Back to General and Gameplay Programming

my c++ d c# benchmark!

Kambiz · 2006-10-13T08:18:40

Today I saw the D's pi computing sample (\dmd\samples\d\pi.d) and thought that porting it to c++ and c# for making a little benchmark should be easy: d: import std.c.stdio; import std.c.stdlib; import std.c.time; const int LONG_TIME=4000; byte[] p; byte[] t; int q; int main(char[][] args) { int startime, endtime; int i; if (args.length == 2) { sscanf(&args[1][0],"%d",&q); } else { printf("Usage: pi [precision]\n"); exit(55); } if (q < 0) { printf("Precision was too low, running with precision of 0.\n"); q = 0; } if (q > LONG_TIME) { printf("Be prepared to wait a while...\n"); } // Compute one more digit than we display to compensate for rounding q++; p.length = q + 1; t.length = q + 1; /* compute pi */ std.c.time.time(&startime); arctan(2); arctan(3); mul4(); std.c.time.time(&endtime); // Return to the number of digits we want to display q--; /* print pi */ printf("pi = %d.",cast(int)(p[0])); for (i = 1; i <= q; i++) printf("%d",cast(int)(p)); printf("\n"); printf("%ld seconds to compute pi with a precision of %d digits.\n",endtime-startime,q); return 0; } void arctan(int s) { int n; t[0] = 1; div(s); /* t[] = 1/s */ add(); n = 1; do { mul(n); div(s * s); div(n += 2); if (((n-1) / 2) % 2 == 0) add(); else sub(); } while (!tiszero()); } void add() { int j; for (j = q; j >= 0; j--) { if (t[j] + p[j] > 9) { p[j] += t[j] - 10; p[j-1] += 1; } else p[j] += t[j]; } } void sub() { int j; for (j = q; j >= 0; j--) if (p[j] < t[j]) { p[j] -= t[j] - 10; p[j-1] -= 1; } else p[j] -= t[j]; } void mul(int multiplier) { int b; int i; int carry = 0, digit = 0; for (i = q; i >= 0; i--) { b = (t * multiplier + carry); digit = b % 10; carry = b / 10; t = digit; } } /* t[] /= l */ void div(int divisor) { int i, b; int quotient, remainder = 0; for (i = 0; i <= q; i++) { b = (10 * remainder + t); quotient = b / divisor; remainder = b % divisor; t = quotient; } } void div4() { int i, c, d = 0; for (i = 0; i <= q; i++) { c = (10 * d + p) / 4; d = (10 * d + p) % 4; p = c; } } void mul4() { int i, c, d; d = c = 0; for (i = q; i >= 0; i--) { d = (p * 4 + c) % 10; c = (p * 4 + c) / 10; p = d; } } int tiszero() { int k; for (k = 0; k <= q; k++) if (t[k] != 0) return false; return true; } (I compiled pi.d with dmd -O -release pi.d) c++: #include <stdio.h> #include <stdlib.h> #include <time.h> #define LONG_TIME 4000 __int8* p; __int8* t; int q; void arctan(int s); void add(); void sub(); void mul(int); void div(int); void mul4(); void div4(); int tiszero(); int main(int argv,char** args) { time_t startime, endtime; int i; if (argv == 2) { sscanf(&args[1][0],"%d",&q); } else { printf("Usage: pi [precision]\n"); exit(55); } if (q < 0) { printf("Precision was too low, running with precision of 0.\n"); q = 0; } if (q > LONG_TIME) { printf("Be prepared to wait a while...\n"); } // Compute one more digit than we display to compensate for rounding q++; p = new __int8[ q + 1 ]; t = new __int8[ q + 1 ]; for(int tt=0;tt<=q;tt++) { p=0; t=0; } /* compute pi */ time(&startime); arctan(2); arctan(3); mul4(); time(&endtime); // Return to the number of digits we want to display q--; /* print pi */ printf("pi = %d.",(int)(p[0])); for (i = 1; i <= q; i++) printf("%d",(int)(p)); printf("\n"); printf("%ld seconds to compute pi with a precision of %d digits.\n",(long)endtime-(long)startime,q); delete [] p; delete [] t; return 0; } void arctan(int s) { int n; t[0] = 1; div(s); /* t[] = 1/s */ add(); n = 1; do { mul(n); div(s * s); div(n += 2); if (((n-1) / 2) % 2 == 0) add(); else sub(); } while (!tiszero()); } void add() { int j; for (j = q; j >= 0; j--) { if (t[j] + p[j] > 9) { p[j] += t[j] - 10; p[j-1] += 1; } else p[j] += t[j]; } } void sub() { int j; for (j = q; j >= 0; j--) if (p[j] < t[j]) { p[j] -= t[j] - 10; p[j-1] -= 1; } else p[j] -= t[j]; } void mul(int multiplier) { int b; int i; int carry = 0, digit = 0; for (i = q; i >= 0; i--) { b = (t * multiplier + carry); digit = b % 10; carry = b / 10; t = digit; } } /* t[] /= l */ void div(int divisor) { int i, b; int quotient, remainder = 0; for (i = 0; i <= q; i++) { b = (10 * remainder + t); quotient = b / divisor; remainder = b % divisor; t = quotient; } } void div4() { int i, c, d = 0; for (i = 0; i <= q; i++) { c = (10 * d + p) / 4; d = (10 * d + p) % 4; p = c; } } void mul4() { int i, c, d; d = c = 0; for (i = q; i >= 0; i--) { d = (p * 4 + c) % 10; c = (p * 4 + c) / 10; p = d; } } int tiszero() { int k; for (k = 0; k <= q; k++) if (t[k] != 0) return false; return true; } c#: using System; using System.Diagnostics; class Pi { static void Main(string[] args) { Pi pi = new Pi(); pi.run(args); } private const int LONG_TIME = 4000; sbyte[] p; sbyte[] t; int q; void run(string[] args) { Stopwatch timer = new Stopwatch(); int i; if (args.Length == 1) { q = int.Parse(args[0]); } else { Console.WriteLine("Usage: pi [precision]"); return; } if (q < 0) { Console.WriteLine("Precision was too low, running with precision of 0."); q = 0; } if (q > LONG_TIME) { Console.WriteLine("Be prepared to wait a while..."); } // Compute one more digit than we display to compensate for rounding q++; p = new sbyte[q + 1]; t = new sbyte[q + 1]; /* compute pi */ timer.Start(); arctan(2); arctan(3); mul4(); timer.Stop(); // Return to the number of digits we want to display q--; /* print pi */ Console.Write("pi = {0}.", p[0]); for (i = 1; i <= q; i++) Console.Write(p); Console.WriteLine(); Console.WriteLine("{0} seconds to compute pi with a precision of {1} digits.", timer.ElapsedMilliseconds / 1000.0, q); return; } void arctan(int s) { int n; t[0] = 1; div(s); /* t[] = 1/s */ add(); n = 1; do { mul(n); div(s * s); div(n += 2); if (((n - 1) / 2) % 2 == 0) add(); else sub(); } while (!tiszero()); } void add() { int j; for (j = q; j >= 0; j--) { if (t[j] + p[j] > 9) { p[j] += (sbyte)(t[j] - 10); p[j - 1] += 1; } else p[j] += t[j]; } } void sub() { int j; for (j = q; j >= 0; j--) if (p[j] < t[j]) { p[j] -= (sbyte)(t[j] - 10); p[j - 1] -= 1; } else p[j] -= t[j]; } void mul(int multiplier) { int b; int i; int carry = 0, digit = 0; for (i = q; i >= 0; i--) { b = (t * multiplier + carry); digit = b % 10; carry = b / 10; t = (sbyte)digit; } } /* t[] /= l */ void div(int divisor) { int i, b; int quotient, remainder = 0; for (i = 0; i <= q; i++) { b = (10 * remainder + t); quotient = b / divisor; remainder = b % divisor; t = (sbyte)quotient; } } void div4() { int i, c, d = 0; for (i = 0; i <= q; i++) { c = (10 * d + p) / 4; d = (10 * d + p) % 4; p = (sbyte)c; } } void mul4() { int i, c, d; d = c = 0; for (i = q; i >= 0; i--) { d = (p * 4 + c) % 10; c = (p * 4 + c) / 10; p = (sbyte)d; } } bool tiszero() { int k; for (k = 0; k <= q; k++) if (t[k] != 0) return false; return true; } } I used the release builds for the benchmark, here are the results: d : 26 seconds to compute pi with a precision of 10000 digits. c# : 34,745(34.745) seconds to compute pi with a precision of 10000 digits. c++ : 15 seconds to compute pi with a precision of 10000 digits. I do not want to start a language war... we had enough such wars in the past days and I have just made this benchmark because I saw the “What do you think of the D language?“ thread and was testing d. I'm just surprised a little: I thought that D shouldn't be much slower than c++ and I thought that c# would be much faster. Maybe there is some optimization option I have not used(?) What do you think about the results? (maybe some one can test java) (I really like the invariant and unittest features of D, are there equivalents for c#?) -I can't reply until tomorrow- [Edited by - Kambiz on October 7, 2006 2:02:45 AM]

General and Gameplay Programming Programming Unity

Started by Kambiz October 06, 2006 06:40 PM

70 comments, last by Raghar 17 years, 6 months ago

Kambiz

759

Author

October 08, 2006 05:06 AM

Anonymous

October 08, 2006 05:49 AM

Quote:Original post by Kambiz
I thought that JIT compilation can produce more efficient code because it can optimize for the target machine.

But it has less time to compile. Obviously it can't spend a minute optimizing some small program that would run in 20 seconds without full optimizations. But C compilation can take as long as necessary to make the best output code.

h3r3tic

228

October 08, 2006 05:55 AM

Kambiz, I encourage you to add the GDC D compiler to the charts :)
http://gdcwin.sourceforge.net/

PlayerX

279

October 08, 2006 07:02 AM

Out of curiosity I implemented it in i386 machine code - it ended up 2 seconds slower than the C++ compiled version. At a guess (apart from shoddy code of course) I'd say it's because the compiler was more willing to unroll loops than I was. :)

cody

199

October 08, 2006 07:49 AM

nice benchmark. but of course it doesnt cover all performance relevant aspects.

i would like to see a memory allocation benchmark. with lots of news and deletes. i guess the managed version will be better there.

Kambiz

759

Author

October 08, 2006 09:40 AM

Quote:Original post by h3r3tic
Kambiz, I encourage you to add the GDC D compiler to the charts :)
http://gdcwin.sourceforge.net/

I can not compile using gdmd I get this error message:
object.d: module object cannot read file 'object.d'
I have never used those GNU compilers, can you tell me the correct command line arguments?
I have tried “gdmd pi.d -O -release” with “C:\MinGW\include\d\3.4.5” added to the PATH variable.
-I have to work now later I will try this again.-

Quote:Original post by cody
nice benchmark. but of course it doesnt cover all performance relevant aspects.

i would like to see a memory allocation benchmark. with lots of news and deletes. i guess the managed version will be better there.

I agree.

h3r3tic

228

October 08, 2006 11:28 AM

Quote:Original post by Kambiz
I can not compile using gdmd I get this error message:
object.d: module object cannot read file 'object.d'
I have never used those GNU compilers, can you tell me the correct command line arguments?
I have tried “gdmd pi.d -O -release” with “C:\MinGW\include\d\3.4.5” added to the PATH variable.
-I have to work now later I will try this again.-

The error message means that it cannot find gphobos, the GDC standard library. It could mean a MinGW or GDC installation problem, but I'm not sure what exactly in this case. You could try adding 'C:\MinGW\include\d\3.4.5' to your path. I have mostly used DMD so I can't really help much in this case. On a last note, maybe it's a problem with GDC based on GCC 3.4.5 ? I've got the one based on 3.4.2 and it seems to work fine
As for the command line arguments, both:
> gdmd -inline -release -O pi.d
and
> gdc -frelease -finline -O3 pi.d
worked for me

Stachel

100

October 08, 2006 11:56 AM

Quote:Original post by cody
nice benchmark. but of course it doesnt cover all performance relevant aspects.

Here's a benchmark showing that low level code generation doesn't always matter, sometimes higher level features matter much more:

http://www.digitalmars.com/d/cppstrings.d

Scroll down to see the benchmark.

clayasaurus

139

October 08, 2006 12:46 PM

I believe you mean http://digitalmars.com/d/cppstrings.html

DaveJF

118

October 08, 2006 01:29 PM

Quote:Original post by Kambiz
I'm just surprised a little: I thought that D shouldn't be much slower than c++ and I thought that c# would be much faster. Maybe there is some optimization option I have not used(?)

What do you think about the results?

Which version of DMD? With v0.169 of DMD (the latest just posted) and the .NET 2.0 runtime I got:

Intel 2.2 Ghz:
CPP 2.28 (cl /Ox /TP)
D 2.26 (dmd -O -inline -release)
C# 4.52 (csc /optimize+ /checked- /unsafe+)

AMD 3200+
CPP 1.43
D 1.46
C# 3.25

Check this for some other comparisons:

Computer Language Shootout

my c++ d c# benchmark!

This topic is closed to new replies.

Popular Topics

Recommended Tutorials

my c++ d c# benchmark!

This topic is closed to new replies.

Popular Topics

Recommended Tutorials

Reticulating splines