Bug 20541 - Performance Issue Async Read
Summary: Performance Issue Async Read
Alias: None
Product: Class Libraries
Classification: Mono
Component: mscorlib ()
Version: 3.2.x
Hardware: Other Linux
: --- normal
Target Milestone: Untriaged
Assignee: Bugzilla
Depends on:
Reported: 2014-06-11 16:38 UTC by nicholas.rudh
Modified: 2014-07-07 14:59 UTC (History)
2 users (show)

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

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Description nicholas.rudh 2014-06-11 16:38:07 UTC
I am currently running mono 3.2.8 on a Xilinx Zynq board (ARM processor); OS is Petalinux v2013.10 (Yocto 1.4). I have also used mono version 2.11.4 on this board and had run the unit tests in $MONODIR/mono/tests to verify the port was successful. I was comparing the old benchmark times with the current ones, and I noticed “async_read.exe” was significantly worse when run on 3.2.8. 
Mono 2.11.4 ran this unit test in: 24 seconds
Mono 3.2.8 ran the unit test in: 208 seconds
I have run this specific test several times to make sure it wasn’t a fluke, I was wondering if there is an explanation for the slowness. I would be willing to look into the problem if I knew what was changed with regards to this unit test. 
Just to add some more information when I looked into what section of the code was so slow I found it to be the loop using FileStream.BeginRead and FileStream.EndRead. Lines 30 to 32 in async_read.cs
Thank you for your time
Comment 1 Marek Safar 2014-07-04 11:29:19 UTC
This is IO test. I am not sure it's very reliable to compare IO test especially when it contains Thread.Sleep
Comment 2 nicholas.rudh 2014-07-07 14:59:22 UTC
Thank you for the response, could you explain why this is insignificant. I would like to write a white paper for the issue, so that there is documentation for my organization going forward. Sorry if this is a trivial issue.