From mboxrd@z Thu Jan 1 00:00:00 1970 X-Spam-Checker-Version: SpamAssassin 3.4.4 (2020-01-24) on polar.synack.me X-Spam-Level: X-Spam-Status: No, score=-1.9 required=5.0 tests=BAYES_00,FREEMAIL_FROM autolearn=unavailable autolearn_force=no version=3.4.4 X-Received: by 10.36.28.77 with SMTP id c74mr1229433itc.55.1508582517770; Sat, 21 Oct 2017 03:41:57 -0700 (PDT) X-Received: by 10.157.23.167 with SMTP id j36mr273020otj.7.1508582517735; Sat, 21 Oct 2017 03:41:57 -0700 (PDT) Path: eternal-september.org!reader01.eternal-september.org!reader02.eternal-september.org!news.eternal-september.org!feeder.eternal-september.org!news.unit0.net!peer02.am4!peer.am4.highwinds-media.com!peer02.iad!feed-me.highwinds-media.com!news.highwinds-media.com!k70no2964639itk.0!news-out.google.com!p6ni1249itp.0!nntp.google.com!l196no2958844itl.0!postnews.google.com!glegroupsg2000goo.googlegroups.com!not-for-mail Newsgroups: comp.lang.ada Date: Sat, 21 Oct 2017 03:41:57 -0700 (PDT) Complaints-To: groups-abuse@google.com Injection-Info: glegroupsg2000goo.googlegroups.com; posting-host=217.226.43.121; posting-account=5zx--goAAAD06H29EnWQGKTO-gctuXHl NNTP-Posting-Host: 217.226.43.121 User-Agent: G2/1.0 MIME-Version: 1.0 Message-ID: <498648ad-7a60-4847-b272-772383d197d0@googlegroups.com> Subject: Poor performance after upgrate to xubuntu 17.10 From: Charly Injection-Date: Sat, 21 Oct 2017 10:41:57 +0000 Content-Type: text/plain; charset="UTF-8" X-Received-Body-CRC: 960413407 X-Received-Bytes: 2853 Xref: news.eternal-september.org comp.lang.ada:48542 Date: 2017-10-21T03:41:57-07:00 List-Id: Hi, some months ago I started a new thread about performance for the new gnat-gpl-2017 compiler and a got some usefull helps so I will try it again. When I upgrate to new Software/Hardware I use a litte performance test program that solves Rubics Tangle (https://www.jaapsch.net/puzzles/tangle.htm) with an ada program, using a requested nubmer of tasks or no task at all. The source code can be found here: https://github.com/CharlyGH/tangle. Today I upgrated from xubuntu 17.04 to 17.10 an got the folling problem: Let Tn be the runtime for using n tasks, T0 for no tasks. For all previous versions I got the expected result Tn = T0/n for all 1 <= n <= min(number of cores, 100) The limit of 100 occures, because each task uses another tile/orientation to start with and there are 25 tiles and 4 orientations so 100 combinations to start with. But this limit lies in distant future :-). Now after switching to xubuntu 17.10 I got the following strange results: $ for n in 0 1 2 4 8 ; do ./tangle -t $n; echo "----------------"; done using: 0 tasks duration 2569 ms ---------------- using: 1 tasks duration 2571 ms ---------------- using: 2 tasks duration 2229 ms ---------------- using: 4 tasks duration 3101 ms ---------------- using: 8 tasks duration 2545 ms ---------------- $ The time is almost constant with a maximum for n = 4. This strange result including the maximum at 4 is reproducible. The value for n = 0 or 1 is the almost same as for the previous version of xubuntu. When the program is running, n cores are busy at 100 %, as expected. Booting the old Linux Kernel 4.10 had no effect. My Hardware AMD FX(tm)-8350 Eight-Core Processor Sincerly Charly