CFD Online Logo CFD Online URL
www.cfd-online.com
[Sponsors]
Home > Forums > Software User Forums > OpenFOAM > OpenFOAM Running, Solving & CFD

Very slow start up

Register Blogs Members List Search Today's Posts Mark Forums Read

Reply
 
LinkBack Thread Tools Search this Thread Display Modes
Old   March 3, 2021, 07:44
Default Very slow start up
  #1
New Member
 
NA
Join Date: Oct 2015
Posts: 10
Rep Power: 11
luiceur is on a distinguished road
Hello,


When running on large numbers of cores, we have noticed that the start up of the solver takes very long. We haven't seen it before, and the simulations started almost straight away, but now it takes long time waiting:



Code:
Pstream initialized with:
    floatTransfer      : 0
    nProcsSimpleSum    : 0
    commsType          : nonBlocking
    polling iterations : 0
fileModificationChecking : Monitoring run-time modified files using timeStampMaster (fileModificationSkew 10)
allowSystemOperations : Allowing user-supplied system call operations

// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

Is there a reason for this? Can anything be done about this?


Cheers

Last edited by luiceur; March 3, 2021 at 07:46. Reason: formatting
luiceur is offline   Reply With Quote

Old   March 3, 2021, 15:08
Default
  #2
Senior Member
 
Mark Olesen
Join Date: Mar 2009
Location: https://olesenm.github.io/
Posts: 1,714
Rep Power: 40
olesen has a spectacular aura aboutolesen has a spectacular aura about
Filesystem related?
You don't say how many cores nor which version you are using.
olesen is offline   Reply With Quote

Old   March 3, 2021, 17:15
Default
  #3
New Member
 
NA
Join Date: Oct 2015
Posts: 10
Rep Power: 11
luiceur is on a distinguished road
It could be filesystem related... yes but I cannot say for sure. Certainly I have not seen this behaviour before.
We are talking about 8000+ cores with OF v1912
luiceur is offline   Reply With Quote

Reply

Tags
parallel cluster, simplefoam, slow read, slow simulation

Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are On
Refbacks are On


Similar Threads
Thread Thread Starter Forum Replies Last Post
TimeVaryingMappedFixedValue irishdave OpenFOAM Running, Solving & CFD 32 June 16, 2021 07:55
the speed of parallel computation for over 3 million grid is very slow liujmljm SU2 7 June 27, 2014 17:45
Plz Help on how to start coding (Beginner) Nikhil T Main CFD Forum 0 March 13, 2014 14:09
FSI simulation is DEAD SLOW Lance CFX 6 September 12, 2009 10:00
Lets start the public domain CFD-Project! Heinz Wilkening Main CFD Forum 3 March 11, 1999 23:55


All times are GMT -4. The time now is 15:00.