Hi,
Numbers are things that can convince me.:)
Now I have three questions:
- Are there parts of the patch that are OK to commit?
- Do we care about class signature (what methods are overriden)?
- Do we care about the implementation of virtual methods (what methods do
they call)?
I can follow any guidelines - altough I don't belive in performance above
everything else - but I would like to know them otherwise I cannot follow
them.
Kornél
----- Original Message -----
From: "Atsushi Eno" <[EMAIL PROTECTED]>
To: "Kornél Pál" <[EMAIL PROTECTED]>
Cc: <mono-devel-list@lists.ximian.com>
Sent: Tuesday, April 11, 2006 6:56 PM
Subject: Re: [Mono-dev] [PATCH] Add GetString to UnicodeEncoding 2.0
andmodifysome Encoding wrappers
Hi,
I'm not interested in how your patch accomplishes MS.NET compatibility.
My question is simple: is your patch *good* for Mono?
using System;
using System.Diagnostics;
using System.IO;
using System.Text;
public class Test
{
public static void Main (string [] args)
{
int loop = args.Length > 1 ? int.Parse (args [1]) : 100;
string s = File.OpenText (args [0]).ReadToEnd ();
Encoding e = Encoding.Unicode;
Stopwatch sw = Stopwatch.StartNew ();
for (int i = 0; i < loop; i++)
e.GetBytes (s);
sw.Stop ();
Console.WriteLine (sw.ElapsedMilliseconds);
}
}
Before your patch:
mono ./unicode.exe ../../svn/mono/web/web/masterinfos/System.Web.xml
5038
After the patch:
$ rundev2 mono ./unicode.exe
../../svn/mono/web/web/masterinfos/System.Web.xml
10175
Atsushi Eno
Kornél Pál wrote:
Hi,
I had some time and looked at all the encoding classes in I18N and in
System.Text.
byte* and char* is only used in UnicodeEncoding and GetByteCount and
GetBytes in I18N.
This means that having the #if NET_2_0 codes that you don't want to
remove will cause performance loss on profile 2.0 in System.Text while
will not improve performance in profile 1.1 as no such optimization is
done.
The solution is to use arrays in Encoding that improves simple, old
fashioned encoding classes but override these methods to use pointers in
classes that implement their core functionality using unsafe code.
Encodings in System.Text (except UnicodeEncoding) use arrays and I think
custom encodings created by users are array based as well so it results
in better performance if we use arrays in Encoding. If custom encodings
are using unsafe code they will have to override other methods because of
MS.NET anyway to get the performance improvement.
By overriding GetByteCount (string) and GetBytes (string) in MonoEncoding
performance improvement on unsafe code will be preserved in addition it
will be available in all profiles.
MonoEncoding was already good so I just added these two methods and added
the following code to GetBytes methods:
int byteCount = bytes.Length - byteIndex;
if (bytes.Length == 0)
bytes = new byte [1];
Some check is required because &bytes[0] will fail for zero-size arrays.
"bytes.Length == byteIndex" could avoid this (but was present in only one
of the methods) but this would prevent ArgumentException being thrown for
too small output buffers. Creating a small array is little overhead and
an exception will probably be thrown because charCount is non-zero.
Attached an improved patch. Please review the patch.
Kornél
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