Vista - clr and jit

06-04-2008

What is the difference in definition between clr and jit compiler? Does the
use of jit make .NET an interpreted language, or is it still a compiled
language, or both?

Daniel

06-04-2008

Hello Daniel,

Read there

http://en.wikipedia.org/wiki/Just-in-time_compilation
http://en.wikipedia.org/wiki/Common_Language_Runtime

---
WBR,
Michael Nemtsev [.NET/C# MVP] :: blog: http://spaces.live.com/laflour

"The greatest danger for most of us is not that our aim is too high and we
miss it, but that it is too low and we reach it" (c) Michelangelo

D> What is the difference in definition between clr and jit compiler?
D> Does the use of jit make .NET an interpreted language, or is it still
D> a compiled language, or both?
D>
D> Daniel
D>

06-05-2008

Daniel <Mahonri@xxxxxx> wrote:

Quote:

> What is the difference in definition between clr and jit compiler?

The JIT compiler is just one small part of the CLR.

Quote:

> Does the use of jit make .NET an interpreted language, or is it still
> a compiled language, or both?

The code is never interpreted in .NET - always JIT compiled and then
executed natively (with support from the CLR, of course).

--
Jon Skeet - <skeet@xxxxxx>
Web site: http://www.pobox.com/~skeet
Blog: http://www.msmvps.com/jon.skeet
C# in Depth: http://csharpindepth.com

07-06-2008

"Jon Skeet [C# MVP]" <skeet@xxxxxx> wrote in message
news:MPG.22b241bbc4f93330d41@xxxxxx

Quote:

> Daniel <Mahonri@xxxxxx> wrote:

Quote:

>> What is the difference in definition between clr and jit compiler?

>
> The JIT compiler is just one small part of the CLR.
>

Quote:

>> Does the use of jit make .NET an interpreted language, or is it still
>> a compiled language, or both?

>
> The code is never interpreted in .NET - always JIT compiled and then
> executed natively (with support from the CLR, of course).

Which occasionally is a performance-killing mistake.

For example, a type initializer. Is there ever an advantage to optimizing
the .cctor? Anything I can think of that could need optimization (anonymous
methods, expression trees, etc) has already been separated by the compiler
before any MSIL is generated.

Quote:

>
> --
> Jon Skeet - <skeet@xxxxxx>
> Web site: http://www.pobox.com/~skeet
> Blog: http://www.msmvps.com/jon.skeet
> C# in Depth: http://csharpindepth.com

07-07-2008

Hello Ben,

Quote:

>> The code is never interpreted in .NET - always JIT compiled and then
>> executed natively (with support from the CLR, of course).
>>

> Which occasionally is a performance-killing mistake.
> For example, a type initializer. Is there ever an advantage to
> optimizing the .cctor? Anything I can think of that could need
> optimization (anonymous methods, expression trees, etc) has already
> been separated by the compiler before any MSIL is generated.

If you care about performance -- use NGEN utility from .NET SDK. It produces
native code from your assebmly instead of IL.

Thanks,
Andrei

07-07-2008

Ben Voigt [C++ MVP] <rbv@xxxxxx> wrote:

Quote:

> >> Does the use of jit make .NET an interpreted language, or is it still
> >> a compiled language, or both?

> >
> > The code is never interpreted in .NET - always JIT compiled and then
> > executed natively (with support from the CLR, of course).

>
> Which occasionally is a performance-killing mistake.
>
> For example, a type initializer. Is there ever an advantage to optimizing
> the .cctor? Anything I can think of that could need optimization (anonymous
> methods, expression trees, etc) has already been separated by the compiler
> before any MSIL is generated.

Likewise the initialization code for most forms is often executed only
once. I believe that Sun's HotSpot JIT will interpret code the first
time it runs, unless it spots significant loops. The benefit of the
"always JIT, and JIT exactly once" solution is that it's much simpler
than the kind of optimisation HotSpot performs. But yes, there can be a
price to pay.

--
Jon Skeet - <skeet@xxxxxx>
Web site: http://www.pobox.com/~skeet
Blog: http://www.msmvps.com/jon_skeet
C# in Depth: http://csharpindepth.com

06-04-2008	#1
Daniel n/a posts	clr and jit What is the difference in definition between clr and jit compiler? Does the use of jit make .NET an interpreted language, or is it still a compiled language, or both? Daniel
My System Specs

06-04-2008	#2
Michael Nemtsev [MVP] n/a posts	Re: clr and jit Hello Daniel, Read there http://en.wikipedia.org/wiki/Just-in-time_compilation http://en.wikipedia.org/wiki/Common_Language_Runtime --- WBR, Michael Nemtsev [.NET/C# MVP] :: blog: http://spaces.live.com/laflour "The greatest danger for most of us is not that our aim is too high and we miss it, but that it is too low and we reach it" (c) Michelangelo D> What is the difference in definition between clr and jit compiler? D> Does the use of jit make .NET an interpreted language, or is it still D> a compiled language, or both? D> D> Daniel D>
My System Specs

06-05-2008	#3
Jon Skeet [C# MVP] n/a posts	Re: clr and jit Daniel <Mahonri@xxxxxx> wrote: Quote: > What is the difference in definition between clr and jit compiler? The JIT compiler is just one small part of the CLR. Quote: > Does the use of jit make .NET an interpreted language, or is it still > a compiled language, or both? The code is never interpreted in .NET - always JIT compiled and then executed natively (with support from the CLR, of course). -- Jon Skeet - <skeet@xxxxxx> Web site: http://www.pobox.com/~skeet Blog: http://www.msmvps.com/jon.skeet C# in Depth: http://csharpindepth.com
My System Specs

07-06-2008	#4
Ben Voigt [C++ MVP] n/a posts	Re: clr and jit "Jon Skeet [C# MVP]" <skeet@xxxxxx> wrote in message news:MPG.22b241bbc4f93330d41@xxxxxx Quote: > Daniel <Mahonri@xxxxxx> wrote: Quote: >> What is the difference in definition between clr and jit compiler? > > The JIT compiler is just one small part of the CLR. > Quote: >> Does the use of jit make .NET an interpreted language, or is it still >> a compiled language, or both? > > The code is never interpreted in .NET - always JIT compiled and then > executed natively (with support from the CLR, of course). Which occasionally is a performance-killing mistake. For example, a type initializer. Is there ever an advantage to optimizing the .cctor? Anything I can think of that could need optimization (anonymous methods, expression trees, etc) has already been separated by the compiler before any MSIL is generated. Quote: > > -- > Jon Skeet - <skeet@xxxxxx> > Web site: http://www.pobox.com/~skeet > Blog: http://www.msmvps.com/jon.skeet > C# in Depth: http://csharpindepth.com
My System Specs

07-07-2008	#5
Andrei Varanovich [C# MVP] n/a posts	Re: clr and jit Hello Ben, Quote: Quote: >> The code is never interpreted in .NET - always JIT compiled and then >> executed natively (with support from the CLR, of course). >> > Which occasionally is a performance-killing mistake. > For example, a type initializer. Is there ever an advantage to > optimizing the .cctor? Anything I can think of that could need > optimization (anonymous methods, expression trees, etc) has already > been separated by the compiler before any MSIL is generated. If you care about performance -- use NGEN utility from .NET SDK. It produces native code from your assebmly instead of IL. Thanks, Andrei
My System Specs

07-07-2008	#6
Jon Skeet [C# MVP] n/a posts	Re: clr and jit Ben Voigt [C++ MVP] <rbv@xxxxxx> wrote: Quote: Quote: Quote: > >> Does the use of jit make .NET an interpreted language, or is it still > >> a compiled language, or both? > > > > The code is never interpreted in .NET - always JIT compiled and then > > executed natively (with support from the CLR, of course). > > Which occasionally is a performance-killing mistake. > > For example, a type initializer. Is there ever an advantage to optimizing > the .cctor? Anything I can think of that could need optimization (anonymous > methods, expression trees, etc) has already been separated by the compiler > before any MSIL is generated. Likewise the initialization code for most forms is often executed only once. I believe that Sun's HotSpot JIT will interpret code the first time it runs, unless it spots significant loops. The benefit of the "always JIT, and JIT exactly once" solution is that it's much simpler than the kind of optimisation HotSpot performs. But yes, there can be a price to pay. -- Jon Skeet - <skeet@xxxxxx> Web site: http://www.pobox.com/~skeet Blog: http://www.msmvps.com/jon_skeet C# in Depth: http://csharpindepth.com
My System Specs