public inbox for gcc-bugs@sourceware.org help / color / mirror / Atom feed
From: "mnoble at space dot mit dot edu" <gcc-bugzilla@gcc.gnu.org> To: gcc-bugs@gcc.gnu.org Subject: [Bug libfortran/34128] New: slow gfortran 4.x (library?) compared to g77 3.4 Date: Fri, 16 Nov 2007 22:23:00 -0000 [thread overview] Message-ID: <bug-34128-15355@http.gcc.gnu.org/bugzilla/> (raw) The following codes (compiled as demo1.f and demo2.f) PROGRAM demo1 PROGRAM demo2 integer i integer i double precision result double precision result do i=1,8000000 do i=1,500000000 result = sin(i*3.14159) result = i*3.14159 enddo enddo print*,'result = ',result print*,'result = ',result END END reveal marked performance disparities between g77 and gfortran on an x86_64 Debian Linux 4.0 machine with 4 AMD Opteron cores: vendor_id : AuthenticAMD cpu family : 15 model : 65 model name : Dual-Core AMD Opteron(tm) Processor 2216 stepping : 2 cpu MHz : 2400.452 Sample timings are given below, comparing the Debian binary package of g77 3.4.6 against both gfortran 4.1.2 (Debian binary package) & gfortran 4.2.1 (locally built from source). Perhaps a gfortran library issue? Regards, Michael S. Noble -------------------------------------------------------------------- % uname -a Linux rabble 2.6.18-5-amd64 #1 SMP Tue Oct 2 20:37:02 UTC 2007 x86_64 GNU/Linux which g77 && g77 -v /usr/bin/g77 Reading specs from /usr/lib/gcc/x86_64-linux-gnu/3.4.6/specs Configured with: ../src/configure -v --enable-languages=c,c++,f77,pascal --prefix=/usr --libexecdir=/usr/lib --with-gxx-include-dir=/usr/include/c++/3.4 --enable-shared --with-system-zlib --enable-nls --without-included-gettext --program-suffix=-3.4 --enable-__cxa_atexit --enable-clocale=gnu --enable-libstdcxx-debug x86_64-linux-gnu Thread model: posix gcc version 3.4.6 (Debian 3.4.6-5) g77 -o demo1-g77 -O2 demo1.f time ./demo1-g77 result = -0.690680921 real 0m0.562s g77 -o demo2-g77 -O2 demo2.f time ./demo2-g77 result = 1.57079501E+09 real 0m0.041s which gfortran && gfortran -v /usr/bin/gfortran Using built-in specs. Target: x86_64-linux-gnu Configured with: ../src/configure -v --enable-languages=c,c++,fortran,objc,obj-c++,treelang --prefix=/usr --enable-shared --with-system-zlib --libexecdir=/usr/lib --without-included-gettext --enable-threads=posix --enable-nls --program-suffix=-4.1 --enable-__cxa_atexit --enable-clocale=gnu --enable-libstdcxx-debug --enable-mpfr --enable-checking=release x86_64-linux-gnu Thread model: posix gcc version 4.1.2 20061115 (prerelease) (Debian 4.1.1-21) gfortran -o demo1-gfortran -O2 demo1.f time ./demo1-gfortran result = -0.690680921077728 real 0m7.681s gfortran -o demo2-gfortran -O2 demo2.f time ./demo2-gfortran result = 1570795008.00000 real 0m2.085s \rm demo?-gfortran PATH=/usr/local/bin:$PATH which gfortran && gfortran -v /usr/local/bin/gfortran Using built-in specs. Target: x86_64-unknown-linux-gnu Configured with: ./configure --prefix=/usr/local --enable-languages=c,c++,fortran Thread model: posix gcc version 4.2.1 gfortran -o demo1-gfortran -O2 demo1.f -L/usr/local/lib -Wl,-R/usr/local/lib time ./demo1-gfortran result = -0.690680921077728 real 0m7.672s gfortran -o demo2-gfortran -O2 demo2.f -L/usr/local/lib -Wl,-R/usr/local/lib time ./demo2-gfortran result = 1570795008.00000 real 0m2.085s -- Summary: slow gfortran 4.x (library?) compared to g77 3.4 Product: gcc Version: 4.1.2 Status: UNCONFIRMED Severity: normal Priority: P3 Component: libfortran AssignedTo: unassigned at gcc dot gnu dot org ReportedBy: mnoble at space dot mit dot edu GCC build triplet: x86_64-unknown-linux-gnu GCC host triplet: x86_64-unknown-linux-gnu GCC target triplet: x86_64-unknown-linux-gnu http://gcc.gnu.org/bugzilla/show_bug.cgi?id=34128
next reply other threads:[~2007-11-16 22:23 UTC|newest] Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top 2007-11-16 22:23 mnoble at space dot mit dot edu [this message] 2007-11-17 0:08 ` [Bug fortran/34128] " fxcoudert at gcc dot gnu dot org 2007-11-17 22:35 ` bdavis at gcc dot gnu dot org 2007-11-17 22:42 ` fxcoudert at gcc dot gnu dot org 2007-11-18 8:37 ` burnus at gcc dot gnu dot org 2007-12-08 19:00 ` jvdelisle at gcc dot gnu dot org 2007-12-08 19:05 ` jvdelisle at gcc dot gnu dot org 2008-03-29 4:49 ` jvdelisle at gcc dot gnu dot org 2008-03-29 5:28 ` jvdelisle at gcc dot gnu dot org 2008-03-29 21:20 ` jvdelisle at gcc dot gnu dot org 2009-03-28 13:21 ` fxcoudert at gcc dot gnu dot org
Reply instructions: You may reply publicly to this message via plain-text email using any one of the following methods: * Save the following mbox file, import it into your mail client, and reply-to-all from there: mbox Avoid top-posting and favor interleaved quoting: https://en.wikipedia.org/wiki/Posting_style#Interleaved_style * Reply using the --to, --cc, and --in-reply-to switches of git-send-email(1): git send-email \ --in-reply-to=bug-34128-15355@http.gcc.gnu.org/bugzilla/ \ --to=gcc-bugzilla@gcc.gnu.org \ --cc=gcc-bugs@gcc.gnu.org \ /path/to/YOUR_REPLY https://kernel.org/pub/software/scm/git/docs/git-send-email.html * If your mail client supports setting the In-Reply-To header via mailto: links, try the mailto: linkBe sure your reply has a Subject: header at the top and a blank line before the message body.
This is a public inbox, see mirroring instructions for how to clone and mirror all data and code used for this inbox; as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).