From:	Alex Vinokur <alexvn AT bigfoot DOT com>
Newsgroups:	comp.os.msdos.djgpp,comp.lang.c++
Subject:	Re: Optimization and operator&&
Date:	Tue, 04 Jun 2002 17:25:45 +0200
Lines:	309
Message-ID:	<3CFCDBF9.CCDA33@bigfoot.com>
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Heinz Ozwirk wrote:

> "Alex Vinokur" <alexvn AT bigfoot DOT com> wrote in message
> news:3CFCB642 DOT 252CFFF7 AT bigfoot DOT com...
> >
> > ###############
> > Windows98
> > gcc/gpp 2.95.3
> > ###############
> >
> >
> > A program below measures performance (time) :
> >   * of operator&& and operator+
> >   * with automatic and static unsigned int
> >   * with optimizations : No optimization, O1, O2, O3
> >
> > We can see that Optimization causes
> >   an increase in elapsed time for operator&& .
> > Any explanation?
> ...
>

[snip]

>
> ...
>
> Your results are useless. They differ by about 25%. Probably the resolution
> of your timer is too large (or your processor is too fast). Run your tests
> again, but this time measure at least 10,000,000 iterations.
>
> Regards
>     Heinz

Here are results with 10,000,000 iterations.

|| ###### Compilation & Run : BEGIN ########
|| No optimization

%gpp main.c -o a0.exe

%a0
--- static uint with OR ---
static, OR [1] Total time : 186986
static, OR [2] Total time : 187100
static, OR [3] Total time : 181918
static, OR [4] Total time : 193440
static, OR [5] Total time : 177352
static, OR [6] Total time : 182445
static, OR [7] Total time : 185969
static, OR [8] Total time : 204047
static, OR [9] Total time : 176972
static, OR [10] Total time : 191458
1

--- automatic uint with OR ---
automatic, OR [1] Total time : 155021
automatic, OR [2] Total time : 162307
automatic, OR [3] Total time : 161321
automatic, OR [4] Total time : 158908
automatic, OR [5] Total time : 155007
automatic, OR [6] Total time : 163801
automatic, OR [7] Total time : 156468
automatic, OR [8] Total time : 179410
automatic, OR [9] Total time : 153427
automatic, OR [10] Total time : 159329
1


--- static uint with PLUS ---
static, PLUS [1] Total time : 130308
static, PLUS [2] Total time : 168823
static, PLUS [3] Total time : 159669
static, PLUS [4] Total time : 167224
static, PLUS [5] Total time : 162690
static, PLUS [6] Total time : 159877
static, PLUS [7] Total time : 166417
static, PLUS [8] Total time : 168937
static, PLUS [9] Total time : 192566
static, PLUS [10] Total time : 143504
520000123

--- automatic uint with PLUS ---
automatic, PLUS [1] Total time : 118877
automatic, PLUS [2] Total time : 172795
automatic, PLUS [3] Total time : 130224
automatic, PLUS [4] Total time : 172183
automatic, PLUS [5] Total time : 179725
automatic, PLUS [6] Total time : 132234
automatic, PLUS [7] Total time : 162603
automatic, PLUS [8] Total time : 168805
automatic, PLUS [9] Total time : 158866
automatic, PLUS [10] Total time : 101873
520000123

|| No optimization
|| ###### Compilation & Run : END ##########




|| ###### Compilation & Run : BEGIN ########
|| Optimization O1

%gpp -O1 main.c -o a1.exe

%a1

--- static uint with OR ---
static, OR [1] Total time : 266250
static, OR [2] Total time : 266729
static, OR [3] Total time : 264779
static, OR [4] Total time : 265749
static, OR [5] Total time : 267403
static, OR [6] Total time : 285114
static, OR [7] Total time : 267340
static, OR [8] Total time : 266558
static, OR [9] Total time : 265249
static, OR [10] Total time : 267702
1

--- automatic uint with OR ---
automatic, OR [1] Total time : 206321
automatic, OR [2] Total time : 203833
automatic, OR [3] Total time : 203991
automatic, OR [4] Total time : 202252
automatic, OR [5] Total time : 208034
automatic, OR [6] Total time : 230505
automatic, OR [7] Total time : 204599
automatic, OR [8] Total time : 204595
automatic, OR [9] Total time : 206029
automatic, OR [10] Total time : 202169
1


--- static uint with PLUS ---
static, PLUS [1] Total time : 108653
static, PLUS [2] Total time : 85620
static, PLUS [3] Total time : 107325
static, PLUS [4] Total time : 82642
static, PLUS [5] Total time : 101233
static, PLUS [6] Total time : 69925
static, PLUS [7] Total time : 74159
static, PLUS [8] Total time : 83076
static, PLUS [9] Total time : 121495
static, PLUS [10] Total time : 91547
520000123

--- automatic uint with PLUS ---
automatic, PLUS [1] Total time : 120268
automatic, PLUS [2] Total time : 108772
automatic, PLUS [3] Total time : 85033
automatic, PLUS [4] Total time : 71257
automatic, PLUS [5] Total time : 113443
automatic, PLUS [6] Total time : 92257
automatic, PLUS [7] Total time : 120099
automatic, PLUS [8] Total time : 110701
automatic, PLUS [9] Total time : 88308
automatic, PLUS [10] Total time : 113803
520000123

|| Optimization O1
|| ###### Compilation & Run : END ##########



|| ###### Compilation & Run : BEGIN ########
|| Optimization O2

%gpp -O2 main.c -o a2.exe

%a2

--- static uint with OR ---
static, OR [1] Total time : 265420
static, OR [2] Total time : 265139
static, OR [3] Total time : 266852
static, OR [4] Total time : 289894
static, OR [5] Total time : 267484
static, OR [6] Total time : 269460
static, OR [7] Total time : 271028
static, OR [8] Total time : 276708
static, OR [9] Total time : 264799
static, OR [10] Total time : 266163
1

--- automatic uint with OR ---
automatic, OR [1] Total time : 216503
automatic, OR [2] Total time : 199450
automatic, OR [3] Total time : 198319
automatic, OR [4] Total time : 202438
automatic, OR [5] Total time : 196483
automatic, OR [6] Total time : 195153
automatic, OR [7] Total time : 229314
automatic, OR [8] Total time : 196878
automatic, OR [9] Total time : 198165
automatic, OR [10] Total time : 200474
1


--- static uint with PLUS ---
static, PLUS [1] Total time : 118224
static, PLUS [2] Total time : 77882
static, PLUS [3] Total time : 90267
static, PLUS [4] Total time : 117555
static, PLUS [5] Total time : 103510
static, PLUS [6] Total time : 73175
static, PLUS [7] Total time : 82098
static, PLUS [8] Total time : 122037
static, PLUS [9] Total time : 89492
static, PLUS [10] Total time : 117505
520000123

--- automatic uint with PLUS ---
automatic, PLUS [1] Total time : 43896
automatic, PLUS [2] Total time : 43496
automatic, PLUS [3] Total time : 44762
automatic, PLUS [4] Total time : 44905
automatic, PLUS [5] Total time : 43497
automatic, PLUS [6] Total time : 44764
automatic, PLUS [7] Total time : 46072
automatic, PLUS [8] Total time : 43496
automatic, PLUS [9] Total time : 44183
automatic, PLUS [10] Total time : 44672
520000123

|| Optimization O2
|| ###### Compilation & Run : END ##########




|| ###### Compilation & Run : BEGIN ########
|| Optimization O3

%gpp -O3 main.c -o a3.exe

%a3

--- static uint with OR ---
static, OR [1] Total time : 264211
static, OR [2] Total time : 296462
static, OR [3] Total time : 267027
static, OR [4] Total time : 265602
static, OR [5] Total time : 266299
static, OR [6] Total time : 265855
static, OR [7] Total time : 267083
static, OR [8] Total time : 285704
static, OR [9] Total time : 266744
static, OR [10] Total time : 272728
1

--- automatic uint with OR ---
automatic, OR [1] Total time : 196533
automatic, OR [2] Total time : 197453
automatic, OR [3] Total time : 199607
automatic, OR [4] Total time : 223342
automatic, OR [5] Total time : 197136
automatic, OR [6] Total time : 194653
automatic, OR [7] Total time : 203098
automatic, OR [8] Total time : 198691
automatic, OR [9] Total time : 193992
automatic, OR [10] Total time : 194465
1


--- static uint with PLUS ---
static, PLUS [1] Total time : 134800
static, PLUS [2] Total time : 74704
static, PLUS [3] Total time : 84592
static, PLUS [4] Total time : 99971
static, PLUS [5] Total time : 72234
static, PLUS [6] Total time : 79407
static, PLUS [7] Total time : 99243
static, PLUS [8] Total time : 150875
static, PLUS [9] Total time : 82086
static, PLUS [10] Total time : 100408
520000123

--- automatic uint with PLUS ---
automatic, PLUS [1] Total time : 43496
automatic, PLUS [2] Total time : 45323
automatic, PLUS [3] Total time : 44284
automatic, PLUS [4] Total time : 43496
automatic, PLUS [5] Total time : 44383
automatic, PLUS [6] Total time : 43882
automatic, PLUS [7] Total time : 43632
automatic, PLUS [8] Total time : 44628
automatic, PLUS [9] Total time : 43907
automatic, PLUS [10] Total time : 43496
520000123

|| Optimization O3
|| ###### Compilation & Run : END ##########



Regards,
  ===========================
  Alex Vinokur
    mailto:alexvn AT bigfoot DOT com
    mailto:alexvn AT go DOT to
    http://up.to/alexvn
    http://go.to/alexv_math
  ===========================

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