Is there a version in a pthreads header file that can be checked? You're right that I am currently checking Linux kernel version, not pthread version. Note that this is *only* in cross-compiling environments; in non cross compiling situations, we actually test the behavior to see if threads have different PIDs or not.
Sent from my phone. No type good. On Mar 15, 2011, at 7:41 PM, "Ralph Castain" <r...@open-mpi.org> wrote: > My point was just that we support the current implementation of pthreads - > not any old one. > > Also, to clarify: Jeff actually tests to see what the thread library does. We > only use the Linux kernel version when cross-compiling since we cannot, in > that case, actually test the support. We know that old Linux kernels have the > old implementation, so we exclude them. Anything else is hit-miss when > cross-compiling. > > > On Mar 15, 2011, at 4:46 PM, Paul H. Hargrove wrote: > >> Sorry, I stated my facts backwards. >> CORRECTED facts: >> >> +The old "LinuxThreads" implementation is the one that gave DIFFERENT pids >> to each pthread. >> + "NPTL" is the current implementation of Pthreads for Linux, and the one >> giving a single pid shared by all pthreads. >> >> So, I hope Ralph's statement is similarly reversed, because "LinuxThreads" >> as not been maintained in years. >> >> -Paul >> >> On 3/15/2011 3:40 PM, Ralph Castain wrote: >>> I believe the test is intended strictly for Linux threads. I don't believe >>> we have ever (intentionally) supported any other thread library in such >>> environments. >>> >>> I'll leave it to Jeff to decide if he feels this is an issue. >>> >>> >>> On Mar 15, 2011, at 4:27 PM, Paul H. Hargrove wrote: >>> >>>> I'd like to point out that it is libpthread and the arguments it passes to >>>> clone(), NOT the Linux kernel version, that is the determining factor (at >>>> least if you have a 2.6.x kernel). The "LinuxThreads" implementation of >>>> Pthreads will give the one-pid-to-rule-them all behavior, while the NPTL >>>> implementation gives unquie pids under any 2.6.x kernel and even w/ some >>>> 2.4.x kernels from Red Hat. >>>> >>>> I have encountered systems on which dynamic linking gave NPTL and static >>>> linking gave LinuxThreads. That is a "gottcha" that I am not certain Jeff >>>> and Ralph have taken into account. >>>> >>>> Note that I have no objection to "we don't support this", but fear that >>>> detection of that situation may be flawed. >>>> >>>> -Paul >>>> >>>> On 3/15/2011 2:14 PM, Ralph Castain wrote: >>>>> Hi folks >>>>> >>>>> Jeff and I encountered a problem when cross-compiling OMPI for Linux. >>>>> Turned out that we had an old test in the code that looked for threads to >>>>> have different pids. Since it couldn't be tested when cross-compiling, >>>>> the test simply assumed this was the case for Linux under those >>>>> conditions - which broke the build for current Linux kernels. >>>>> >>>>> Different pids for threads was last seen in the old RH 4 series (kernel >>>>> 2.6.9 or so). Some code (e.g., waitpid) was also provided to support this >>>>> unusual situation - this code was in fact broken when we updated the >>>>> event library. So even if we were in an old kernel, the code base would >>>>> neither compile nor run. >>>>> >>>>> Rather than trying to continue to support these old kernels, we have >>>>> removed all the stale code that was covered by >>>>> OPAL_THREADS_HAVE_DIFFERENT_PIDS. This removed some complexity from a few >>>>> PLM modules and removed the broken code. >>>>> >>>>> Jeff modified the corresponding .m4 test so we now detect an older >>>>> kernel, print out a nice "we don't support this" message (along with >>>>> noting that earlier versions of OMPI do), and then abort the build. >>>>> >>>>> If you know of some reason to restore support for old Linux kernels, and >>>>> someone willing to do the work to "refresh" that support, please let us >>>>> know. >>>>> >>>>> Ralph& Jeff >>>>> >>>>> >>>>> _______________________________________________ >>>>> devel mailing list >>>>> de...@open-mpi.org >>>>> http://www.open-mpi.org/mailman/listinfo.cgi/devel >>>> -- >>>> Paul H. Hargrove phhargr...@lbl.gov >>>> Future Technologies Group >>>> HPC Research Department Tel: +1-510-495-2352 >>>> Lawrence Berkeley National Laboratory Fax: +1-510-486-6900 >>>> >>>> _______________________________________________ >>>> devel mailing list >>>> de...@open-mpi.org >>>> http://www.open-mpi.org/mailman/listinfo.cgi/devel >>> >>> _______________________________________________ >>> devel mailing list >>> de...@open-mpi.org >>> http://www.open-mpi.org/mailman/listinfo.cgi/devel >> >> -- >> Paul H. Hargrove phhargr...@lbl.gov >> Future Technologies Group >> HPC Research Department Tel: +1-510-495-2352 >> Lawrence Berkeley National Laboratory Fax: +1-510-486-6900 >> >> _______________________________________________ >> devel mailing list >> de...@open-mpi.org >> http://www.open-mpi.org/mailman/listinfo.cgi/devel > > > _______________________________________________ > devel mailing list > de...@open-mpi.org > http://www.open-mpi.org/mailman/listinfo.cgi/devel
