Task #1263
Test Gromacs with X32 ABI
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
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 (erik@kth.se)
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