FreeBSD 5.2 v/s FreeBSD 4.9 MFLOPS performance (gcc3.3.3 v/s
gcc2.9.5)
Dag-ErlingSmørgrav
des at des.no
Sun Feb 15 12:47:03 PST 2004
Alexandr Kovalenko <never at nevermind.kiev.ua> writes:
> Could you please explain me this? Result is fully reproduceable. Please note,
> that the only difference is the output file name. Even resulting files match
> bit-to-bit. [...]
Definitely some kind of alignment problem, but it only shows up at
some optimization levels and not others.
des at 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 at dwp ~/src/flops% cc -DUNIX -o flops flops.c
des at dwp ~/src/flops% for f in f*s ; do ./$f |& grep MFLOPS.1. ; done
MFLOPS(1) = 386.3844
MFLOPS(1) = 365.9330
MFLOPS(1) = 364.1425
MFLOPS(1) = 366.6225
MFLOPS(1) = 389.3461
MFLOPS(1) = 377.1758
MFLOPS(1) = 354.1909
MFLOPS(1) = 356.5961
MFLOPS(1) = 371.7964
MFLOPS(1) = 366.3965
MFLOPS(1) = 407.1590
MFLOPS(1) = 375.0376
MFLOPS(1) = 353.9504
MFLOPS(1) = 394.1439
MFLOPS(1) = 134.2436
MFLOPS(1) = 148.3984
MFLOPS(1) = 390.5495
MFLOPS(1) = 373.4338
MFLOPS(1) = 341.5228
des at dwp ~/src/flops% cc -DUNIX -O0 -o flops flops.c
des at dwp ~/src/flops% for f in f*s ; do ./$f |& grep MFLOPS.1. ; done
MFLOPS(1) = 392.9511
MFLOPS(1) = 361.4795
MFLOPS(1) = 407.0004
MFLOPS(1) = 368.2120
MFLOPS(1) = 355.9699
MFLOPS(1) = 378.2740
MFLOPS(1) = 372.4568
MFLOPS(1) = 339.8898
MFLOPS(1) = 367.3776
MFLOPS(1) = 379.0460
MFLOPS(1) = 363.5696
MFLOPS(1) = 379.5704
MFLOPS(1) = 390.2681
MFLOPS(1) = 382.3747
MFLOPS(1) = 175.9839
MFLOPS(1) = 131.9588
MFLOPS(1) = 379.4554
MFLOPS(1) = 385.6065
MFLOPS(1) = 363.8399
des at dwp ~/src/flops% cc -DUNIX -O -o flops flops.c
des at dwp ~/src/flops% for f in f*s ; do ./$f |& grep MFLOPS.1. ; done
MFLOPS(1) = 438.2079
MFLOPS(1) = 445.7388
MFLOPS(1) = 143.9707
MFLOPS(1) = 152.9320
MFLOPS(1) = 420.0060
MFLOPS(1) = 450.3305
MFLOPS(1) = 176.8822
MFLOPS(1) = 177.4155
MFLOPS(1) = 453.1921
MFLOPS(1) = 463.7040
MFLOPS(1) = 431.8273
MFLOPS(1) = 440.2074
MFLOPS(1) = 457.4747
MFLOPS(1) = 430.3638
MFLOPS(1) = 438.6455
MFLOPS(1) = 436.4352
MFLOPS(1) = 403.4691
MFLOPS(1) = 429.3843
MFLOPS(1) = 166.5295
des at dwp ~/src/flops% cc -DUNIX -O2 -o flops flops.c
des at dwp ~/src/flops% for f in f*s ; do ./$f |& grep MFLOPS.1. ; done
MFLOPS(1) = 486.4274
MFLOPS(1) = 462.6540
MFLOPS(1) = 448.6820
MFLOPS(1) = 483.4713
MFLOPS(1) = 456.5398
MFLOPS(1) = 456.2924
MFLOPS(1) = 458.9312
MFLOPS(1) = 443.5167
MFLOPS(1) = 527.0580
MFLOPS(1) = 488.1867
MFLOPS(1) = 478.7150
MFLOPS(1) = 456.2584
MFLOPS(1) = 476.7231
MFLOPS(1) = 473.5441
MFLOPS(1) = 480.3434
MFLOPS(1) = 457.3464
MFLOPS(1) = 478.5790
MFLOPS(1) = 473.1698
MFLOPS(1) = 444.4634
des at dwp ~/src/flops% cc -DUNIX -O3 -o flops flops.c
des at dwp ~/src/flops% for f in f*s ; do ./$f |& grep MFLOPS.1. ; done
MFLOPS(1) = 485.9121
MFLOPS(1) = 470.1213
MFLOPS(1) = 434.6227
MFLOPS(1) = 438.2213
MFLOPS(1) = 460.9863
MFLOPS(1) = 458.5821
MFLOPS(1) = 472.2775
MFLOPS(1) = 438.6205
MFLOPS(1) = 437.6345
MFLOPS(1) = 468.6643
MFLOPS(1) = 432.0184
MFLOPS(1) = 437.1364
MFLOPS(1) = 469.7258
MFLOPS(1) = 463.0537
MFLOPS(1) = 465.8361
MFLOPS(1) = 500.6559
MFLOPS(1) = 458.3052
MFLOPS(1) = 470.0315
MFLOPS(1) = 441.1284
DES
--
Dag-Erling Smørgrav - des at des.no
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