C++Talk.NET C++ language newsgroups   Archives   FAQ   Search   Memberlist   Usergroups   Register   Profile   Log in to check your private messages   Log in  Performance Question          C++Talk.NET Forum Index -> C++ language (comp.lang.c++) View previous topic :: View next topic   Author Message BCC Guest Posted: Thu Feb 26, 2004 11:11 pm    Post subject: Performance Question Why the huge drop in performance in STL from VC6.0 to VC7.1? Particularly with vector? The following code shows what I mean... Any thoughts? Thanks, B //Test the speed of operations on primitive arrays and vectors #pragma warning(disable: 4786) #include <vector> #include <time.h> #include <iostream> using namespace std; typedef vector<int> IntVec; int main(int argc, char* argv[]) { clock_t start, finish; start = clock(); const int dim1 = 1000; const int dim2 = 10000; int* matrix[dim1]; for(int i = 0; i < dim1; i++) { matrix[i] = new int[dim2]; for(int j = 0; j < dim2; j++) matrix[i][j] = j; } finish = clock(); cout << "Total time taken for " << dim1 << "x" << dim2; cout << " int array operations: "; cout << double(finish-start) / CLOCKS_PER_SEC << " seconds" << endl; for( i = 0; i < dim1; i++) { delete[] matrix[i]; } start = clock(); vector for( i = 0; i < dim1; i++) { intvecs[i].resize(dim2); for(int j = 0; j < dim2; j++) intvecs[i][j] = j; } finish = clock(); cout << "Total time taken for " << dim1 << "x" << dim2; cout << " int vector operations: "; cout << double(finish-start) / CLOCKS_PER_SEC << " seconds" << endl; return 0; } /** * ========================== output from VC6.0: Total time taken for 1000x10000 int array operations: 0.12 seconds Total time taken for 1000x10000 int vector operations: 0.14 seconds ========================== output from VC7.1: Total time taken for 1000x10000 int array operations: 0.12 seconds Total time taken for 1000x10000 int vector operations: 1.231 seconds ========================== */ Back to top Jonathan Turkanis Guest Posted: Thu Feb 26, 2004 11:23 pm    Post subject: Re: Performance Question "BCC" <bryan (AT) akanta (DOT) com> wrote Quote: Why the huge drop in performance in STL from VC6.0 to VC7.1? Particularly with vector? The following code shows what I mean... Here are my results: VC7.1: Total time taken for 1000x10000 int array operations: 0.062 seconds Total time taken for 1000x10000 int vector operations: 0.094 seconds VC6.5: Total time taken for 1000x10000 int array operations: 0.062 seconds Total time taken for 1000x10000 int vector operations: 0.235 seconds Are you sure you have optimizations turned on? Jonathan Back to top Andre Kostur Guest Posted: Thu Feb 26, 2004 11:24 pm    Post subject: Re: Performance Question "BCC" <bryan (AT) akanta (DOT) com> wrote in news:m2v%b.30906$Ql.1344 (AT) newssvr25 (DOT) news.prodigy.com: Quote: Why the huge drop in performance in STL from VC6.0 to VC7.1? Particularly with vector? The following code shows what I mean... Any thoughts? Thanks, B //Test the speed of operations on primitive arrays and vectors #pragma warning(disable: 4786) #include <vector #include #include using namespace std; typedef vector int main(int argc, char* argv[]) { clock_t start, finish; start = clock(); const int dim1 = 1000; const int dim2 = 10000; int* matrix[dim1]; for(int i = 0; i < dim1; i++) { matrix[i] = new int[dim2]; for(int j = 0; j < dim2; j++) matrix[i][j] = j; } finish = clock(); cout << "Total time taken for " << dim1 << "x" << dim2; cout << " int array operations: "; cout << double(finish-start) / CLOCKS_PER_SEC << " seconds" << endl; for( i = 0; i < dim1; i++) { delete[] matrix[i]; } start = clock(); vector for( i = 0; i < dim1; i++) { intvecs[i].resize(dim2); for(int j = 0; j < dim2; j++) intvecs[i][j] = j; } finish = clock(); cout << "Total time taken for " << dim1 << "x" << dim2; cout << " int vector operations: "; cout << double(finish-start) / CLOCKS_PER_SEC << " seconds" << endl; return 0; } /** * ========================== output from VC6.0: Total time taken for 1000x10000 int array operations: 0.12 seconds Total time taken for 1000x10000 int vector operations: 0.14 seconds ========================== output from VC7.1: Total time taken for 1000x10000 int array operations: 0.12 seconds Total time taken for 1000x10000 int vector operations: 1.231 seconds ========================== */ Well... 2 things 1) This is compiler-specific, thus offtopic for comp.lang.c++ 2) Were these compiled in "release" mode and not "debug" mode? Back to top BCC Guest Posted: Fri Feb 27, 2004 12:00 am    Post subject: Re: Performance Question "Jonathan Turkanis" <technews (AT) kangaroologic (DOT) com> wrote Quote: "BCC" <bryan (AT) akanta (DOT) com> wrote in message news:m2v%b.30906$Ql.1344 (AT) newssvr25 (DOT) news.prodigy.com... Why the huge drop in performance in STL from VC6.0 to VC7.1? Particularly with vector? The following code shows what I mean... Here are my results: VC7.1: Total time taken for 1000x10000 int array operations: 0.062 seconds Total time taken for 1000x10000 int vector operations: 0.094 seconds VC6.5: Total time taken for 1000x10000 int array operations: 0.062 seconds Total time taken for 1000x10000 int vector operations: 0.235 seconds Are you sure you have optimizations turned on? Jonathan I think so... are you sure you are using it's 7.1 and not 7.0? I fiddled with the optimizations and nothing improved... for whatever reason, 7.0 is faster than 7.1 when I tested it. B Back to top Jonathan Turkanis Guest Posted: Fri Feb 27, 2004 12:07 am    Post subject: Re: Performance Question "BCC" <bryan (AT) akanta (DOT) com> wrote Quote: I think so... are you sure you are using it's 7.1 and not 7.0? I fiddled with the optimizations and nothing improved... for whatever reason, 7.0 is faster than 7.1 when I tested it. Yes. I have all three, but VC7.0 is not working and needs to be reinstalled. As Andre pointed out, this thread is off topic. You can probably get a good response at microsoft.public.dotnet.languages.vc People from Microsoft and Dinkumware read this group and often answer questions like this. Jonathan Back to top BCC Guest Posted: Fri Feb 27, 2004 12:17 am    Post subject: Re: Performance Question Quote: As Andre pointed out, this thread is off topic. You can probably get a good response at microsoft.public.dotnet.languages.vc People from Microsoft and Dinkumware read this group and often answer questions like this. Right on. I actually posted a question earlier about where to ask this question, but my post never showed up... go figure. Ill take it over there, thanks. B Back to top Display posts from previous: All Posts1 Day7 Days2 Weeks1 Month3 Months6 Months1 Year Oldest FirstNewest First         C++Talk.NET Forum Index -> C++ language (comp.lang.c++) All times are GMT Page 1 of 1   Jump to: Select a forum C/C++----------------C LanguageC Language (Moderated)C++ Language (Moderated)C++ language (comp.lang.c++)C++ language, library and standards Non-English C/C++ Newsgroups----------------C++ (German)C++ (French)  You cannot post new topics in this forum You cannot reply to topics in this forum You cannot edit your posts in this forum You cannot delete your posts in this forum You cannot vote in polls in this forum Powered by phpBB © 2001, 2006 phpBB Group SEO toolkit © 2004-2006 webmedic.