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IDProjectCategoryView StatusDate SubmittedLast Update
0015566ParaView(No Category)public2015-07-06 20:482015-09-11 16:57
ReporterAlan Scott 
Assigned ToUtkarsh Ayachit 
PrioritynormalSeverityminorReproducibilityhave not tried
PlatformOSOS Version
Product Versiongit-master 
Target VersionFixed in Version4.4 
Summary0015566: ncx.c performance work
DescriptionHere is a .diff that modifies ncx.c. Basically, I am trying to move 32 bit words, rather than bytes (as originally done). This is generally for the Exodus reader.

An optimized version of this code changed from 37.7 seconds (4.3.1) to 23.9 seconds (master, these changes applied) to load a dataset (that I may not share), containing 950,000 cells and 1,400,000 points. This files mods were by far the biggest change.

Note that this is in the netcdf directories. Please ask Utkarsh before applying this patch.

Note to self, OUO tire, Linux.

Test by opening any Exodus file.
TagsNo tags attached.
Topic Name
Attached Filesdiff file icon ncx.c.diff [^] (4,179 bytes) 2015-07-06 20:53 [Show Content]
png file icon Unoptimized.png [^] (1,180,314 bytes) 2015-07-06 20:54
png file icon Optimized-1.png [^] (1,144,463 bytes) 2015-07-06 20:54
patch file icon 0001-Performance-tweaks-by-using-word-operations-instead-.patch [^] (7,793 bytes) 2015-07-23 14:55 [Show Content]

related to 0015399closedUtkarsh Ayachit Exodus modeshapes performance work 
related to 0015568closedUtkarsh Ayachit Master performance work from Alan 

Utkarsh Ayachit (administrator)
2015-07-23 14:55


Attached is a counter patch. Mind testing it as before? I just tried to simplify the logic and avoid running into Windows issues with size of long being 32 bit.
Alan Scott (manager)
2015-07-23 16:26

Nope, this shows the optimizer bug. I will give you a screenshot by e-mail. Do not apply this patch.
Alan Scott (manager)
2015-07-28 18:49

Lets defer this code. There is an optimizer bug that is occurring, and I cannot be sure that I can work around it. Further, the code owners (Unidata netCDF Support <>) are going to implement and test this performance fix. Getting rid of the target version, changing status to open.
Utkarsh Ayachit (administrator)
2015-09-11 16:57

The patches to NetCDF have been upstreamed. We'll inherit them once the are accepted in the official release.

 Issue History
Date Modified Username Field Change
2015-07-06 20:48 Alan Scott New Issue
2015-07-06 20:50 Alan Scott Relationship added related to 0015399
2015-07-06 20:53 Alan Scott File Added: ncx.c.diff
2015-07-06 20:54 Alan Scott File Added: Unoptimized.png
2015-07-06 20:54 Alan Scott File Added: Optimized-1.png
2015-07-06 21:51 Alan Scott Description Updated
2015-07-06 22:10 Alan Scott Target Version => 4.4
2015-07-06 22:13 Alan Scott Relationship added related to 0015568
2015-07-08 16:36 Utkarsh Ayachit Status backlog => todo
2015-07-23 14:55 Utkarsh Ayachit Note Added: 0034818
2015-07-23 14:55 Utkarsh Ayachit File Added: 0001-Performance-tweaks-by-using-word-operations-instead-.patch
2015-07-23 16:26 Alan Scott Note Added: 0034819
2015-07-28 18:49 Alan Scott Note Added: 0034849
2015-07-28 18:49 Alan Scott Status todo => backlog
2015-07-28 18:50 Alan Scott Target Version 4.4 =>
2015-09-11 16:57 Utkarsh Ayachit Note Added: 0035211
2015-09-11 16:57 Utkarsh Ayachit Status backlog => closed
2015-09-11 16:57 Utkarsh Ayachit Assigned To => Utkarsh Ayachit
2015-09-11 16:57 Utkarsh Ayachit Resolution open => fixed
2015-09-11 16:57 Utkarsh Ayachit Fixed in Version => 4.4

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