Question

I am using CultureInfo.CurrentCulture when formating my strings using string.format

To quote this blog

This just has the implication that if
you are using CurrentCulture a lot, it
might be worth reading it into a
private variable rather than making
lots of calls to
CultureInfo.CurrentCulture, otherwise
you’re using up clock cycles
needlessly.

so as per this author

var culture = CultureInfo.CurrentCulture
string.Format(culture,"{0} some format string","some args");
string.Format(culture,"{0} some format string","some other args");

is better than

string.Format(CultureInfo.CurrentCulture,"{0} some format string","some args");
string.Format(CultureInfo.CurrentCulture,"{0} some format string","some other args");

as per MSDN, CultureInfo.CurrentCulture is a property

Is there a performance penalty associated when accessing a property multiple times ??

Also I did some emperical analysis and my tests show me that using a local variable is more expensive than using the property directly.

Stopwatch watch = new Stopwatch();

            int count = 100000000;
            watch.Start();
            for(int i=0;i<count;i++)
            {
                string.Format(CultureInfo.CurrentCulture, "{0} is my name", "ram");
            }


            watch.Stop();
                 //EDIT:Reset watch
                 watch.Reset();


            Console.WriteLine(watch.Elapsed);
            Console.WriteLine(watch.ElapsedMilliseconds);
            Console.WriteLine(watch.ElapsedTicks);


            Console.WriteLine("--------------------");
            var culture = CultureInfo.CurrentCulture;
            watch.Start();
            for (int i=0; i < count; i++)
            {
                string.Format(culture, "{0} is my name", "ram");
            }


            watch.Stop();

            Console.WriteLine(watch.Elapsed);
            Console.WriteLine(watch.ElapsedMilliseconds);
            Console.WriteLine(watch.ElapsedTicks);

Result:

00:00:29.6116306
29611
68922550970
--------------------
00:00:27.3578116
27357
63676674390

My tests show that using CultureInfo.CurrentCulture property is better than using local variable (which contradicts with the authors view). Or am I missing something here ?

Edit:I was not resetting the stopwatch before teh second iteration. hence the difference. resetting stopwatch, updating iteration count and result in this edit

Answer 1

There is a bug in your code. In your test code you don’t reset the Stopwatch. When you reset the stop watch, you’ll see that using the cached reference is actually faster. CultureInfo.CurrentCulture isn’t cheap, but string.Format is much more costlier.