NPTL in RH9 vs RHEL3
lharkrider at iologics.com
Wed Apr 14 23:38:37 UTC 2004
I run SAPDB on Redhat9, and am trying to migrate to RHEL3. It is well known
that SAPDB requires the LD_ASSUME_KERNEL=2.2.5 to run on Redhat. Using this
settings, I have run SAPDB on Redhat9 with great success. The same tactic
on RHEL3 results in a much slower, and less stable database.
It seems that on Redhat9, the LD_ASSUME_KERNEL=2.2.5 disables floating
stacks, but somehow leaves NPTL operational (as opposed to toggling
linuxthreads). The getconf command indicates this overtly:
[RH9]# getconf GNU_LIBPTHREAD_VERSION
On RHEL3, however, setting LD_ASSUME_KERNEL=2.2.5 results in nptl being
disabled in favor of linuxthreads:
[RHEL3]# getconf GNU_LIBPTHREAD_VERSION
I also see significant differences when running top on the machines. On the
RH9 box, the number of SAPDB processes remains minimal. One the RHEL3 box,
I see dozens of SAPDB processes. Java behaves similarly.
My questions are:
1) whether or not there is something special about the RH9 glibc or kernels
that allow nptl to function despite the LD_ASSUME_KERNEL=2.2.5 setting?
2) Is it possible to recompile glibc2.3.2-95.6 for RHEL3 such that it
behaves in the same way?
3) Is there a more subtle way to achieve this? Can I discretely disable
floating stacks without using the LD_ASSUME_KERNEL setting? Or could I use
a version of glibc that has no support for linuxthreads at all, or at least
is more reluctant to resort to linux threads?
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