Bug 38013 - 90% Speed Slowdown in 4.2.1 vs
Summary: 90% Speed Slowdown in 4.2.1 vs
Status: NEW
Alias: None
Product: Runtime
Classification: Mono
Component: General ()
Version: 4.2.0 (C6)
Hardware: PC Linux
: --- normal
Target Milestone: ---
Assignee: Bugzilla
Depends on:
Reported: 2016-01-25 21:30 UTC by Jared
Modified: 2016-02-16 13:27 UTC (History)
4 users (show)

Is this bug a regression?: ---
Last known good build:

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Description Jared 2016-01-25 21:30:58 UTC
We have an open source project LEAN (github.com/QuantConnect/Lean). We've seen a 90% slow down in our basic benchmarks since upgrading to Mono v4.2.1

e.g. Normal Speed : v4.0.5.1 - 23k/points/sec 
     New Speed    : v4.2.1   - 3k/points/sec

This is very repeatable. We've tested on different hardware, to confirm.

I have no proof of this but believe its from the new Threadpool as our application is intensely dependent on the threads.

To reproduce download the open source project and build using xbuild or visual studio, execute the project and read the speed output. Repeat using latest version of Mono.
Comment 1 Ludovic Henry 2016-02-16 13:27:04 UTC
Hi Jared,

Did you try running with the log profiler, and analyse the output with mprof-report (http://www.mono-project.com/docs/debug+profile/profile/profiler/) ?

If you do, please copy/paste the output for both runs, so we can compare what are the differences.

Thank you very much for your report,