https://bugzilla.novell.com/show_bug.cgi?id=691057
https://bugzilla.novell.com/show_bug.cgi?id=691057#c0 Summary: Wrong result of SIMD operations on Intel Core/Core 2 while 100% proper on Opteron Classification: Mono Product: Mono: Runtime Version: 2.10.x Platform: x86 OS/Version: All Status: NEW Severity: Major Priority: P5 - None Component: JIT AssignedTo: [email protected] ReportedBy: [email protected] QAContact: [email protected] CC: [email protected] Found By: Community User Blocker: --- Created an attachment (id=427423) --> (http://bugzilla.novell.com/attachment.cgi?id=427423) Original and simdified version of C# n-body benchmark Description of Problem: I wanted to contribute a simdified version of n-body benchmark to http://shootout.alioth.debian.org/u32/performance.php?test=nbody Program was completed and tested on AMD Opteron (with Mono 2.10.1) and worked perfectly. Results was 100% ok and was a lot faster than nonsimdified (original) version. I contributed new version to benchmark (it still waits for evaluation). In the meantime I also checked program on Intel Core. I was surprised when not only it worked much slower, but also gave improper results. On shootout one can see very similar simdified version of n-body written in C, which gives correct results, so it is not just simd related problem. Also, as I said, on AMD Opteron, everything is fine. Both programs are short and clear. Steps to reproduce the problem: 1. Compile attached nbody.cs (original program) and nbody-simd.cs (referencing Mono.Simd). 2. Run both programs. Actual Results: Result of both programs should be identical regardless of the CPU. Expected Results: Proper result on AMD Opteron, improper on Intel Core/Core 2 (none others tested). How often does this happen? Always Additional Information: Compiled EXE file was moved from one platform to another, so this is not related with msc, but rather JIT. Tested on Windows and Linux (Ubuntu, Gentoo) with same results. -- Configure bugmail: https://bugzilla.novell.com/userprefs.cgi?tab=email ------- You are receiving this mail because: ------- You are the QA contact for the bug. _______________________________________________ mono-bugs maillist - [email protected] http://lists.ximian.com/mailman/listinfo/mono-bugs
