Has anyone done any performance testing between new generic Lists and single
dimensional arrays?
I really like the code flexibility the List provides since I don't know how
many items I will have in the list. With my array approach, I have to
manage re-sizing the array myself.
So, is using List<myClass> x as fast as MyClass[] x ?
11  14521 
Hello, ZenRhapsody!
List<myClass> x, internally will use myClass[] array;
So, the overhead of using List<T> is not big
However, you may not like List<T> memory allocation strategy ( allocation uses doubling algorithm - when enlarging list size it uses "this._items.Le ngth * 2" )
--
Regards, Vadym Stetsyak
www: http://vadmyst.blogspot.com
"ZenRhapsod y" <no****@hotmail .com> wrote in message
news:eA******** ******@TK2MSFTN GP11.phx.gbl...
Has anyone done any performance testing between new generic Lists and
single dimensional arrays?
I really like the code flexibility the List provides since I don't know
how many items I will have in the list. With my array approach, I have to
manage re-sizing the array myself.
So, is using List<myClass> x as fast as MyClass[] x ?
Why do you care?
Either it is fast enough for your needs - in which case you should use it
because it makes the code easier to write and maintain - or it isn't - in
which case you are in big trouble and writing your own probably will not
give you enough to save you.
I assume that you are not required to properly test your code or you
wouldn't even ask this question.
Hi,
Take a look at http://msmvps.com/blogs/jon.skeet/ar...reachperf.aspx it's
a comparision of the different ways to traverse a list.
--
Ignacio Machin,
ignacio.machin AT dot.state.fl.us
Florida Department Of Transportation
"ZenRhapsod y" <no****@hotmail .com> wrote in message
news:eA******** ******@TK2MSFTN GP11.phx.gbl...
Has anyone done any performance testing between new generic Lists and
single dimensional arrays?
I really like the code flexibility the List provides since I don't know
how many items I will have in the list. With my array approach, I have to
manage re-sizing the array myself.
So, is using List<myClass> x as fast as MyClass[] x ?
To those of you with useful respones - thanks.
With small test cases, I have found today that the generic List to be
considerably
slower (> than 20%) IF you can get the initial size large enough - it's
comparable to faster if
many resizes are required. Of course, my tests are not optimized with
unsafe code blocks to limit subscript checking when manually resizing
arrays.
I'm still using C# express (company hasn't fully jumped to 2.0 yet),
and I know my debugging and optimization options are limited here. If I
could see the optimized assembly, I'd feel better with the results.
If any MSFT folks know where future optimizations are planned, that'd be
useful too.
Yo Nick, this is a professional forum for professionals who want to give each
other professional advice. Take your attitude elsewhere. You're wasting
people's precious time. Prick.
"Nick Hounsome" wrote:
"ZenRhapsod y" <no****@hotmail .com> wrote in message
news:eA******** ******@TK2MSFTN GP11.phx.gbl...
Has anyone done any performance testing between new generic Lists and
single dimensional arrays?
I really like the code flexibility the List provides since I don't know
how many items I will have in the list. With my array approach, I have to
manage re-sizing the array myself.
So, is using List<myClass> x as fast as MyClass[] x ?
Why do you care?
Either it is fast enough for your needs - in which case you should use it
because it makes the code easier to write and maintain - or it isn't - in
which case you are in big trouble and writing your own probably will not
give you enough to save you.
I assume that you are not required to properly test your code or you
wouldn't even ask this question.
Hi,
I agree with Michael, yours is not the best of the attitude, or at least
the tone of the answer does not seems nice to me.
You do have a point though, that sometimes the best code is not the fastest
, but sometimes it;s
OP: in addition to the other post I recommended you before read this http://www.interact-sw.co.uk/iangblo...1/09/profiling , it's a post by
Ian Griffiths titled "Profilers and The Perils of Micro-Optimization"
--
Ignacio Machin,
ignacio.machin AT dot.state.fl.us
Florida Department Of Transportation
"Nick Hounsome" <nh***@nickhoun some.me.uk> wrote in message
news:B1******** **********@fe3. news.blueyonder .co.uk...
"ZenRhapsod y" <no****@hotmail .com> wrote in message
news:eA******** ******@TK2MSFTN GP11.phx.gbl...
Has anyone done any performance testing between new generic Lists and
single dimensional arrays?
I really like the code flexibility the List provides since I don't know
how many items I will have in the list. With my array approach, I have
to manage re-sizing the array myself.
So, is using List<myClass> x as fast as MyClass[] x ?
Why do you care?
Either it is fast enough for your needs - in which case you should use it
because it makes the code easier to write and maintain - or it isn't - in
which case you are in big trouble and writing your own probably will not
give you enough to save you.
I assume that you are not required to properly test your code or you
wouldn't even ask this question.
It all depends on how your testing and if you size the list as big as the
test array from the beginning. If you look at the list, it resizes in
basically the same way you would do it yourself with an Array.Copy into a
larger array.
--
William Stacey [MVP]
"ZenRhapsod y" <no****@hotmail .com> wrote in message
news:uL******** ******@TK2MSFTN GP10.phx.gbl...
| To those of you with useful respones - thanks.
|
| With small test cases, I have found today that the generic List to be
| considerably
| slower (> than 20%) IF you can get the initial size large enough - it's
| comparable to faster if
| many resizes are required. Of course, my tests are not optimized with
| unsafe code blocks to limit subscript checking when manually resizing
| arrays.
|
| I'm still using C# express (company hasn't fully jumped to 2.0 yet),
| and I know my debugging and optimization options are limited here. If I
| could see the optimized assembly, I'd feel better with the results.
|
| If any MSFT folks know where future optimizations are planned, that'd be
| useful too.
|
|
Since your definition of a professional discussion seems to include personal
insults I can only assume that I am being too polite for you.
I professionally adise you not to swear at people.
"Michael" <Mi*****@discus sions.microsoft .com> wrote in message
news:1B******** *************** ***********@mic rosoft.com... Yo Nick, this is a professional forum for professionals who want to give
each
other professional advice. Take your attitude elsewhere. You're wasting
people's precious time. Prick.
"Nick Hounsome" wrote:
"ZenRhapsod y" <no****@hotmail .com> wrote in message
news:eA******** ******@TK2MSFTN GP11.phx.gbl... >
> Has anyone done any performance testing between new generic Lists and
> single dimensional arrays?
>
> I really like the code flexibility the List provides since I don't
> know
> how many items I will have in the list. With my array approach, I have
> to
> manage re-sizing the array myself.
>
> So, is using List<myClass> x as fast as MyClass[] x ?
Why do you care?
Either it is fast enough for your needs - in which case you should use it
because it makes the code easier to write and maintain - or it isn't - in
which case you are in big trouble and writing your own probably will not
give you enough to save you.
I assume that you are not required to properly test your code or you
wouldn't even ask this question.
"Ignacio Machin ( .NET/ C# MVP )" <ignacio.mach in AT dot.state.fl.us > wrote
in message news:OH******** *******@TK2MSFT NGP14.phx.gbl.. . Hi,
I agree with Michael, yours is not the best of the attitude, or at least
the tone of the answer does not seems nice to me.
Do you mean my entirely serious and in no way abusive questioning of the OPs
motivation for looking to avoid standard classes for very low level
performance improvements?
You do have a point though, that sometimes the best code is not the
fastest , but sometimes it;s
Which is why you need to know the motivation and circumstances.
The best balance of performance and code complexity cannot be known without
having at least some idea what the actual requirements are.
In my experience in 80% of cases there is no need to make any performance
enhancement whatsoever. In 15% of cases the soultion is better algorithms at
a higher level and in the remaining 5% of cases the most cost effective
soloution is usually to require a more powerful computer to run on (It works
for Microsoft).
--
Ignacio Machin,
ignacio.machin AT dot.state.fl.us
Florida Department Of Transportation
"Nick Hounsome" <nh***@nickhoun some.me.uk> wrote in message
news:B1******** **********@fe3. news.blueyonder .co.uk...
"ZenRhapsod y" <no****@hotmail .com> wrote in message
news:eA******** ******@TK2MSFTN GP11.phx.gbl...
Has anyone done any performance testing between new generic Lists and
single dimensional arrays?
I really like the code flexibility the List provides since I don't know
how many items I will have in the list. With my array approach, I have
to manage re-sizing the array myself.
So, is using List<myClass> x as fast as MyClass[] x ?
Why do you care?
Either it is fast enough for your needs - in which case you should use it
because it makes the code easier to write and maintain - or it isn't - in
which case you are in big trouble and writing your own probably will not
give you enough to save you.
I assume that you are not required to properly test your code or you
wouldn't even ask this question.
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