Unexpected performance
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With
const int COUNT = 10000000;
myClass** objects = new myClass*[COUNT];(heap because of stackoverflow) I got 3582 native and 1612 with /clr
Greetings - Gajatko Portable.NET is part of DotGNU, a project to build a complete Free Software replacement for .NET - a system that truly belongs to the developers.
gajatko wrote:
I got 3582 native and 1612 with /clr
Which numbers are you reporting there? Mark
Mark Salsbery Microsoft MVP - Visual C++ :java:
-
gajatko wrote:
I got 3582 native and 1612 with /clr
Which numbers are you reporting there? Mark
Mark Salsbery Microsoft MVP - Visual C++ :java:
start = clock();
for (int i = 0; i < COUNT; i++) {
objects[i] = new myClass();
delete objects[i];
}
printf("Native with delete: %f\n", (double)(clock() - start) / CLOCKS_PER_SEC * 1000);Greetings - Gajatko Portable.NET is part of DotGNU, a project to build a complete Free Software replacement for .NET - a system that truly belongs to the developers.
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start = clock();
for (int i = 0; i < COUNT; i++) {
objects[i] = new myClass();
delete objects[i];
}
printf("Native with delete: %f\n", (double)(clock() - start) / CLOCKS_PER_SEC * 1000);Greetings - Gajatko Portable.NET is part of DotGNU, a project to build a complete Free Software replacement for .NET - a system that truly belongs to the developers.
Try this (and do NOT run in the debugger!)
class myClass
{
};int _tmain(int argc, _TCHAR* argv[])
{
const int COUNT = 1000000;
myClass** objects = new myClass*[COUNT];clock\_t start1 = clock(); for (int i = 0; i < COUNT; i++) { objects\[i\] = new myClass(); delete objects\[i\]; } clock\_t end1 = clock(); clock\_t start2 = clock(); for (int i = 0; i < COUNT; i++){ objects\[i\] = new myClass(); } clock\_t end2 = clock(); clock\_t start3 = clock(); for (int i = 0; i < COUNT; i++){ delete objects\[i\]; } clock\_t end3 = clock(); printf("Loop with new/delete: %d\\n\\n", end1 - start1); printf("Loop with new: %d\\n", end2 - start2); printf("Loop with delete: %d\\n", end3 - start3); printf("Total of loop new and loop delete: %d\\n", end3 - start2); printf("\\n\\nPress enter to end..."); getchar(); delete\[\] objects; return 0;}
Mark Salsbery Microsoft MVP - Visual C++ :java:
-
Try this (and do NOT run in the debugger!)
class myClass
{
};int _tmain(int argc, _TCHAR* argv[])
{
const int COUNT = 1000000;
myClass** objects = new myClass*[COUNT];clock\_t start1 = clock(); for (int i = 0; i < COUNT; i++) { objects\[i\] = new myClass(); delete objects\[i\]; } clock\_t end1 = clock(); clock\_t start2 = clock(); for (int i = 0; i < COUNT; i++){ objects\[i\] = new myClass(); } clock\_t end2 = clock(); clock\_t start3 = clock(); for (int i = 0; i < COUNT; i++){ delete objects\[i\]; } clock\_t end3 = clock(); printf("Loop with new/delete: %d\\n\\n", end1 - start1); printf("Loop with new: %d\\n", end2 - start2); printf("Loop with delete: %d\\n", end3 - start3); printf("Total of loop new and loop delete: %d\\n", end3 - start2); printf("\\n\\nPress enter to end..."); getchar(); delete\[\] objects; return 0;}
Mark Salsbery Microsoft MVP - Visual C++ :java:
-
Mark Salsbery wrote:
Try this (and do NOT run in the debugger!)
Did you look something like this[^] while typing that in?
led mike
LMAO! You betcha! :laugh:
Mark Salsbery Microsoft MVP - Visual C++ :java:
-
Try this (and do NOT run in the debugger!)
class myClass
{
};int _tmain(int argc, _TCHAR* argv[])
{
const int COUNT = 1000000;
myClass** objects = new myClass*[COUNT];clock\_t start1 = clock(); for (int i = 0; i < COUNT; i++) { objects\[i\] = new myClass(); delete objects\[i\]; } clock\_t end1 = clock(); clock\_t start2 = clock(); for (int i = 0; i < COUNT; i++){ objects\[i\] = new myClass(); } clock\_t end2 = clock(); clock\_t start3 = clock(); for (int i = 0; i < COUNT; i++){ delete objects\[i\]; } clock\_t end3 = clock(); printf("Loop with new/delete: %d\\n\\n", end1 - start1); printf("Loop with new: %d\\n", end2 - start2); printf("Loop with delete: %d\\n", end3 - start3); printf("Total of loop new and loop delete: %d\\n", end3 - start2); printf("\\n\\nPress enter to end..."); getchar(); delete\[\] objects; return 0;}
Mark Salsbery Microsoft MVP - Visual C++ :java:
OK so what should I see? I get results: For /clr:
Loop with new/delete: 174
Loop with new: 101
Loop with delete: 77
Total of loop new and loop delete: 178Press enter to end...
for not /clr:
Loop with new/delete: 306
Loop with new: 90
Loop with delete: 64
Total of loop new and loop delete: 154Press enter to end...
And I neither run from IDE nor in Debug mode. According to a "you pay as you go" C++ philosophy the result should be the same.
Greetings - Gajatko Portable.NET is part of DotGNU, a project to build a complete Free Software replacement for .NET - a system that truly belongs to the developers.
-
Mark Salsbery wrote:
Try this (and do NOT run in the debugger!)
Did you look something like this[^] while typing that in?
led mike
Good one! Personally I get used to strange things happening with M$ implementation of Java VM*, so I look like this constantly when programming. Uhm something wrong with logic is here but who cares. Cheers :-D * - ok, just kidding.
Greetings - Gajatko Portable.NET is part of DotGNU, a project to build a complete Free Software replacement for .NET - a system that truly belongs to the developers.
-
Any ideas why the following code runs faster (19 vs 37 msec in the first test) with
/clrflag on? No clr is used in the code at all!#include "stdafx.h"
class myClass
{
};int main()
{
clock_t start;
const int COUNT = 100000;
myClass* objects[COUNT];
start = clock();
for (int i = 0; i < COUNT; i++) {
objects[i] = new myClass();
delete objects[i];
}
printf("Native with delete: %f\n", (double)(clock() - start));start = clock(); for (int i = 0; i < COUNT; i++){ objects\[i\] = new myClass(); } clock\_t start2 = clock(); for (int i = 0; i < COUNT; i++){ delete objects\[i\]; } printf("Native without delete: %f\\n", (double)(start2 - start)); printf("Deletion: %f\\n", (double)(clock() - start2)); printf("Total: %f\\n", (double)(clock() - start));}
Greetings - Gajatko Portable.NET is part of DotGNU, a project to build a complete Free Software replacement for .NET - a system that truly belongs to the developers.
I'm not sure what you're expecting here. First, if you were running tests in the debugger, forgetaboutit. Second, comparing times for two sets of loops isn't going to work. Try putting the loop with the new/delete combined below the other two loops and you'll see what I mean. There's alot going on with the heap there, making the results...well, there's no comparison. Third, comparing native to CLR build...the MSIL is better optimized than the debug native code (assuming that's what you were comparing to). Again, no comparison. I would guess, if you figure out the right combination of optimization switches, you MAY be able to make the native version a TINY bit faster than the managed version...maybe... Lastly, don't believe people that say managed code is slower :)
Mark Salsbery Microsoft MVP - Visual C++ :java:
-
OK so what should I see? I get results: For /clr:
Loop with new/delete: 174
Loop with new: 101
Loop with delete: 77
Total of loop new and loop delete: 178Press enter to end...
for not /clr:
Loop with new/delete: 306
Loop with new: 90
Loop with delete: 64
Total of loop new and loop delete: 154Press enter to end...
And I neither run from IDE nor in Debug mode. According to a "you pay as you go" C++ philosophy the result should be the same.
Greetings - Gajatko Portable.NET is part of DotGNU, a project to build a complete Free Software replacement for .NET - a system that truly belongs to the developers.
Mark Salsbery Microsoft MVP - Visual C++ :java:
-
OK so what should I see? I get results: For /clr:
Loop with new/delete: 174
Loop with new: 101
Loop with delete: 77
Total of loop new and loop delete: 178Press enter to end...
for not /clr:
Loop with new/delete: 306
Loop with new: 90
Loop with delete: 64
Total of loop new and loop delete: 154Press enter to end...
And I neither run from IDE nor in Debug mode. According to a "you pay as you go" C++ philosophy the result should be the same.
Greetings - Gajatko Portable.NET is part of DotGNU, a project to build a complete Free Software replacement for .NET - a system that truly belongs to the developers.
By the way, just curious - what's your test platform (CPU(s)/speed) and compiler version?
Mark Salsbery Microsoft MVP - Visual C++ :java:
-
By the way, just curious - what's your test platform (CPU(s)/speed) and compiler version?
Mark Salsbery Microsoft MVP - Visual C++ :java:
-
Good one! Personally I get used to strange things happening with M$ implementation of Java VM*, so I look like this constantly when programming. Uhm something wrong with logic is here but who cares. Cheers :-D * - ok, just kidding.
Greetings - Gajatko Portable.NET is part of DotGNU, a project to build a complete Free Software replacement for .NET - a system that truly belongs to the developers.
-
By the way, just curious - what's your test platform (CPU(s)/speed) and compiler version?
Mark Salsbery Microsoft MVP - Visual C++ :java:
Vista B. x64 SP 1 Intel Quad 2.4, 2 GB RAM, VS 2008
Greetings - Gajatko Portable.NET is part of DotGNU, a project to build a complete Free Software replacement for .NET - a system that truly belongs to the developers.
-
I'm not sure what you're expecting here. First, if you were running tests in the debugger, forgetaboutit. Second, comparing times for two sets of loops isn't going to work. Try putting the loop with the new/delete combined below the other two loops and you'll see what I mean. There's alot going on with the heap there, making the results...well, there's no comparison. Third, comparing native to CLR build...the MSIL is better optimized than the debug native code (assuming that's what you were comparing to). Again, no comparison. I would guess, if you figure out the right combination of optimization switches, you MAY be able to make the native version a TINY bit faster than the managed version...maybe... Lastly, don't believe people that say managed code is slower :)
Mark Salsbery Microsoft MVP - Visual C++ :java:
Mark Salsbery wrote:
I'm not sure what you're expecting here.
Not sure what to expect, but definately not this (sounds good).
Mark Salsbery wrote:
First, if you were running tests in the debugger, forgetaboutit.
Hey, I'm not an urgent-codes-plz-gimme-guy and I do not do tests in a debugger!!
Mark Salsbery wrote:
Second, comparing times for two sets of loops isn't going to work.
That was secondary tests. In fact, the first one was important to me (ok, not important. All this talk is neither interesting nor important, but I must figure the thing out).
Mark Salsbery wrote:
the MSIL is better optimized
What could be optimized in such a simple code?
Mark Salsbery wrote:
Lastly, don't believe people that say managed code is slower
Lucky and happy you. The problem is that if you believe something (God, Holy Grail, etc.) you likely believe people as well. Oh sorry I'm getting too soap-boxy.
Greetings - Gajatko Portable.NET is part of DotGNU, a project to build a complete Free Software replacement for .NET - a system that truly belongs to the developers.
-
Mark Salsbery wrote:
I'm not sure what you're expecting here.
Not sure what to expect, but definately not this (sounds good).
Mark Salsbery wrote:
First, if you were running tests in the debugger, forgetaboutit.
Hey, I'm not an urgent-codes-plz-gimme-guy and I do not do tests in a debugger!!
Mark Salsbery wrote:
Second, comparing times for two sets of loops isn't going to work.
That was secondary tests. In fact, the first one was important to me (ok, not important. All this talk is neither interesting nor important, but I must figure the thing out).
Mark Salsbery wrote:
the MSIL is better optimized
What could be optimized in such a simple code?
Mark Salsbery wrote:
Lastly, don't believe people that say managed code is slower
Lucky and happy you. The problem is that if you believe something (God, Holy Grail, etc.) you likely believe people as well. Oh sorry I'm getting too soap-boxy.
Greetings - Gajatko Portable.NET is part of DotGNU, a project to build a complete Free Software replacement for .NET - a system that truly belongs to the developers.
gajatko wrote:
Not sure what to expect, but definately not this
Definitely didn't expect what?
gajatko wrote:
Lucky and happy you.
I have no idea what you mean by that. I didn't state anything about me.
gajatko wrote:
The problem is that if you believe something (God, Holy Grail, etc.) you likely believe people as well.
Not sure what that means either. Just because I believe I'll have another beer doesn't mean I believe people.
Mark Salsbery Microsoft MVP - Visual C++ :java:
-
gajatko wrote:
Not sure what to expect, but definately not this
Definitely didn't expect what?
gajatko wrote:
Lucky and happy you.
I have no idea what you mean by that. I didn't state anything about me.
gajatko wrote:
The problem is that if you believe something (God, Holy Grail, etc.) you likely believe people as well.
Not sure what that means either. Just because I believe I'll have another beer doesn't mean I believe people.
Mark Salsbery Microsoft MVP - Visual C++ :java:
It looks like I reached a maximum humour abstraction level last night. Do not take that serious please. :-O :rolleyes:
Greetings - Gajatko Portable.NET is part of DotGNU, a project to build a complete Free Software replacement for .NET - a system that truly belongs to the developers.
-
It looks like I reached a maximum humour abstraction level last night. Do not take that serious please. :-O :rolleyes:
Greetings - Gajatko Portable.NET is part of DotGNU, a project to build a complete Free Software replacement for .NET - a system that truly belongs to the developers.
No problem :) Cheers :beer:
Mark Salsbery Microsoft MVP - Visual C++ :java:
-
I'm not sure what you're expecting here. First, if you were running tests in the debugger, forgetaboutit. Second, comparing times for two sets of loops isn't going to work. Try putting the loop with the new/delete combined below the other two loops and you'll see what I mean. There's alot going on with the heap there, making the results...well, there's no comparison. Third, comparing native to CLR build...the MSIL is better optimized than the debug native code (assuming that's what you were comparing to). Again, no comparison. I would guess, if you figure out the right combination of optimization switches, you MAY be able to make the native version a TINY bit faster than the managed version...maybe... Lastly, don't believe people that say managed code is slower :)
Mark Salsbery Microsoft MVP - Visual C++ :java:
Mark Salsbery wrote:
Lastly, don't believe people that say managed code is slower
Actually...this is exactly what we're finding. Real world problem: - MFC application, 1 EXE and 5 DLL's. The DLL's do all the computations and are highly optimized C++ code which have been validated for correctness and operation many times in the past decade. And we have spent many late nights finding performance gains - the code is good. The front-end is GUI. We have MFC, STL, ATL technologies incorporated, plus a lot of hand-written code - because STL was too slow. The DLL's implement linear algebra, various geometry calculations, and 1st-order PDE's. There are also simple array/table look-ups. The project is 300,000+ lines code. - we also use ZLIB, GDAL/OGR, CGAL but they aren't used in these tests Test results: - baseline is current release build, test case taks 190seconds. - simply turn on the /clr switch on as many files as possible (following the bouncing ball, trying to do it right) and performance drops to 345 seconds (not all could run managed because of MFC) - retest native release build, it stays the same - concerned we are doing too many native/managed swaps to translate 1 DLL to entirely a C++/CLI classlib, performance drops to 355 seconds. Confused so try it again, 361 seconds - try NGEN on the classlib, performance becomes 349 seconds - try NGEN on the entire project, performance becomes 476 seconds! - back out of changes, start over with the native release build, back around 188 seconds - incorporate the classlib and do MINIMUM required to get things to link back together (to use native as much as possible) and performance is around 244 seconds All other test cases yield similar results. We WANT to move to .Net (to clean up the code, make it easier to maintain and read, etc.), but we need a migratory path where we don't have to rewrite the entire front end out of MFC right away. But these performance #'s just suck. We can't ask the client to live with such poor performance during migration in hopes it will improve when it's all done and running strictly in managed. We have experience with C# in another project but are new in the C++/CLI world. I'd happily discuss this online or offline but 'til then I can't agree with your comment at all Mark! --Rob
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Mark Salsbery wrote:
Lastly, don't believe people that say managed code is slower
Actually...this is exactly what we're finding. Real world problem: - MFC application, 1 EXE and 5 DLL's. The DLL's do all the computations and are highly optimized C++ code which have been validated for correctness and operation many times in the past decade. And we have spent many late nights finding performance gains - the code is good. The front-end is GUI. We have MFC, STL, ATL technologies incorporated, plus a lot of hand-written code - because STL was too slow. The DLL's implement linear algebra, various geometry calculations, and 1st-order PDE's. There are also simple array/table look-ups. The project is 300,000+ lines code. - we also use ZLIB, GDAL/OGR, CGAL but they aren't used in these tests Test results: - baseline is current release build, test case taks 190seconds. - simply turn on the /clr switch on as many files as possible (following the bouncing ball, trying to do it right) and performance drops to 345 seconds (not all could run managed because of MFC) - retest native release build, it stays the same - concerned we are doing too many native/managed swaps to translate 1 DLL to entirely a C++/CLI classlib, performance drops to 355 seconds. Confused so try it again, 361 seconds - try NGEN on the classlib, performance becomes 349 seconds - try NGEN on the entire project, performance becomes 476 seconds! - back out of changes, start over with the native release build, back around 188 seconds - incorporate the classlib and do MINIMUM required to get things to link back together (to use native as much as possible) and performance is around 244 seconds All other test cases yield similar results. We WANT to move to .Net (to clean up the code, make it easier to maintain and read, etc.), but we need a migratory path where we don't have to rewrite the entire front end out of MFC right away. But these performance #'s just suck. We can't ask the client to live with such poor performance during migration in hopes it will improve when it's all done and running strictly in managed. We have experience with C# in another project but are new in the C++/CLI world. I'd happily discuss this online or offline but 'til then I can't agree with your comment at all Mark! --Rob
Hi Rob, My comment was in the context of the OP. I challenged the OP to optimize his sample to be as fast or faster than the managed version. I also implied he couldn't do it :) Of course highly optimized C++ code is going to be faster - faster than ANY high level language. That's its purpose.
Rob Bryce wrote:
simply turn on the /clr switch on as many files as possible
I certainly wouldn't do that. C++/CLI is meant to be a bridge from native C++ to the managed .NET world. It should be used as that. Use the #pragma managed/#pragma unmanaged macros to control what code gets compiled managed and what stays native. Then you can keep your optimized or performance critical code compiled native. This can be done at the function level! :) Cheers, Mark
Mark Salsbery Microsoft MVP - Visual C++ :java:
