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* [Bug target/38306]  New: [4.4 Regression] 15% slowdown of computational kernel
@ 2008-11-28 16:02 jv244 at cam dot ac dot uk
  2010-04-30  9:00 ` [Bug target/38306] [4.4/4.5/4.6 Regression] 15% slowdown w.r.t. 4.3 of computational kernel on some architectures jakub at gcc dot gnu dot org
  0 siblings, 1 reply; 15+ messages in thread
From: jv244 at cam dot ac dot uk @ 2008-11-28 16:02 UTC (permalink / raw)
  To: gcc-bugs

The (to be) attached code runs about ~15% (4.4 vs 4.2) slower compiled with:
gfortran -O3 -march=native -funroll-loops  -ffast-math test.f90

4.4:  5.060s
4.3:  4.376s
4.2:  4.316s

most time would be spent in PD2VAL.

FYI, the cpu is:

cpu family      : 15
model           : 65
model name      : Dual-Core AMD Opteron(tm) Processor 8218
stepping        : 2
cpu MHz         : 2612.084
cache size      : 1024 KB
flags           : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov
pat pse36 clflush mmx fxsr sse sse2 ht syscall nx mmxext fxsr_opt lm 3dnowext
3dnow pni cx16 lahf_lm cmp_legacy svm cr8_legacy

(-march -> -march=k8-sse3 -mcx16 -msahf --param l1-cache-size=64 --param
l1-cache-line-size=64 --param l2-cache-size=1024 -mtune=k8)

on Core2 4.4 is actually faster:

4.4: 4.236s
4.3.0: 4.572s

-march=core2 -mcx16 -msahf --param l1-cache-size=32 --param
l1-cache-line-size=64 -mtune=core2


-- 
           Summary: [4.4 Regression] 15% slowdown of computational kernel
           Product: gcc
           Version: 4.4.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: target
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: jv244 at cam dot ac dot uk
  GCC host triplet: x86_64-unknown-linux-gnu


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=38306


^ permalink raw reply	[flat|nested] 15+ messages in thread
end of thread, other threads:[~2012-01-16 12:40 UTC | newest]

Thread overview: 15+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
     [not found] <bug-38306-4@http.gcc.gnu.org/bugzilla/>
2010-10-01 12:05 ` [Bug target/38306] [4.4/4.5/4.6 Regression] 15% slowdown w.r.t. 4.3 of computational kernel on some architectures jakub at gcc dot gnu.org
2011-02-20 15:33 ` steven at gcc dot gnu.org
2011-02-20 16:24 ` Joost.VandeVondele at pci dot uzh.ch
2011-02-20 16:32 ` Joost.VandeVondele at pci dot uzh.ch
2011-02-20 16:50 ` Joost.VandeVondele at pci dot uzh.ch
2011-02-20 18:59 ` steven at gcc dot gnu.org
2011-02-21  8:29 ` bonzini at gnu dot org
2011-02-21 12:56 ` Joost.VandeVondele at pci dot uzh.ch
2011-04-16 11:17 ` [Bug target/38306] [4.4/4.5/4.6/4.7 " jakub at gcc dot gnu.org
2011-09-09 19:11 ` Joost.VandeVondele at pci dot uzh.ch
2011-09-10  9:52 ` manu at gcc dot gnu.org
2011-09-10 13:11 ` ubizjak at gmail dot com
2011-09-13  8:30 ` Joost.VandeVondele at pci dot uzh.ch
2012-01-16 12:41 ` rguenth at gcc dot gnu.org
2008-11-28 16:02 [Bug target/38306] New: [4.4 Regression] 15% slowdown of computational kernel jv244 at cam dot ac dot uk
2010-04-30  9:00 ` [Bug target/38306] [4.4/4.5/4.6 Regression] 15% slowdown w.r.t. 4.3 of computational kernel on some architectures jakub at gcc dot gnu dot org

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