Timing anomalies.

[hutch--]

This was a simple test on a task to count ascii 13 in a text file to try and improve the speed of a tokeniser. I did not get any real improvement in the second version but found a weird anomaly in the timing method. I put the 2 algos into library modules to try and normalise the timings but found the timings at least as quirky as having the code locally in the main module. I tried a simple experiment of changing the order of the two prototypes and produced 2 different sets of timings.

With the 2 prototypes in this order,

    cr_cnt2 PROTO :DWORD
    cr_cnt PROTO :DWORD

I get this timings between the two algos.

889 ms 1
843 ms 2
874 ms 1
827 ms 2
874 ms 1
827 ms 2
874 ms 1
843 ms 2
Press any key to continue ...


Change the order to,

    cr_cnt PROTO :DWORD
    cr_cnt2 PROTO :DWORD

And you get this timing.

1076 ms 1
842 ms 2
1076 ms 1
843 ms 2
1077 ms 1
842 ms 2
1076 ms 1
826 ms 2
Press any key to continue ...

[dedndave]

that makes no sense at all - something else must be different between the 2 runs

[dedndave]

crashes right away under xp-32

[dedndave]

even so.....

you should be able to change the order of the prototypes and create the exact same EXE
compare the 2 EXE's - shouldn't be any difference

[hutch--]

Dave,

Just rebuild the code on XP then run it. The test piece on my Win7 64 was built with ML version 9.0, I just copied the entire directory to an XP box, rebuilt it with ML 6.14 and it worked correctly.

[dedndave]

ok....

looks like the assembler pulls them in in the order prototyped
the old "code location sensitivity" issue - good to be aware of   

Code Select Expand

Comparing files cz1.exe and CZ2.EXE
000000C8: 96 CF
000001C0: 42 4A
00000464: B8 68
00000465: 03 02
000004B1: 1B 4B
000006E2: 0F 74
000006E3: 84 06
000006E4: 27 85
000006E5: 01 D2
000006E6: 00 75
000006E7: 00 F1
000006E8: 85 EB
000006E9: D2 05
000006EA: 0F 83
000006EB: 84 C0
000006EC: 27 01
000006ED: 01 EB
000006EE: 00 EA
000006EF: 00 C2
000006F0: 83 04
000006F1: C1 00
000006F2: 01 CC
000006F3: 0F CC
000006F4: B6 CC
000006F5: 11 CC
000006F6: 83 CC
000006F7: FA CC
000006F8: 0D CC
000006F9: 0F CC
000006FA: 84 CC
000006FB: 10 CC
000006FC: 01 CC
000006FD: 00 CC
000006FE: 00 CC
000006FF: 85 CC
00000700: D2 8B
00000701: 0F 4C
00000702: 84 24
00000703: 10 04
00000704: 01 33
00000705: 00 C0
00000706: 00 83
00000707: 83 E9
00000708: C1 01
00000709: 01 83
0000070A: 0F C1
0000070B: B6 01
0000070C: 11 0F
0000070D: 83 B6
0000070E: FA 11
0000070F: 0D 83
00000710: 0F FA
00000711: 84 0D
00000712: F9 0F
00000713: 00 84
00000714: 00 27
00000715: 00 01
00000716: 85 00
00000717: D2 00
00000718: 0F 85
00000719: 84 D2
0000071A: F9 0F
0000071B: 00 84
0000071C: 00 27
0000071D: 00 01
0000071E: 83 00
0000071F: C1 00
00000720: 01 83
00000721: 0F C1
00000722: B6 01
00000723: 11 0F
00000724: 83 B6
00000725: FA 11
00000726: 0D 83
00000727: 0F FA
00000728: 84 0D
00000729: E2 0F
0000072A: 00 84
0000072B: 00 10
0000072C: 00 01
0000072D: 85 00
0000072E: D2 00
0000072F: 0F 85
00000730: 84 D2
00000731: E2 0F
00000732: 00 84
00000733: 00 10
00000734: 00 01
00000735: 83 00
00000736: C1 00
00000737: 01 83
00000738: 0F C1
00000739: B6 01
0000073A: 11 0F
0000073B: 83 B6
0000073C: FA 11
0000073D: 0D 83
0000073E: 0F FA
0000073F: 84 0D
00000740: CB 0F
00000741: 00 84
00000742: 00 F9
00000744: 85 00
00000745: D2 00
00000746: 0F 85
00000747: 84 D2
00000748: CB 0F
00000749: 00 84
0000074A: 00 F9
0000074C: 83 00
0000074D: C1 00
0000074E: 01 83
0000074F: 0F C1
00000750: B6 01
00000751: 11 0F
00000752: 83 B6
00000753: FA 11
00000754: 0D 83
00000755: 0F FA
00000756: 84 0D
00000757: B4 0F
00000758: 00 84
00000759: 00 E2
0000075B: 85 00
0000075C: D2 00
0000075D: 0F 85
0000075E: 84 D2
0000075F: B4 0F
00000760: 00 84
00000761: 00 E2
00000763: 83 00
00000764: C1 00
00000765: 01 83
00000766: 0F C1
00000767: B6 01
00000768: 11 0F
00000769: 83 B6
0000076A: FA 11
0000076B: 0D 83
0000076C: 0F FA
0000076D: 84 0D
0000076E: 9D 0F
0000076F: 00 84
00000770: 00 CB
00000772: 85 00
00000773: D2 00
00000774: 0F 85
00000775: 84 D2
00000776: 9D 0F
00000777: 00 84
00000778: 00 CB
0000077A: 83 00
0000077B: C1 00
0000077C: 01 83
0000077D: 0F C1
0000077E: B6 01
0000077F: 11 0F
00000780: 83 B6
00000781: FA 11
00000782: 0D 83
00000783: 0F FA
00000784: 84 0D
00000785: 86 0F
00000786: 00 84
00000787: 00 B4
00000789: 85 00
0000078A: D2 00
0000078B: 0F 85
0000078C: 84 D2
0000078D: 86 0F
0000078E: 00 84
0000078F: 00 B4
00000791: 83 00
00000792: C1 00
00000793: 01 83
00000794: 0F C1
00000795: B6 01
00000796: 11 0F
00000797: 83 B6
00000798: FA 11
00000799: 0D 83
0000079A: 74 FA
0000079B: 73 0D
0000079C: 85 0F
0000079D: D2 84
0000079E: 74 9D
0000079F: 77 00
000007A0: 83 00
000007A1: C1 00
000007A2: 01 85
000007A3: 0F D2
000007A4: B6 0F
000007A5: 11 84
000007A6: 83 9D
000007A7: FA 00
000007A8: 0D 00
000007A9: 74 00
000007AA: 64 83
000007AB: 85 C1
000007AC: D2 01
000007AD: 74 0F
000007AE: 68 B6
000007AF: 83 11
000007B0: C1 83
000007B1: 01 FA
000007B2: 0F 0D
000007B3: B6 0F
000007B4: 11 84
000007B5: 83 86
000007B6: FA 00
000007B7: 0D 00
000007B8: 74 00
000007B9: 55 85
000007BA: 85 D2
000007BB: D2 0F
000007BC: 74 84
000007BD: 59 86
000007BE: 83 00
000007BF: C1 00
000007C0: 01 00
000007C1: 0F 83
000007C2: B6 C1
000007C3: 11 01
000007C4: 83 0F
000007C5: FA B6
000007C6: 0D 11
000007C7: 74 83
000007C8: 46 FA
000007C9: 85 0D
000007CA: D2 74
000007CB: 74 73
000007CC: 4A 85
000007CD: 83 D2
000007CE: C1 74
000007CF: 01 77
000007D0: 0F 83
000007D1: B6 C1
000007D2: 11 01
000007D3: 83 0F
000007D4: FA B6
000007D5: 0D 11
000007D6: 74 83
000007D7: 37 FA
000007D8: 85 0D
000007D9: D2 74
000007DA: 74 64
000007DB: 3B 85
000007DC: 83 D2
000007DD: C1 74
000007DE: 01 68
000007DF: 0F 83
000007E0: B6 C1
000007E1: 11 01
000007E2: 83 0F
000007E3: FA B6
000007E4: 0D 11
000007E5: 74 83
000007E6: 28 FA
000007E7: 85 0D
000007E8: D2 74
000007E9: 74 55
000007EA: 2C 85
000007EB: 83 D2
000007EC: C1 74
000007ED: 01 59
000007EE: 0F 83
000007EF: B6 C1
000007F0: 11 01
000007F1: 83 0F
000007F2: FA B6
000007F3: 0D 11
000007F4: 74 83
000007F5: 19 FA
000007F6: 85 0D
000007F7: D2 74
000007F8: 74 46
000007F9: 1D 85
000007FA: 83 D2
000007FB: C1 74
000007FC: 01 4A
000007FD: 0F 83
000007FE: B6 C1
000007FF: 11 01
00000800: 83 0F
00000801: FA B6
00000802: 0D 11
00000803: 74 83
00000804: 0A FA
00000805: 85 0D
00000806: D2 74
00000807: 0F 37
00000809: CC D2
0000080A: FE 74
0000080B: FF 3B
0000080C: FF 83
0000080D: EB C1
0000080E: 08 01
0000080F: 83 0F
00000810: C0 B6
00000811: 01 11
00000812: E9 83
00000813: C2 FA
00000814: FE 0D
00000815: FF 74
00000816: FF 28
00000817: C2 85
00000818: 04 D2
00000819: 00 74
0000081A: CC 2C
0000081B: CC 83
0000081C: CC C1
0000081D: CC 01
0000081E: CC 0F
0000081F: CC B6
00000820: 8B 11
00000821: 4C 83
00000822: 24 FA
00000823: 04 0D
00000824: 33 74
00000825: C0 19
00000826: 83 85
00000827: E9 D2
00000828: 01 74
00000829: 83 1D
0000082A: C1 83
0000082B: 01 C1
0000082C: 0F 01
0000082D: B6 0F
0000082E: 11 B6
0000082F: 83 11
00000830: FA 83
00000831: 0D FA
00000832: 74 0D
00000833: 06 74
00000834: 85 0A
00000835: D2 85
00000836: 75 D2
00000837: F1 0F
00000838: EB 85
00000839: 05 CC
0000083A: 83 FE
0000083B: C0 FF
0000083C: 01 FF
0000083E: EA 08
0000083F: C2 83
00000840: 04 C0
00000841: 00 01
00000842: 00 E9
00000843: 00 C2
00000844: 00 FE
00000845: 00 FF
00000846: 00 FF
00000847: 00 C2
00000848: 00 04

[Gunther]

Hi Hutch,

cz.exe from post #1 doesn't work under Win 7-64.

Gunther

[jj2007]

cz.exe on i5, Win7-64:

Code Select Expand

842 ms 1
826 ms 2
873 ms 1
827 ms 2
889 ms 1
827 ms 2
905 ms 1
842 ms 2

[Siekmanski]

Here it's just the other way around, Windows 8.1

Code Select Expand

    cr_cnt2 PROTO :DWORD
    cr_cnt PROTO :DWORD

1140 ms 1
844 ms 2
1141 ms 1
844 ms 2
1157 ms 1
844 ms 2
1140 ms 1
844 ms 2

    cr_cnt PROTO :DWORD
    cr_cnt2 PROTO :DWORD

891 ms 1
828 ms 2
906 ms 1
859 ms 2
890 ms 1
860 ms 2
906 ms 1
859 ms 2


Maybe L1 cache alignment ?

[anunitu]

You of course have to allow for the NSA's read time,and you know they code slow anyway.... :icon_rolleyes: :shock: