Great. I'll be interested in the following...
1. ldd /usr/bin/ntop (or wherever ntop is loaded)
(This shows the dynamic libraries ntop will be using) ... Look for libc:
libntopreport-3.1.50.so => /devel/lib/libntopreport-3.1.50.so
(0x004d9000)
libntop-3.1.50.so => /devel/lib/libntop-3.1.50.so (0x00cb3000)
libmyrrd-3.1.50.so => /devel/lib/libmyrrd-3.1.50.so (0x001e0000)
...
libc.so.6 => /lib/tls/libc.so.6 (0x00328000)
...
2. Run the libc library and see what extensions it's built with:
$ /lib/tls/libc.so.6
GNU C Library stable release version 2.3.3, by Roland McGrath et al.
Copyright (C) 2004 Free Software Foundation, Inc.
This is free software; see the source for copying conditions.
There is NO warranty; not even for MERCHANTABILITY or FITNESS FOR A
PARTICULAR PURPOSE.
Compiled by GNU CC version 3.3.3 20040412 (Red Hat Linux 3.3.3-7).
Compiled on a Linux 2.4.20 system on 2004-10-28.
Available extensions:
GNU libio by Per Bothner
crypt add-on version 2.1 by Michael Glad and others
>>>> NPTL 0.61 by Ulrich Drepper
The C stubs add-on version 2.1.2.
BIND-8.2.3-T5B
NIS(YP)/NIS+ NSS modules 0.19 by Thorsten Kukuk
Glibc-2.0 compatibility add-on by Cristian Gafton
GNU Libidn by Simon Josefsson
Thread-local storage support included.
For bug reporting instructions, please see:
<http://www.gnu.org/software/libc/bugs.html>.
The >>>> line tells us you ARE running NPTL...
3. If you suspect that NPTL is the problem, you can turn it off on (RedHat
based and derived systems) via this:
export LD_ASSUME_KERNEL=2.4.1
<run ntop as usual>
This has the best explaination of the settings:
http://publib.boulder.ibm.com/infocenter/ws51help/index.jsp?topic=/com.ibm.w
ebsphere.base.doc/info/aes/ae/cins_nptl.html:
"Explanation of LD_ASSUME_KERNEL settings:
LD_ASSUME_KERNEL=2.4.20
This override requests the GLIBC/pthreads implementation that conforms to
kernel ABI version 2.4.20 or later. This implementation is the minimum ABI
required for NPTL. This is the default mode for RHEL 3. <snip />
LD_ASSUME_KERNEL=2.4.19
This override requests the GLIBC/pthreads implementation that conforms to
kernel ABI version 2.4.1. This implementation is commonly referred to as
standard LinuxThreads with floating stacks.
This implementation has been the standard implementation of threading on
Linux for several years. <snip />
Tip: The higher performing NPTL implementation has only recently replaced
LinuxThreads with floating stack size as the default threading model in
commercial distributions.
LD_ASSUME_KERNEL=2.2.5
This override requests the GLIBC/pthreads implementation that conforms to
kernel ABI version 2.4.0. This implementation is commonly referred to as
LinuxThreads with fixed stack size.
LinuxThreads with fixed stack size is the original implementation of
threading for Linux. For the past several years, LinuxThreads with floating
stacks has superseded this fixed stack size implementation. The fixed stack
size implementation should be rarely, if ever, needed. Older legacy
applications might require it."
This explains how/why it works:
http://people.redhat.com/drepper/assumekernel.html
-----Burton
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