performance puzzle
-
C++ ======================================
int _tmain(int argc, _TCHAR* argv[])
{
if (argc != 2)
{
std::cerr << "Usage:\tsieve [iterations]\n";
return 1;
};size\_t NUM = \_wtoi(argv\[1\]); DWORD dw = ::GetTickCount();#if ! CS-Speed
char primes[8192+1];
int pbegin = 0;
int begin = 2;
int end = 8193;while (NUM -- != 0) { for (int i = 0; i < end; i++) { primes\[i\] = 1; } for (int i = begin; i < end; ++i) { if (primes\[i\] != 0) { int p = i; // using this extra variable speeds up C++!!! (and slow down C# if I do it) for (int k = i + p; k < end; k += p) { primes\[k\] = 0; } } } }#else
WORD end = 8193;
char primes[8193];
while (NUM-- != 0)
{
for (WORD i = 0; i < end; i++)
primes[i] = 1;for (WORD i = 2; i < end; ++i) if (primes\[i\] != 0) for (WORD k = 2 \* i; k < end; k += i) primes\[k\] = 0; }#endif
DWORD dw2 = ::GetTickCount(); std::cout << "Milliseconds = " << dw2-dw << std::endl; return 0;}
====================================== C# ======================================
unsafe static void Main(string[] args)
{
if (args.Length != 1)
{
Console.WriteLine("Usage:\tsieve [iterations]");
return;
}int NUM = int.Parse(args\[0\]); var t0 = DateTime.Now; int end = 8193; var primes = stackalloc byte\[end\]; while (NUM-- != 0) { for (int i = 0; i < end; i++) primes\[i\] = 1; for (int i = 2; i < end; ++i) if (primes\[i\] != 0) for (int k = 2 \* i; k < end; k += i) primes\[k\] = 0; } var dt = DateTime.Now - t0; System.Console.WriteLine("Milliseconds = {0}", dt.TotalMilliseconds);}
====================================== F# ======================================
open System
[<EntryPoint>]
let main args =let NUM = Int32.Parse args.\[0\] let t0 = DateTime.Now let primes : byte\[\] = Array.zeroCreate ( 8192 + 1 ) let aend = 8192 for nloop = 1 to NUM do for i = 0 to aend do primes.\[i\] <- 1uy for i = 2 to aend do if primes.\[i\] <> 0uy then let mutable k = 2 \* i while k <= aend do primes.\[k\] <- 0uy k <- k + i let dt = DateTime.Now - t0 Console.WriteLine("Milliseconds = {0}", dt.TotalMilliseconds) 0===============================
Cool. I'm looking at it now. I'll post back in a bit.
Simon
-
indeed, but they had this propaganda that .NET is JIT compiled just for the machine it's running on, so that theoretically it can even be faster! (it's what they used to say) Further C# 4 is way faster and this algorithm is so simple I can hardly see why the JITted version couldn't be as good as the compiled C version... guess I was wrong.. guess when things are looped over a huge number of time, just 1 instruction can make a big difference....
A train station is where the train stops. A bus station is where the bus stops. On my desk, I have a work station.... _________________________________________________________ My programs never have bugs, they just develop random features.
Super Lloyd wrote:
indeed, but they had this propaganda that .NET is JIT compiled just for the machine it's running on, so that theoretically it can even be faster!
I guess this happens also for
C++, in this case. :)If the Lord God Almighty had consulted me before embarking upon the Creation, I would have recommended something simpler. -- Alfonso the Wise, 13th Century King of Castile.
This is going on my arrogant assumptions. You may have a superb reason why I'm completely wrong. -- Iain Clarke
[My articles] -
Super Lloyd wrote:
indeed, but they had this propaganda that .NET is JIT compiled just for the machine it's running on, so that theoretically it can even be faster!
I guess this happens also for
C++, in this case. :)If the Lord God Almighty had consulted me before embarking upon the Creation, I would have recommended something simpler. -- Alfonso the Wise, 13th Century King of Castile.
This is going on my arrogant assumptions. You may have a superb reason why I'm completely wrong. -- Iain Clarke
[My articles]Mmm... indeed! Silly me! :laugh:
A train station is where the train stops. A bus station is where the bus stops. On my desk, I have a work station.... _________________________________________________________ My programs never have bugs, they just develop random features.
-
Super Lloyd wrote:
how do I get the disassembly of the JITted code?!
Like I said, throw an uncaught exception. Attach the debugger when it is thrown. To prevent certain optimizations, ensure that throwing the exceptions happens at a place that the compiler can't prove will be reached. Then open the disassembly view. (doesn't exist in express editions)
Cool, I have both assembly version side by side now! :) Mm.. the C++ has much short loop! (I mean much less assembly instruction in the loop) :~ Now trying to read the ASM closely and guess what went "wrong" in the C# version...
A train station is where the train stops. A bus station is where the bus stops. On my desk, I have a work station.... _________________________________________________________ My programs never have bugs, they just develop random features.
-
Cool. I'm looking at it now. I'll post back in a bit.
Simon
yes, do post back please! :P
A train station is where the train stops. A bus station is where the bus stops. On my desk, I have a work station.... _________________________________________________________ My programs never have bugs, they just develop random features.
-
Cool, I have both assembly version side by side now! :) Mm.. the C++ has much short loop! (I mean much less assembly instruction in the loop) :~ Now trying to read the ASM closely and guess what went "wrong" in the C# version...
A train station is where the train stops. A bus station is where the bus stops. On my desk, I have a work station.... _________________________________________________________ My programs never have bugs, they just develop random features.
-
Super Lloyd wrote:
any C# performance tip is welcome!
That is like looking for performance from Java: You won't get it. If you need (or want) performance, don't do retards' languages. I know this thread isn't meant to incite hatred against retards' languages.
NULL
Mechanical wrote:
That is like looking for performance from Java: You won't get it.
You are horribly wrong here. In some cases, C# can outperform C/C++ performance-wise. And that is because of the optimizations that can be made at intermediate-level i.e, IL or bytecode or whatever (which people like you think might be the reason for slowness). See here for a performance comparison between different languages[^] However, if you like to follow the sheep, go ahead.
-
C++ ======================================
int _tmain(int argc, _TCHAR* argv[])
{
if (argc != 2)
{
std::cerr << "Usage:\tsieve [iterations]\n";
return 1;
};size\_t NUM = \_wtoi(argv\[1\]); DWORD dw = ::GetTickCount();#if ! CS-Speed
char primes[8192+1];
int pbegin = 0;
int begin = 2;
int end = 8193;while (NUM -- != 0) { for (int i = 0; i < end; i++) { primes\[i\] = 1; } for (int i = begin; i < end; ++i) { if (primes\[i\] != 0) { int p = i; // using this extra variable speeds up C++!!! (and slow down C# if I do it) for (int k = i + p; k < end; k += p) { primes\[k\] = 0; } } } }#else
WORD end = 8193;
char primes[8193];
while (NUM-- != 0)
{
for (WORD i = 0; i < end; i++)
primes[i] = 1;for (WORD i = 2; i < end; ++i) if (primes\[i\] != 0) for (WORD k = 2 \* i; k < end; k += i) primes\[k\] = 0; }#endif
DWORD dw2 = ::GetTickCount(); std::cout << "Milliseconds = " << dw2-dw << std::endl; return 0;}
====================================== C# ======================================
unsafe static void Main(string[] args)
{
if (args.Length != 1)
{
Console.WriteLine("Usage:\tsieve [iterations]");
return;
}int NUM = int.Parse(args\[0\]); var t0 = DateTime.Now; int end = 8193; var primes = stackalloc byte\[end\]; while (NUM-- != 0) { for (int i = 0; i < end; i++) primes\[i\] = 1; for (int i = 2; i < end; ++i) if (primes\[i\] != 0) for (int k = 2 \* i; k < end; k += i) primes\[k\] = 0; } var dt = DateTime.Now - t0; System.Console.WriteLine("Milliseconds = {0}", dt.TotalMilliseconds);}
====================================== F# ======================================
open System
[<EntryPoint>]
let main args =let NUM = Int32.Parse args.\[0\] let t0 = DateTime.Now let primes : byte\[\] = Array.zeroCreate ( 8192 + 1 ) let aend = 8192 for nloop = 1 to NUM do for i = 0 to aend do primes.\[i\] <- 1uy for i = 2 to aend do if primes.\[i\] <> 0uy then let mutable k = 2 \* i while k <= aend do primes.\[k\] <- 0uy k <- k + i let dt = DateTime.Now - t0 Console.WriteLine("Milliseconds = {0}", dt.TotalMilliseconds) 0===============================
Nothing to do with the optimisation, but what about using the StopWatch class instead of datetime? Start the stop watch immediately before you enter the loop, and then stop it as soon as the loop exists.
Dave Find Me On: Web|Facebook|Twitter|LinkedIn CPRepWatcher now available as Packaged Chrome Extension, visit my articles for link.
-
Mechanical wrote:
That is like looking for performance from Java: You won't get it.
You are horribly wrong here. In some cases, C# can outperform C/C++ performance-wise. And that is because of the optimizations that can be made at intermediate-level i.e, IL or bytecode or whatever (which people like you think might be the reason for slowness). See here for a performance comparison between different languages[^] However, if you like to follow the sheep, go ahead.
-
I have a short program which check prime number. Run multiple time a single slow loop, to test performance. I have a C++, C# and F# version. (to be fair with C# the C++ version use fixed sized 32 bit integers, instead of native size int, but that doesn't seem to make a difference anyway) A few things puzzle me. 1. The c++ is definitely faster! my best C# tweak makes C++ 20% faster. That surprises me because C# is compiled too (at runtime, at the first run) and I am only looping over byte array and using int number, I am not doing interop, and even I use stackalloc and pointer in (unsafe) C# so there is no bound check. And the algorithm is so simple that it's hard to believe (but it must be true) that the C++ compiler optimize the generated code further than the JITted C# one... 2. creating an array with stackalloc result in faster loop (5%) than using fixed(&array[0]), in fact using fixed(&array[0]) has the same speed than using normal (safe and bound checked) array!! how come!?! 3. F# is 25% slower than C#. Well I guess I should not be too surprised and I guess that teach me the posts about amazing performance of F# have less to do with some "magic F# quality" and more to do with the heavy type inference / use of generic and "fast delegate" replacement, which is not really put to use in my sample. So, what is the question? err.. Well, any C# performance tip is welcome!
A train station is where the train stops. A bus station is where the bus stops. On my desk, I have a work station.... _________________________________________________________ My programs never have bugs, they just develop random features.
Super Lloyd wrote:
Well, any C# performance tip is welcome!
Uncle John's Handy C# Performance Tip #237: Convert the code to unmanaged C++.
.45 ACP - because shooting twice is just silly
-----
"Why don't you tie a kerosene-soaked rag around your ankles so the ants won't climb up and eat your candy ass..." - Dale Earnhardt, 1997
-----
"The staggering layers of obscenity in your statement make it a work of art on so many levels." - J. Jystad, 2001 -
Mechanical wrote:
That is like looking for performance from Java: You won't get it.
You are horribly wrong here. In some cases, C# can outperform C/C++ performance-wise. And that is because of the optimizations that can be made at intermediate-level i.e, IL or bytecode or whatever (which people like you think might be the reason for slowness). See here for a performance comparison between different languages[^] However, if you like to follow the sheep, go ahead.
Aamir Butt wrote:
In some cases, C# can outperform C/C++
How about ALL cases ? People who talk about C# (or any other retards' language) performance are talking about void while engaged with other C# (or any other retards' language) performance addicts in group masturbation. The link in your post points to another post by a C# guru (read as: VB guru). It says: "Remember : Engineers are expensive and servers are not!". Look at that! I mean just look at how pathetic that retard is.
Aamir Butt wrote:
However, if you like to follow the sheep, go ahead.
I'll bet you are one of those that believe Java is the future of 3D.
NULL
-
I already posted the source code: http://www.codeproject.com/Lounge.aspx?msg=3657380#xx3657380xx[^] As to the disassembly, err.... well, ok, but I have to cut the C++ version as it huge loads of stuff coming the #include(s), hopefully I'll cut it right ... disassembled JITted C#
--- C:\Dev\Test\Performance\CSperf\Program.cs ----------------------------------
if (args.Length != 1)
00000000 push ebp
00000001 mov ebp,esp
00000003 push edi
00000004 push esi
00000005 sub esp,6Ch
00000008 mov esi,ecx
0000000a lea edi,[ebp-74h]
0000000d mov ecx,1Bh
00000012 xor eax,eax
00000014 rep stos dword ptr es:[edi]
00000016 mov ecx,esi
00000018 mov dword ptr [ebp-0Ch],esp
0000001b mov dword ptr [ebp-74h],2941BF9Bh
00000022 mov dword ptr [ebp-60h],ecx
00000025 cmp dword ptr ds:[001B7CB8h],0
0000002c je 00000033
0000002e call 62889E21
00000033 xor edx,edx
00000035 mov dword ptr [ebp-28h],edx
00000038 xor edx,edx
0000003a mov dword ptr [ebp-1Ch],edx
0000003d xor edx,edx
0000003f mov dword ptr [ebp-24h],edx
00000042 xor edx,edx
00000044 mov dword ptr [ebp-2Ch],edx
00000047 xor edx,edx
00000049 mov dword ptr [ebp-20h],edx
0000004c xor edx,edx
0000004e mov dword ptr [ebp-10h],edx
00000051 mov eax,dword ptr [ebp-60h]
00000054 cmp dword ptr [eax+4],1
00000058 je 0000006B
{
Console.WriteLine("Usage:\tsieve [iterations]");
0000005a mov ecx,dword ptr ds:[03832088h]
00000060 call 62202DB4
return;
00000065 nop
00000066 jmp 0000019A
}int NUM = int.Parse(args\[0\]);0000006b mov eax,dword ptr [ebp-60h]
0000006e cmp dword ptr [eax+4],0
00000072 ja 00000079
00000074 call 6288BA5C
00000079 mov ecx,dword ptr [eax+0Ch]
0000007c call 6220EAC4
00000081 mov dword ptr [ebp-38h],eax
00000084 mov eax,dword ptr [ebp-38h]
00000087 mov dword ptr [ebp-10h],eax
var t0 = DateTime.Now;
0000008a lea ecx,[ebp-40h]
0000008d call 61D07768 -
Super Lloyd wrote:
Well, any C# performance tip is welcome!
Uncle John's Handy C# Performance Tip #237: Convert the code to unmanaged C++.
.45 ACP - because shooting twice is just silly
-----
"Why don't you tie a kerosene-soaked rag around your ankles so the ants won't climb up and eat your candy ass..." - Dale Earnhardt, 1997
-----
"The staggering layers of obscenity in your statement make it a work of art on so many levels." - J. Jystad, 2001:-D
5.If the Lord God Almighty had consulted me before embarking upon the Creation, I would have recommended something simpler. -- Alfonso the Wise, 13th Century King of Castile.
This is going on my arrogant assumptions. You may have a superb reason why I'm completely wrong. -- Iain Clarke
[My articles] -
I already posted the source code: http://www.codeproject.com/Lounge.aspx?msg=3657380#xx3657380xx[^] As to the disassembly, err.... well, ok, but I have to cut the C++ version as it huge loads of stuff coming the #include(s), hopefully I'll cut it right ... disassembled JITted C#
--- C:\Dev\Test\Performance\CSperf\Program.cs ----------------------------------
if (args.Length != 1)
00000000 push ebp
00000001 mov ebp,esp
00000003 push edi
00000004 push esi
00000005 sub esp,6Ch
00000008 mov esi,ecx
0000000a lea edi,[ebp-74h]
0000000d mov ecx,1Bh
00000012 xor eax,eax
00000014 rep stos dword ptr es:[edi]
00000016 mov ecx,esi
00000018 mov dword ptr [ebp-0Ch],esp
0000001b mov dword ptr [ebp-74h],2941BF9Bh
00000022 mov dword ptr [ebp-60h],ecx
00000025 cmp dword ptr ds:[001B7CB8h],0
0000002c je 00000033
0000002e call 62889E21
00000033 xor edx,edx
00000035 mov dword ptr [ebp-28h],edx
00000038 xor edx,edx
0000003a mov dword ptr [ebp-1Ch],edx
0000003d xor edx,edx
0000003f mov dword ptr [ebp-24h],edx
00000042 xor edx,edx
00000044 mov dword ptr [ebp-2Ch],edx
00000047 xor edx,edx
00000049 mov dword ptr [ebp-20h],edx
0000004c xor edx,edx
0000004e mov dword ptr [ebp-10h],edx
00000051 mov eax,dword ptr [ebp-60h]
00000054 cmp dword ptr [eax+4],1
00000058 je 0000006B
{
Console.WriteLine("Usage:\tsieve [iterations]");
0000005a mov ecx,dword ptr ds:[03832088h]
00000060 call 62202DB4
return;
00000065 nop
00000066 jmp 0000019A
}int NUM = int.Parse(args\[0\]);0000006b mov eax,dword ptr [ebp-60h]
0000006e cmp dword ptr [eax+4],0
00000072 ja 00000079
00000074 call 6288BA5C
00000079 mov ecx,dword ptr [eax+0Ch]
0000007c call 6220EAC4
00000081 mov dword ptr [ebp-38h],eax
00000084 mov eax,dword ptr [ebp-38h]
00000087 mov dword ptr [ebp-10h],eax
var t0 = DateTime.Now;
0000008a lea ecx,[ebp-40h]
0000008d call 61D07768 -
Super Lloyd wrote:
Well, any C# performance tip is welcome!
Uncle John's Handy C# Performance Tip #237: Convert the code to unmanaged C++.
.45 ACP - because shooting twice is just silly
-----
"Why don't you tie a kerosene-soaked rag around your ankles so the ants won't climb up and eat your candy ass..." - Dale Earnhardt, 1997
-----
"The staggering layers of obscenity in your statement make it a work of art on so many levels." - J. Jystad, 2001Well it's only tip #237, so I guess it's not the 1st thing I should rush to do! :)
A train station is where the train stops. A bus station is where the bus stops. On my desk, I have a work station.... _________________________________________________________ My programs never have bugs, they just develop random features.
-
Super Lloyd wrote:
any C# performance tip is welcome!
That is like looking for performance from Java: You won't get it. If you need (or want) performance, don't do retards' languages. I know this thread isn't meant to incite hatred against retards' languages.
NULL
Mechanical, I checked your profile. You've never authored an article, posted a snippet, entered a blog post, or otherwise shared any original thought, except to snipe at other people's comments on the message boards. In other words, you have yet to provide any empirical evidence for your worth to this site. No be a good boy and go away, please.
-
My statement was made because I had to maintain some Native code I wrote some years ago. I realized how retarded I had become doing retards' languages.
peterchen wrote:
Are you open to evidence for my statement
I'm all ears (big, pointy ears).
NULL
The Raymond Chen vs. Rico Mariani competition comes to mind. Clickety[^] Clickety-Click[^] The final result, at first look, supports your statement: The C++ version completed before the .NET application even did load. However, when you look at the history and details, you see that the road to the superfast C++ application was a rocky one, introducing subtle bugs and requiring a very experienced developer to counter the rather simple improvements to the C# solution.
With extensions like LINQ, Closures, Lambdas, Generics and some syntactic sugar, C# has become a rather complex and powerful language. It's complex and powerful in a different sense than C++, but still.
Agh! Reality! My Archnemesis![^]
| FoldWithUs! | sighist | WhoIncludes - Analyzing C++ include file hierarchymodified on Friday, November 5, 2010 11:17 AM
-
Well it's only tip #237, so I guess it's not the 1st thing I should rush to do! :)
A train station is where the train stops. A bus station is where the bus stops. On my desk, I have a work station.... _________________________________________________________ My programs never have bugs, they just develop random features.
Hey! Take stop reading my mind!
Agh! Reality! My Archnemesis![^]
| FoldWithUs! | sighist | WhoIncludes - Analyzing C++ include file hierarchy -
Nothing to do with the optimisation, but what about using the StopWatch class instead of datetime? Start the stop watch immediately before you enter the loop, and then stop it as soon as the loop exists.
Dave Find Me On: Web|Facebook|Twitter|LinkedIn CPRepWatcher now available as Packaged Chrome Extension, visit my articles for link.
I agree. On my machine 10 iterations take 0.5 milliseconds, which DateTime.Now can't catch at all. :)
Luc Pattyn [Forum Guidelines] [Why QA sucks] [My Articles] Nil Volentibus Arduum
Please use <PRE> tags for code snippets, they preserve indentation, and improve readability.
-
I already posted the source code: http://www.codeproject.com/Lounge.aspx?msg=3657380#xx3657380xx[^] As to the disassembly, err.... well, ok, but I have to cut the C++ version as it huge loads of stuff coming the #include(s), hopefully I'll cut it right ... disassembled JITted C#
--- C:\Dev\Test\Performance\CSperf\Program.cs ----------------------------------
if (args.Length != 1)
00000000 push ebp
00000001 mov ebp,esp
00000003 push edi
00000004 push esi
00000005 sub esp,6Ch
00000008 mov esi,ecx
0000000a lea edi,[ebp-74h]
0000000d mov ecx,1Bh
00000012 xor eax,eax
00000014 rep stos dword ptr es:[edi]
00000016 mov ecx,esi
00000018 mov dword ptr [ebp-0Ch],esp
0000001b mov dword ptr [ebp-74h],2941BF9Bh
00000022 mov dword ptr [ebp-60h],ecx
00000025 cmp dword ptr ds:[001B7CB8h],0
0000002c je 00000033
0000002e call 62889E21
00000033 xor edx,edx
00000035 mov dword ptr [ebp-28h],edx
00000038 xor edx,edx
0000003a mov dword ptr [ebp-1Ch],edx
0000003d xor edx,edx
0000003f mov dword ptr [ebp-24h],edx
00000042 xor edx,edx
00000044 mov dword ptr [ebp-2Ch],edx
00000047 xor edx,edx
00000049 mov dword ptr [ebp-20h],edx
0000004c xor edx,edx
0000004e mov dword ptr [ebp-10h],edx
00000051 mov eax,dword ptr [ebp-60h]
00000054 cmp dword ptr [eax+4],1
00000058 je 0000006B
{
Console.WriteLine("Usage:\tsieve [iterations]");
0000005a mov ecx,dword ptr ds:[03832088h]
00000060 call 62202DB4
return;
00000065 nop
00000066 jmp 0000019A
}int NUM = int.Parse(args\[0\]);0000006b mov eax,dword ptr [ebp-60h]
0000006e cmp dword ptr [eax+4],0
00000072 ja 00000079
00000074 call 6288BA5C
00000079 mov ecx,dword ptr [eax+0Ch]
0000007c call 6220EAC4
00000081 mov dword ptr [ebp-38h],eax
00000084 mov eax,dword ptr [ebp-38h]
00000087 mov dword ptr [ebp-10h],eax
var t0 = DateTime.Now;
0000008a lea ecx,[ebp-40h]
0000008d call 61D07768You need to be careful, the JIT will turn off optimizations when running inside the Visual Studio debugger (even in release builds!). To get the optimized JITted assembly code, you need to run your program from the command line, then attach the debugger to the running process, and click Break.
