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I am thinking about developing Winforms application that would use c library to preform all computations. I want to use C# because developing GUI with it is really easy, and C to increase performance. Are there other advantages or any disadvantages of combining those two languages?

Edit: As computations I mean mainly (but not limited to) graph algorithms, like coloring, dijakstra, maximum flow; I expect graphs to be huge, and performance is really crucial.

Zaphood
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    C# has quite good performance, in most cases comparable to C. Why do you Think you need both ? – driis Oct 14 '11 at 22:24
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    We can't possibly answer this question without understanding what "computations" you want to perform. But I feel pretty confident this rationale is totally misconceived. C# is jitted and runs extremely fast. You should prove that your "computations" are indeed performance critical (and moreover, will be helped by being written in C) before embarking down this path. – Kirk Woll Oct 14 '11 at 22:24
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    Make sure that C is actually going to be faster for you. Poorly written C is slower than well written C#. For that matter, poorly written (insert fast language here) is usually slower than well written (insert slow language here). Code quality is a crucial factor when looking at speed. – riwalk Oct 14 '11 at 22:25
  • As computations I mean mainly but not limited to graph algorithms, like coloring, dijakstra, maximum flow; I expect graphs to be huge, and performance is really crucial. And i don't expect to lose code quality in C :) – Zaphood Oct 14 '11 at 22:41

4 Answers4

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and C to increase performance

You could write pretty well performing applications using pure managed code. Take for example this very same site. It's pretty darn fast, don't you think?

The way I see things is the following: mix those two technologies only if you are really some kind of a performance maniac (someone that tries to solve the scaling problems that Google does for example) or if you have some existing C codebase that you cannot port to .NET immediately and that you have to interoperate with.

In other cases, managed code is safer. If you are sick about performance don't forget that in many cases the cost of marshaling between managed and unmanaged code will be higher than the performance you would gain from pure unmanaged code. Also the JITter gets smarter and smarter with each version of the framework and maybe one day it will generate almost as efficient code as unmanaged code.

So, yeah, go for managed and leave C to the maniacs :-)

Darin Dimitrov
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  • i have had this argument before but I hit 'C# is a scripting language for slow stuff, real code is written in C/C++' – pm100 Mar 05 '14 at 18:55
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I would not be so sure that C will be faster than C# for what you are going to do. The jitted code is extremely fast. Also, if you are doing lots of calculations, by using c#/.net, you could potentially take advantage of the Task Parallel Library, which would greatly ease parallelizing your calculations. And really, with all of the multi-core machines, I think that you will get a lot more bang for your bucks if you can take advantage of multiple cores (of course, straight C can thread as well, but the TPL in .net 4 is much more productive than the base WinApi)

One other thing that you might consider, and I am speaking from outside of my own experience, so definitely do your own research: I have heard that F# can be a very good choice for writing scientific sets/calculation libraries. I haven't written a line of F# myself, but from what I understand, the language design supports writing the calculations in a way that makes them extremely parallelizable.

(of course, now you have a new problem -- learning F# ;)

there is a post here that you might check out: F# performance in scientific computing

Community
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JMarsch
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  • I 've checked out F# - mayby it could help indeed, but time of learning and writing algorithms in it is too much unpredictible :P – Zaphood Oct 15 '11 at 22:27
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Getting fixed memory locations, and also converting your indexes to C pointers could have negative side effects. You can try both safe and unsafe code for sure and try to see the results but my guess is that safe code will perform better at the end. For sure, your computation is also important factor.

Yagiz Ozturk
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I have done this in the past, I would say that as other mentioned the cost of marshalling is not free so you need some pretty specialised need before this is a valid option.

My only advice to you would be to start in the most adapted language, which would be C# if you want to have managed code and other features that C# provide. And then if performance is an issue and do some profiling and optimise carefully by adding some code in C after weighting the pro/cons and considering whether you can get some optimisation by reworking the high level algorithm rather than optimising at a lower level.

For example, if you were to write scientific code, you would make your code multithreadable or checking that you cannot reuse previous computations before to attempt other kind of lower level optimisation, this will have a much larger impact on your efficiency rather than chasing tiny problems.

BlueTrin
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