Cost of calling a standard library function

From: The Half A Wannabee ("The)
Date: 02/28/04 

Date: Sat, 28 Feb 2004 07:38:38 +0100

Code is given below. As you can see from the timings, calling the "Standard
library" routine is almost twice as slow as writing it yourself. And the
funny thing is, the straight, no mind, forward written RosAsm code, I wrote
*first*...performs best. This is the same code that Randall Hyde commented a
week back or so, that it was inefficient. Assume nothing. Even when Randall
speaks, be critical. Code is written in RosAsm.
http://betov.free.fr/RosAsm.html

Who would have guessed that Rep Movsd would be the slowest of them all ? It
is 20000 ticks SLOWER than the Windows API !! My plain "stupid" approach is
57282 ticks faster than this. 2X !
Yes, we push/pop esi and edi, but this is needed in real life ! "Nobody"
copies the same sourcerect to the same destinationrect 1_000_000 times,
unless for non productive test code like this. But as the results show, this
time the testcode is useful. At least on this machine. Test Machine is an
AMD 1800+ running at 1000 Mhz. (It was "cheap". Only I cant run it on
fullspeed, as it gets to warm..so how cheap is that )?

Start 1_000_000 calls to CopyRect :014 014
TimeStamp result___________________ :054287 054273
Start 1_000_000 calls to CopyRect_2 :054290 003
TimeStamp result___________________ :123789 069499
Start 1_000_000 calls to CopyRect_3 :123793 004
TimeStamp result___________________ :235348 111555
Start 1_000_000 calls to Win32 API :235352 004
TimeStamp result___________________ :319786 084434

CODE :

;Parameters are pointers to rectangles
Proc CopyRect:
 Arguments @DestRect @SourceRect
  mov eax D@SourceRect
  mov edx D@DestRect
  ;left
  mov ebx D$eax + TRect_Left | mov D$edx + TRect_Left ebx
  ;top
  mov ebx D$eax + TRect_Top | mov D$edx + TRect_Top ebx
  ;right
  mov ebx D$eax + TRect_Right | mov D$edx + TRect_Right ebx
  ;bottom
  mov ebx D$eax + TRect_Bottom | mov D$edx + TRect_Bottom ebx
EndP

;Parameters are pointers to rectangles
Proc CopyRect2:
 Arguments @DestRect @SourceRect

  mov eax D@SourceRect
  mov edx D@DestRect
  PushRect D$eax
  PopRect D$edx
EndP

;Parameters are pointers to rectangles
Proc CopyRect3:
 Arguments @DestRect @SourceRect

  push edi esi
     mov esi D@SourceRect
     mov edi D@DestRect
     mov ecx 4
     rep movsd
  pop edi edi
EndP

;Above is the homebrew routines that gets tested, below is the test code.
Only the part we test are included. To get hold of the full sourcecode for
the (not yet completed) performance counter, take a look at theese two
links. Source code is included in the exefile, within the zip archive. Load
it into the RosAsm assmebler IDE using File/load to view the code. Hover the
mouse just below the menu to see the TITLE's navigator. Click on the one
thats says PerformanceCounter to see the full PerformanceCounter code.

http://www.szmyggenpv.com/downloads/FontSupport.Zip

http://www.szmyggenpv.com/downloads/Documentation.Zip

[TestCopyRect1:'Start 1_000_000 calls to CopyRect :' 0]
[TestCopyRect2:'Start 1_000_000 calls to CopyRect_2 :' 0]
[TestCopyRect3:'Start 1_000_000 calls to CopyRect_3 :' 0]
[TestCopyRect4:'Start 1_000_000 calls to Win32 API :' 0]
[TestRemark2: 'TimeStamp result___________________ :' 0]
TPerformanceCounter_SelfTest:
  Push edi

    mov D$WindowUtilDirectoryFlags 1
    call WindowUtil_OleSupport_Start

    call TPerformanceCounter_Create | mov D$PerformanceCounter edi
    call TPerformanceCounter_Start

    ;Test 3 version of the CopyRect function

    call TPerformanceCounter_TimeStampRemark TestCopyRect1
    mov ecx 1_000_000
    @TestPerformance:
    push ecx
       call CopyRect ARect BRect
    pop ecx
    dec ecx
    jnz @TestPerformance
    call TPerformanceCounter_TimeStampRemark TestRemark2

    call TPerformanceCounter_TimeStampRemark TestCopyRect2
    mov ecx 1_000_000
    @TestPerformance1:
    push ecx
       call CopyRect2 ARect BRect
    pop ecx
    dec ecx
    jnz @TestPerformance1
    call TPerformanceCounter_TimeStampRemark TestRemark2

    call TPerformanceCounter_TimeStampRemark TestCopyRect3
    mov ecx 1_000_000
    @TestPerformance2:
    push ecx
       call CopyRect2 ARect BRect
    pop ecx
    dec ecx
    jnz @TestPerformance2
    call TPerformanceCounter_TimeStampRemark TestRemark2

    call TPerformanceCounter_TimeStampRemark TestCopyRect4
    mov ecx 1_000_000
    @TestPerformance3:
    push ecx
       call 'user32.CopyRect' ARect BRect
    pop ecx
    dec ecx
    jnz @TestPerformance3
    call TPerformanceCounter_TimeStampRemark TestRemark2

    call TPerformanceCounter_Stop &FALSE

    push edi esi
      mov eax D$gDesktopDir
        push eax
         call FileManager_ComposeFullFileNameEAX D$eax + TString_Pchar
PerformanceFileName
           push eax
            Call TPerformanceCounter_SaveToTextFile D$eax + TString_Pchar
           pop eax
         call StringManager_DisposeString
        pop eax
      call StringManager_DisposeString
    pop esi edi

    Call TPerformanceCounter_Destroy

    call WindowUtil_OleSupport_Shutdown
  pop edi
  ;call TSkinSection_SetDisabled
  call TSZSkinWindow_RepaintWindow
ret
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