public inbox for gcc-prs@sourceware.org help / color / mirror / Atom feed
From: rwhaley@cs.utk.edu To: gcc-gnats@gcc.gnu.org Cc: rwhaley@cs.utk.edu Subject: c/3913: On Athlon's, gcc 3.0 produces code running 1/2 as fast as gcc 2.95 Date: Wed, 01 Aug 2001 17:56:00 -0000 [thread overview] Message-ID: <20010802005022.26072.qmail@sourceware.cygnus.com> (raw) >Number: 3913 >Category: c >Synopsis: On Athlon's, gcc 3.0 produces code running 1/2 as fast as gcc 2.95 >Confidential: no >Severity: serious >Priority: medium >Responsible: unassigned >State: open >Class: pessimizes-code >Submitter-Id: net >Arrival-Date: Wed Aug 01 17:56:00 PDT 2001 >Closed-Date: >Last-Modified: >Originator: rwhaley@cs.utk.edu >Release: gcc version 3.0 >Organization: >Environment: RedHat Linux 7.1 on a 1.2Ghz Athlon. gcc -v gives: hades. /usr/local/gcc-3.0/bin/gcc -v Reading specs from /usr/local/gcc-3.0/lib/gcc-lib/i686-pc-linux-gnu/3.0/specs Configured with: ./configure --prefix=/usr/local/gcc-3.0 Thread model: single gcc version 3.0 >Description: The new memory fetch scheduling algorithm reduces Athlon performance by a factor of 2 over the one used by gcc 2.95.x. It also appears that the x87 register stack utilization algorithm is worse than 2.95.x as well. Problem is too complex to reduce to 1 single preprocessed file. The full problem is detailed (along with code to reproduce, and assembler outputs) here: http://www.cs.utk.edu/~rwhaley/ATLAS/gcc30.html >How-To-Repeat: http://www.cs.utk.edu/~rwhaley/ATLAS/gcc30.html#dup >Fix: Have option to use 2.95 scheduler for scheduling problem. Have option to use 2.95 x87 register stack for register stack usage problem. >Release-Note: >Audit-Trail: >Unformatted:
next reply other threads:[~2001-08-01 17:56 UTC|newest] Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top 2001-08-01 17:56 rwhaley [this message] 2002-04-24 14:41 rth
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=20010802005022.26072.qmail@sourceware.cygnus.com \ --to=rwhaley@cs.utk.edu \ --cc=gcc-gnats@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).