/golang-nuts/f5a4a3cf-e4ce-4fb4-af03-fa5f32a5ce62%40googlegroups.com?utm_medium=email&utm_source=footer> > . > > > > > -- You received this message because you are subscribed to the Google Groups "golang-nuts" group. To unsubscribe from this group and stop receiving emails from it, send an email to golang-nuts+unsubscr...@googlegroups.com. To view this discussion on the web visit https://groups.google.com/d/msgid/golang-nuts/33723531-2ad2-4161-ae3e-14ec375cbb90%40googlegroups.com.
