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Task #1263

Test Gromacs with X32 ABI

Added by Roland Schulz about 4 years ago. Updated about 3 years ago.

Status:
Closed
Priority:
Low
Assignee:
Category:
mdrun
Target version:
Difficulty:
uncategorized
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Description

Given that we never need more than 4GB, X32 ABI (http://en.wikipedia.org/wiki/X32_ABI) shouldn't have any disadvantage and it could give us very slightly better performance. So it might be worth testing it.

Associated revisions

Revision 72e3e8f5 (diff)
Added by Erik Lindahl about 3 years ago

Make source compile under Linux X32 ABI

The X32 ABI uses 32-bit pointers in combination with all
other features of x86-64 to save memory. This requires two
minor changes to x86 inline assembly macro checks, where we
need check for LP64 (64-bit pointers) rather than
x86_64 (which is set for X32). The resulting binaries
run approximately 2% faster, but since it requires all
dependent libraries to be available in X32 format it is
not something we will enable with a simple setting for now.
To use it manually, set CFLAGS and CXXFLAGS to "-O3 -mx32".

Fixes #1263.

Change-Id: I2555b2c68d4bba24f4e581268c472a47fe7d1531

History

#1 Updated by Berk Hess about 4 years ago

  • Status changed from New to Accepted

It seems floating point performance is nearly unaffected and we avoid pointer operations as much as possible in Gromacs, so I expect very little gain. But if it's easy to try, we should. On OpenSuse x32 libraries are not readily available. But for Ubuntu the situation seems to be better:
http://www.phoronix.com/scan.php?page=news_item&px=MTM1OTA

#2 Updated by Mark Abraham about 4 years ago

If there was a benefit, it seems like we'd just need to detect it exists and is supported by the tool chain, and give the right GCC flag, yes?

#3 Updated by Alexey Shvetsov about 4 years ago

Seems like easyest way to test it is to run a minimal x32 system in LXC container (e.g. gentoo or may be debian build)

#4 Updated by Gerrit Code Review Bot about 3 years ago

Gerrit received a related patchset '1' for Issue #1263.
Uploader: Erik Lindahl ()
Change-Id: I2555b2c68d4bba24f4e581268c472a47fe7d1531
Gerrit URL: https://gerrit.gromacs.org/3668

#5 Updated by Erik Lindahl about 3 years ago

  • Status changed from Accepted to Fix uploaded

#6 Updated by Erik Lindahl about 3 years ago

  • Status changed from Fix uploaded to Resolved

#7 Updated by Erik Lindahl about 3 years ago

  • Status changed from Resolved to Closed

#8 Updated by Teemu Murtola about 3 years ago

  • Assignee changed from Berk Hess to Erik Lindahl
  • Target version set to 5.0

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