+<b>Update:</b> A new version of FleXML (1.7) was released. Most of the work
+was done by William Dowling, who use it in his own work. The good point is
+that it now use a dynamic buffer, and that the memory usage was greatly
+improved. The downside is that William also changed some things internally,
+and it breaks the hack we devised to bypass the parser, as explained in
+\ref faq_flexml_bypassing. Indeed, this is not a classical usage of the
+parser, and Will didn't imagine that we may have used (and even documented)
+such a crude usage of FleXML. So, we now have to repare the bypassing
+functionnality to use the lastest FleXML version and fix the memory usage in
+SimGrid.
+
+\subsubsection faq_trouble_gras_transport GRAS spits networking error messages
+
+Gras, on real platforms, naturally use regular sockets to communicate. They
+are deeply hiden in the gras abstraction, but when things go wrong, you may
+get some weird error messages. Here are some example, with the probable
+reason:
+
+ - <b>Transport endpoint is not connected</b>: several processes try to open
+ a server socket on the same port number of the same machine. This is
+ naturally bad and each process should pick its own port number for this.\n
+ Maybe, you just have some processes remaining from a previous experiment
+ on your machine.\n
+ Killing them may help, but again if you kill -KILL them, you'll have to
+ wait for a while: they didn't close there sockets properly and the system
+ needs a while to notice that this port is free again.
+
+ - <b>Socket closed by remote side</b>: if the remote process is not
+ supposed to close the socket at this point, it may be dead.
+
+ - <b>Connection reset by peer</b>: I found this on internet about this
+ error. I think it's what's happening here, too:\n
+ <i>This basically means that a network error occurred while the client was
+ receiving data from the server. But what is really happening is that the
+ server actually accepts the connection, processes the request, and sends
+ a reply to the client. However, when the server closes the socket, the
+ client believes that the connection has been terminated abnormally
+ because the socket implementation sends a TCP reset segment telling the
+ client to throw away the data and report an error.\n
+ Sometimes, this problem is caused by not properly closing the
+ input/output streams and the socket connection. Make sure you close the
+ input/output streams and socket connection properly. If everything is
+ closed properly, however, and the problem persists, you can work around
+ it by adding a one-second sleep before closing the streams and the
+ socket. This technique, however, is not reliable and may not work on all
+ systems.</i>\n
+ Since GRAS sockets are closed properly (repeat after me: there is no bug
+ in GRAS), it is either that you are closing your sockets on server side
+ before the client get a chance to read them (use gras_os_sleep() to delay
+ the server), or the server died awfully before the client got the data.
+
+\subsubsection faq_trouble_errors_big_fat_warning I'm told that my XML files are too old.
+
+The format of the XML platform description files is sometimes
+improved. For example, we decided to change the units used in SimGrid
+from MBytes, MFlops and seconds to Bytes, Flops and seconds to ease
+people exchanging small messages. We also reworked the route
+descriptions to allow more compact descriptions.
+
+That is why the XML files are versionned using the 'version' attribute
+of the root tag. Currently, it should read:
+\verbatim
+ <platform version="2">
+\endverbatim
+
+If your files are too old, you can use the simgrid_update_xml.pl
+script which can be found in the tools directory of the archive.
+
+\subsection faq_trouble_valgrind Valgrind-related and other debugger issues
+
+If you don't, you really should use valgrind to debug your code, it's
+almost magic.
+
+\subsubsection faq_trouble_vg_longjmp longjmp madness in valgrind
+
+This is when valgrind starts complaining about longjmp things, just like:
+
+\verbatim ==21434== Conditional jump or move depends on uninitialised value(s)
+==21434== at 0x420DBE5: longjmp (longjmp.c:33)
+==21434==
+==21434== Use of uninitialised value of size 4
+==21434== at 0x420DC3A: __longjmp (__longjmp.S:48)
+\endverbatim
+
+This is the sign that you didn't used the exception mecanism well. Most
+probably, you have a <tt>return;</tt> somewhere within a <tt>TRY{}</tt>
+block. This is <b>evil</b>, and you must not do this. Did you read the section
+about \ref XBT_ex??
+
+\subsubsection faq_trouble_vg_libc Valgrind spits tons of errors about backtraces!
+
+It may happen that valgrind, the memory debugger beloved by any decent C
+programmer, spits tons of warnings like the following :
+\verbatim ==8414== Conditional jump or move depends on uninitialised value(s)
+==8414== at 0x400882D: (within /lib/ld-2.3.6.so)
+==8414== by 0x414EDE9: (within /lib/tls/i686/cmov/libc-2.3.6.so)
+==8414== by 0x400B105: (within /lib/ld-2.3.6.so)
+==8414== by 0x414F937: _dl_open (in /lib/tls/i686/cmov/libc-2.3.6.so)
+==8414== by 0x4150F4C: (within /lib/tls/i686/cmov/libc-2.3.6.so)
+==8414== by 0x400B105: (within /lib/ld-2.3.6.so)
+==8414== by 0x415102D: __libc_dlopen_mode (in /lib/tls/i686/cmov/libc-2.3.6.so)
+==8414== by 0x412D6B9: backtrace (in /lib/tls/i686/cmov/libc-2.3.6.so)
+==8414== by 0x8076446: xbt_dictelm_get_ext (dict_elm.c:714)
+==8414== by 0x80764C1: xbt_dictelm_get (dict_elm.c:732)
+==8414== by 0x8079010: xbt_cfg_register (config.c:208)
+==8414== by 0x806821B: MSG_config (msg_config.c:42)
+\endverbatim
+
+This problem is somewhere in the libc when using the backtraces and there is
+very few things we can do ourselves to fix it. Instead, here is how to tell
+valgrind to ignore the error. Add the following to your ~/.valgrind.supp (or
+create this file on need). Make sure to change the obj line according to
+your personnal mileage (change 2.3.6 to the actual version you are using,
+which you can retrieve with a simple "ls /lib/ld*.so").
+
+\verbatim {
+ name: Backtrace madness
+ Memcheck:Cond
+ obj:/lib/ld-2.3.6.so
+ fun:dl_open_worker
+ fun:_dl_open
+ fun:do_dlopen
+ fun:dlerror_run
+ fun:__libc_dlopen_mode
+}\endverbatim
+
+Then, you have to specify valgrind to use this suppression file by passing
+the <tt>--suppressions=$HOME/.valgrind.supp</tt> option on the command line.
+You can also add the following to your ~/.bashrc so that it gets passed
+automatically. Actually, it passes a bit more options to valgrind, and this
+happen to be my personnal settings. Check the valgrind documentation for
+more information.
+
+\verbatim export VALGRIND_OPTS="--leak-check=yes --leak-resolution=high --num-callers=40 --tool=memcheck --suppressions=$HOME/.valgrind.supp" \endverbatim
+
+\subsubsection faq_trouble_backtraces Truncated backtraces
+
+When debugging SimGrid, it's easier to pass the
+--disable-compiler-optimization flag to the configure if valgrind or
+gdb get fooled by the optimization done by the compiler. But you
+should remove these flages when everything works before going in
+production (before launching your 1252135 experiments), or everything
+will run only one half of the true SimGrid potential.
+
+\subsection faq_deadlock There is a deadlock in my code!!!