On Fri, 15 Jun 2012 11:48:47 -0400, [email protected] wrote: > Mostly answered these myself. Posting > to help future searchers: > > (1) yes > > (2) yes > > In both cases it seems one should always set > HUGETLB_MORECORE=yes in the environment as > I don't see how that can be made the default > when linking executables.
It cannot be made default because it requires a custom function be used by malloc instead of brk(). Part of what the library does when you set MORECORE=yes is to drop this in place. Also, libhugetlbfs shouldn't interact with Transparent Huge Pages (THP) in any negative way. Because THP only work on anonymous memory, anything setup using libhugetlbfs will be ignored because it is all file backed. > > (3) don't know; doesn't seem worth > the trouble to try it as the added > command utilities seem to be either > (a) wrappers that set the env variables > or (b) interact with newer kernel > hugepage features; i.e. there's not > much value-add It may be possible to build the library, but 2.12 depends on kernel features that are not present in the RHEL 5.X kernels. So you are correct in that it isn't really worthwhile. > > > At 01:14 PM 6/13/2012 -0400, [email protected] wrote: >>Hello, >> >>I'm interested in how the different versions >>behave and relate to each other. Have an >>app that is well suited to hugepages >>and has straightforward linking. This app >>already supports creating it's own work >>areas in hugepage shared memory segments. >>Looking to get as much code and malloc >>into hugepages as possible without changing >>anything. >> >>The app links with 'libhugetlbfs' and works >>under CentOS 5.8 with kernel 2.6.18-308.el5. >>A debug trace shows code segments being >>copied to huge page memory successfully >>and 'pmap -x' shows them as "deleted" >>(really hugepages flag, bug in pmap). >> >>So that's great and I'm quite happy. >> >>What I'm wondering is >> >>1) will higher-version 'libhugetlbfs.so' >>libraries work ok such that binaries linked >>on this system with 1.3 will run properly >>on newer distros and kernels such as >>CentOS 6.2 with 2.12? >> >>2) if (1) is true, will newer features >>such as transparently mapping anonymous >>segments in hugepages work automatically >>in this case? Or is a relink on the >>newer system required? >> >>3) is it possible to build a current >>version of 'libhugetlbfs' and utilities >>on the older RHEL 5.8 distribution to >>get the benefit of the utilities that >>have been added subsequent to version >>1.3? Or will it break due to various >>incompatibilities? I have built and >>installed binutils 2.22 in /usr/local >>if that makes any difference. >> >>I'm hoping someone might know the answers >>to these questions already, without >>exerting effort. No problem if the >>answer is "unknown" or "undefined". >> >>Thanks! >> > > > > ------------------------------------------------------------------------------ > Live Security Virtual Conference > Exclusive live event will cover all the ways today's security and > threat landscape has changed and how IT managers can respond. > Discussions > will include endpoint security, mobile security and the latest in > malware > threats. http://www.accelacomm.com/jaw/sfrnl04242012/114/50122263/ > _______________________________________________ > Libhugetlbfs-devel mailing list > [email protected] > https://lists.sourceforge.net/lists/listinfo/libhugetlbfs-devel ------------------------------------------------------------------------------ Live Security Virtual Conference Exclusive live event will cover all the ways today's security and threat landscape has changed and how IT managers can respond. Discussions will include endpoint security, mobile security and the latest in malware threats. http://www.accelacomm.com/jaw/sfrnl04242012/114/50122263/ _______________________________________________ Libhugetlbfs-devel mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/libhugetlbfs-devel
