C# Performance MS verse Mono Problems
.net, c#, mono, performance
Solution
Could be a memory leak. Mono is fighting an uphill battle; Microsoft made a system and developers had to reverse-engineer most of it. If you really can't figure it out, I would try reporting the bug to the mono developers:
Bugs - Mono (http://www.mono-project.com/Bugs)
Make sure that your mono version is up to date first; 2.10 is ancient. As of now, 3.2.6 is the latest. The packaged version from a package maintainer might not be good enough; try building it from the source tarball, and using that to run your program, before reporting bugs.
If you are using wine-mono or something like that on linux, then make sure that wine and wine-mono are up to date as well.
Problem
I'm working on a fairly straight-forward (school) project. It's a job-shop scheduler. It's single-threaded, it has very limited File I/O (it reads a small problem description, then it goes to work trying to build a solution). The CPU should be the bottleneck. There is no user input/GUI. On my machine, in release mode, without the debugger - in 3 minutes of CPU time, my PC can generate/evaluate 20,000 different schedules for a particular problem. On a comparable *nix machine, executed with mono, in 3 minutes of CPU time, the server manages to generate/evaluate 2,000 different schedules. It's 1/10th the speed. I've compared Python performance between my machine and this particular server and the throughput was nearly identical. The only 'system' call that I could see as being different was a call to ``` Process.GetCurrentProcess().TotalProcessorTime.Minutes ``` But removing it hasn't had any impact. I've tried using --aot -O=all It didn't have any noticeable impact. I've also tried to run the mono profiler against it but the results haven't been as helpful as I had hoped. ``` Hits % Method name 57542 37.45 /usr/bin/mono 11432 7.44 __lll_unlock_wake in /lib64/libpthread.so.0 6898 4.49 System.Linq.Enumerable:Any<jobshop2.JobTask> (System.Collections.Generic.IEnumerable`1<jobshop2.JobTask>,System.Func`2<jobshop2.JobTask, bool>) 6857 4.46 System.Collections.Generic.List`1/Enumerator<jobshop2.JobTask>:MoveNext () 3582 2.33 pthread_cond_wait@@GLIBC_2.3.2 in /lib64/libpthread.so.0 2719 1.77 __lll_lock_wait in /lib64/libpthread.so.0 ``` Of those top six lines - I only recognize two of them as being 'my code' that I could improve upon. In the full output I can see quite a few calls in /lib64/libpthread.so.0 that seem to deal with locking, unlocking, waiting, mutexes, and pthreads. I'm confused by this because it is not a multi-threaded application. I'm going through the Performance page on the mono site but nothing is really jumping out at me as being a problem. I have no doubt that my code is ugly and slow, but I really wasn't expecting such a big performance drop. I'm currently trying to get Linux installed on my desktop so that I can run my app in mono on the same hardware to help eliminate that variable - but I thought someone might be able to offer some suggestions/insight. EDIT: It is version 2.10.8 mono ``` Mono JIT compiler version 2.10.8 (tarball Sat Feb 16 11:51:56 UTC 2013) Copyright (C) 2002-2011 Novell, Inc, Xamarin, Inc and Contributors. www.mono-project.com TLS: __thread SIGSEGV: altstack Notifications: epoll Architecture: amd64 Disabled: none Misc: debugger softdebug LLVM: supported, not enabled. GC: Included Boehm (with typed GC and Parallel Mark) ```