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Date:      Sun, 15 Feb 2004 21:46:49 +0100
From:      des@des.no (Dag-Erling =?iso-8859-1?q?Sm=F8rgrav?=)
To:        Alexandr Kovalenko <never@nevermind.kiev.ua>
Cc:        freebsd-hackers@freebsd.org
Subject:    Re: FreeBSD 5.2 v/s FreeBSD 4.9 MFLOPS performance (gcc3.3.3 v/s gcc2.9.5)
Message-ID:  <xzpvfm8yssm.fsf@dwp.des.no>
In-Reply-To: <20040214082420.GB77411@nevermind.kiev.ua> (Alexandr Kovalenko's message of "Sat, 14 Feb 2004 10:24:21 %2B0200")
References:  <BAY12-F37zmBUw7MurD00010899@hotmail.com> <200402101129.34337.wes@softweyr.com> <20040214082420.GB77411@nevermind.kiev.ua>

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Alexandr Kovalenko <never@nevermind.kiev.ua> writes:
> Could you please explain me this? Result is fully reproduceable. Please n=
ote,
> that the only difference is the output file name. Even resulting files ma=
tch
> bit-to-bit. [...]

Definitely some kind of alignment problem, but it only shows up at
some optimization levels and not others.

des@dwp ~/src/flops% ll f*s
lrwxr-xr-x  1 des  des      5 Feb 15 21:34 fffffffffffffffffflops@ -> flops
lrwxr-xr-x  1 des  des      5 Feb 15 21:06 ffffffffffffffffflops@ -> flops
lrwxr-xr-x  1 des  des      5 Feb 15 21:06 fffffffffffffffflops@ -> flops
lrwxr-xr-x  1 des  des      5 Feb 15 21:08 ffffffffffffffflops@ -> flops
lrwxr-xr-x  1 des  des      5 Feb 15 21:08 fffffffffffffflops@ -> flops
lrwxr-xr-x  1 des  des      5 Feb 15 21:08 ffffffffffffflops@ -> flops
lrwxr-xr-x  1 des  des      5 Feb 15 21:03 fffffffffffflops@ -> flops
lrwxr-xr-x  1 des  des      5 Feb 15 21:03 ffffffffffflops@ -> flops
lrwxr-xr-x  1 des  des      5 Feb 15 21:02 fffffffffflops@ -> flops
lrwxr-xr-x  1 des  des      5 Feb 15 21:02 ffffffffflops@ -> flops
lrwxr-xr-x  1 des  des      5 Feb 15 21:02 fffffffflops@ -> flops
lrwxr-xr-x  1 des  des      5 Feb 15 21:02 ffffffflops@ -> flops
lrwxr-xr-x  1 des  des      5 Feb 15 21:02 fffffflops@ -> flops
lrwxr-xr-x  1 des  des      5 Feb 15 21:02 ffffflops@ -> flops
lrwxr-xr-x  1 des  des      5 Feb 15 21:02 fffflops@ -> flops
lrwxr-xr-x  1 des  des      5 Feb 15 21:02 ffflops@ -> flops
lrwxr-xr-x  1 des  des      5 Feb 15 21:02 fflops@ -> flops
-rwxr-xr-x  1 des  des  20875 Feb 15 21:05 flops*
lrwxr-xr-x  1 des  des      5 Feb 15 20:55 flucking-slow-flops@ -> flops
des@dwp ~/src/flops% cc -DUNIX -o flops flops.c
des@dwp ~/src/flops% for f in f*s ; do ./$f |& grep MFLOPS.1. ; done
   MFLOPS(1)       =3D   386.3844
   MFLOPS(1)       =3D   365.9330
   MFLOPS(1)       =3D   364.1425
   MFLOPS(1)       =3D   366.6225
   MFLOPS(1)       =3D   389.3461
   MFLOPS(1)       =3D   377.1758
   MFLOPS(1)       =3D   354.1909
   MFLOPS(1)       =3D   356.5961
   MFLOPS(1)       =3D   371.7964
   MFLOPS(1)       =3D   366.3965
   MFLOPS(1)       =3D   407.1590
   MFLOPS(1)       =3D   375.0376
   MFLOPS(1)       =3D   353.9504
   MFLOPS(1)       =3D   394.1439
   MFLOPS(1)       =3D   134.2436
   MFLOPS(1)       =3D   148.3984
   MFLOPS(1)       =3D   390.5495
   MFLOPS(1)       =3D   373.4338
   MFLOPS(1)       =3D   341.5228
des@dwp ~/src/flops% cc -DUNIX -O0 -o flops flops.c
des@dwp ~/src/flops% for f in f*s ; do ./$f |& grep MFLOPS.1. ; done
   MFLOPS(1)       =3D   392.9511
   MFLOPS(1)       =3D   361.4795
   MFLOPS(1)       =3D   407.0004
   MFLOPS(1)       =3D   368.2120
   MFLOPS(1)       =3D   355.9699
   MFLOPS(1)       =3D   378.2740
   MFLOPS(1)       =3D   372.4568
   MFLOPS(1)       =3D   339.8898
   MFLOPS(1)       =3D   367.3776
   MFLOPS(1)       =3D   379.0460
   MFLOPS(1)       =3D   363.5696
   MFLOPS(1)       =3D   379.5704
   MFLOPS(1)       =3D   390.2681
   MFLOPS(1)       =3D   382.3747
   MFLOPS(1)       =3D   175.9839
   MFLOPS(1)       =3D   131.9588
   MFLOPS(1)       =3D   379.4554
   MFLOPS(1)       =3D   385.6065
   MFLOPS(1)       =3D   363.8399
des@dwp ~/src/flops% cc -DUNIX -O -o flops flops.c
des@dwp ~/src/flops% for f in f*s ; do ./$f |& grep MFLOPS.1. ; done
   MFLOPS(1)       =3D   438.2079
   MFLOPS(1)       =3D   445.7388
   MFLOPS(1)       =3D   143.9707
   MFLOPS(1)       =3D   152.9320
   MFLOPS(1)       =3D   420.0060
   MFLOPS(1)       =3D   450.3305
   MFLOPS(1)       =3D   176.8822
   MFLOPS(1)       =3D   177.4155
   MFLOPS(1)       =3D   453.1921
   MFLOPS(1)       =3D   463.7040
   MFLOPS(1)       =3D   431.8273
   MFLOPS(1)       =3D   440.2074
   MFLOPS(1)       =3D   457.4747
   MFLOPS(1)       =3D   430.3638
   MFLOPS(1)       =3D   438.6455
   MFLOPS(1)       =3D   436.4352
   MFLOPS(1)       =3D   403.4691
   MFLOPS(1)       =3D   429.3843
   MFLOPS(1)       =3D   166.5295
des@dwp ~/src/flops% cc -DUNIX -O2 -o flops flops.c
des@dwp ~/src/flops% for f in f*s ; do ./$f |& grep MFLOPS.1. ; done
   MFLOPS(1)       =3D   486.4274
   MFLOPS(1)       =3D   462.6540
   MFLOPS(1)       =3D   448.6820
   MFLOPS(1)       =3D   483.4713
   MFLOPS(1)       =3D   456.5398
   MFLOPS(1)       =3D   456.2924
   MFLOPS(1)       =3D   458.9312
   MFLOPS(1)       =3D   443.5167
   MFLOPS(1)       =3D   527.0580
   MFLOPS(1)       =3D   488.1867
   MFLOPS(1)       =3D   478.7150
   MFLOPS(1)       =3D   456.2584
   MFLOPS(1)       =3D   476.7231
   MFLOPS(1)       =3D   473.5441
   MFLOPS(1)       =3D   480.3434
   MFLOPS(1)       =3D   457.3464
   MFLOPS(1)       =3D   478.5790
   MFLOPS(1)       =3D   473.1698
   MFLOPS(1)       =3D   444.4634
des@dwp ~/src/flops% cc -DUNIX -O3 -o flops flops.c
des@dwp ~/src/flops% for f in f*s ; do ./$f |& grep MFLOPS.1. ; done
   MFLOPS(1)       =3D   485.9121
   MFLOPS(1)       =3D   470.1213
   MFLOPS(1)       =3D   434.6227
   MFLOPS(1)       =3D   438.2213
   MFLOPS(1)       =3D   460.9863
   MFLOPS(1)       =3D   458.5821
   MFLOPS(1)       =3D   472.2775
   MFLOPS(1)       =3D   438.6205
   MFLOPS(1)       =3D   437.6345
   MFLOPS(1)       =3D   468.6643
   MFLOPS(1)       =3D   432.0184
   MFLOPS(1)       =3D   437.1364
   MFLOPS(1)       =3D   469.7258
   MFLOPS(1)       =3D   463.0537
   MFLOPS(1)       =3D   465.8361
   MFLOPS(1)       =3D   500.6559
   MFLOPS(1)       =3D   458.3052
   MFLOPS(1)       =3D   470.0315
   MFLOPS(1)       =3D   441.1284

DES
--=20
Dag-Erling Sm=F8rgrav - des@des.no



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