public inbox for gcc-bugs@sourceware.org help / color / mirror / Atom feed
From: "mattreecebentley at gmail dot com" <gcc-bugzilla@gcc.gnu.org> To: gcc-bugs@gcc.gnu.org Subject: [Bug c++/96750] New: 10-12% performance decrease in benchmark going from GCC8 to GCC9/GCC10 Date: Sun, 23 Aug 2020 06:03:23 +0000 [thread overview] Message-ID: <bug-96750-4@http.gcc.gnu.org/bugzilla/> (raw) https://gcc.gnu.org/bugzilla/show_bug.cgi?id=96750 Bug ID: 96750 Summary: 10-12% performance decrease in benchmark going from GCC8 to GCC9/GCC10 Product: gcc Version: unknown Status: UNCONFIRMED Severity: normal Priority: P3 Component: c++ Assignee: unassigned at gcc dot gnu.org Reporter: mattreecebentley at gmail dot com Target Milestone: --- Created attachment 49102 --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=49102&action=edit Compiler output Have recently been working on a new version of the plf::colony container (plflib.org) and found GCC9 was giving ~10% worse performance on average in a given benchmark than GCC8. Further investigation found GCC10 was just as bad. The effect is repeatable across architectures - I've tested on xubuntu, windows running nuwen mingw, and on Core2 and Haswell CPUs, with and without -march=native specified. Compiler flags are: -O2;-march=native;-std=c++17 Code presented is with an absolute minimum use-case - other benchmarks have not shown such strong performance differences - including both simpler and more complex tests. So I cannot reduce further, please do not ask me to do so. The benchmark in question inserts into a container initially then iterates over container elements repeatedly, randomly erasing and/or inserting new elements. Compilers/environments used: Xubuntu 20: GCC8.4, GCC9.3, GCC10.0.1 Windows 7: Nuwen mingw GCC8.2, nuwen mingw GCC9.2 The attached code output is from the Xubuntu environment. Any questions let me know. I will help where I can, but my knowledge of assembly is limited. Information on code components: Nanotimer is a ~nanosecond-precision sub-timeslice cross-platform timer. Colony is a bucket-array-like unordered sequence container. The attached zip contains the build logs and compiler preprocessed outputs for GCC 8.4, 9.3 and 10.0.1 Thanks- Mat
next reply other threads:[~2020-08-23 6:03 UTC|newest] Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top 2020-08-23 6:03 mattreecebentley at gmail dot com [this message] 2020-08-24 8:47 ` [Bug middle-end/96750] " marxin at gcc dot gnu.org 2020-08-24 9:17 ` glisse at gcc dot gnu.org 2020-08-24 9:38 ` marxin at gcc dot gnu.org 2020-08-24 23:21 ` mattreecebentley at gmail dot com 2020-09-27 23:34 ` mattreecebentley at gmail dot com 2020-09-27 23:35 ` mattreecebentley at gmail dot com 2021-12-22 10:41 ` [Bug ipa/96750] [9/10/11/12 Regression] " pinskia at gcc dot gnu.org 2022-01-21 13:27 ` rguenth at gcc dot gnu.org 2022-05-27 9:43 ` [Bug ipa/96750] [10/11/12/13 " rguenth at gcc dot gnu.org 2022-06-28 10:41 ` jakub at gcc dot gnu.org 2022-10-19 9:21 ` rguenth at gcc dot gnu.org 2022-10-19 9:22 ` rguenth at gcc dot gnu.org 2023-07-07 10:37 ` [Bug ipa/96750] [11/12/13/14 " rguenth at gcc dot gnu.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-96750-4@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).