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diff --git a/TAO/docs/releasenotes/orbcore.html b/TAO/docs/releasenotes/orbcore.html deleted file mode 100644 index f371bfe4966..00000000000 --- a/TAO/docs/releasenotes/orbcore.html +++ /dev/null @@ -1,499 +0,0 @@ -<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN"> -<HTML> -<HEAD> - <META HTTP-EQUIV="Content-Type" CONTENT="text/html; charset=iso-8859-1"> - <META NAME="GENERATOR" CONTENT="Mozilla/4.5b2 [en] (WinNT; I) [Netscape]"> - <TITLE>ORB Core Status</TITLE> -<!-- $Id$ --> -</HEAD> -<BODY TEXT="#000000" BGCOLOR="#FFFFFF"> - -<H3> -<A NAME="orb"></A>ORB & ORB Core</H3> -Point of contact: <A HREF="mailto:nanbor@cs.wustl.edu">Nanbor Wang</A> -<P>Last Update: $Date$ -<P><B>Current status:</B> -<UL> -<LI> -Provides dynamically linked wholesale assignment of ORB strategies for -communication, concurrency, demultiplexing, scheduling, and dispatching -using the ACE Service Configurator framework.</LI> - -<LI> -Supports several concurrency models out of the box: Reactive, Thread-per-Connection, -and ORB-per-thread. The ORB-per-thread design is optimized for real-time -I/O subsystems. (See: <A HREF="../configurations.html">Configuration Guide</A>.)</LI> - -<LI> -Supports <TT>resolve_initial_references("<CORBA Service>")</TT> using -ACE support for multicast.</LI> -</UL> -<B>Known issues:</B> -<UL> -<LI> - -Some CORBA objects need to have access to the ORB. We tend to use -<CODE>TAO_ORB_Core_instance()->orb()</CODE> to fetch the right ORB the -object is using. This is most often true when implementing the -shutdown method which allow other process to shutdown a remote -ORB. Althought this may be the "right" thing to do in TAO, it is not -CORBA compliant and hurts the portability of object implementation. A -common way of getting around this problem is to cache the ORB pointer -in the object when it is created and simply use the cached ORB when -needed. However, remember that there could be multiple ORBs in a -process and a POA may be shared by several ORBs. That means, we may -not handling the object with the same ORB it was created. Collocation -optimization further complicated the problem. <P> At the moment, using -<CODE>TAO_ORB_Core_instance()->orb()</CODE> is the only sane way to -get arond the problem. Though there may be a better way. <P> - -<LI> Object references for objects dynamically created within a server -may not have proper host. (See also <A HREF="#hostfix">recent -fix</A>.) When an object is dynamically created and its object -reference returned, it simply has to "guess" at the host information -that is returned in the IIOP Profile. Currently, it guesses using the -host name, which is a reasonable guess in most cases. However, if -there are multiple interfaces on a machine <I>and</I> they have -different host names, it is possible that the desired effect will not -be realized, i.e., the connection to that new object may use a -different interface from the original object. Currently the only way -to change this is to use the <A -HREF="../Options.html#-ORBhost"><B>-ORBhost</B> option</A> to manually -specify that dynamically-created objects bind to a specific interface -so that their IIOP Profile has the desired hostname. A more desirable -fix is being investigated.<P> </UL> - -<B>Recently Completed Work:</B> -<UL> -<LI> -The ORB Core is ready to throw exceptions received from the wire as a native -C++ exception. Similarly, on the server side, native C++ exceptions are -catched and sent over the wire to the client.</LI> - -<LI> -Added new option <TT>-ORBiioplite</TT> when this option is enabled the -ORB removes a few fields of the GIOP messages that are normally not used, -such as the version numbers, the magic 'GIOP' string, the service context, -the Principal object, etc. This option give us a slight performance improvement -but it is important for extremely low-latency systems (such as avionics), -that fortunately have tightly controlled environments so this kind of optimization -is safe to use.</LI> - -<LI> -The buffers for outgoing CDR streams are allocated from TSS memory pools, -reducing locking on the critical path.</LI> - -<LI> -Several optimizations on the critical path have been implemented, carefully -removing excesive locking, memory allocations and data copying. In some -cases special demarshaling and marshaling functions where written for the -request headers.</LI> - -<LI> -Adding a new option into TAO_Resource_Factory to control the internal lock -used by ORB's reacotr. With "<TT>-ORBreactorlock null</TT>" added into -<TT>svc.conf</TT>, you can eliminate the token inside the Select_Reactor -inside the ORB even on multi-threaded platforms. This eliminate some overheads -caused by synchronizing access to the Select_Reactor. Usually, if you have -TSS ORB and are using reactive concurrency startegy, the ORB are not accessed -by multiple threads, then, you can safely turn the lock off. - -<LI> -Strategized the connection management scheme so that we don't always have -to pay the price of a look up in the connection cache. Basically, we "hold" -a service handler for a string of requests.</LI> - -<LI> -There is no need to call ORB::open if the port is 0. It will automagically -be called when the first stub is created. - -<LI> The ORB now handles nested upcalls correctly. See <A -HREF="../leader_follower.html">this </A>for details on the design of -the solution. - -<LI> Making the collocation table configurable. We can either use a -global collocation table to share objects among ORBs, or use the -per-ORB collocation table. - -<LI> -Implement the inheritance mechanism in Default_Server_Connection_Handler -to access the parent's POA. This is necessary when we are using thread-per-connection -concurrency model. - -<LI> It is often desireable for a server to start up and not have to -specify the TCP port number on which the ORB will listen, i.e., let -the OS decide. While this works properly (by providing an argument -<TT>-ORBport 0</TT>), the actual port number used by the server won't -be available after the server starts listening. TAO now tries to bind -the address when <TT>-ORBport 0</TT> is issued so it can get the -actual address to publish the IOR for clients' use. - -<LI> Added optimization for collocated objects. This optimization -enables TAO to bypass communication layers and talks to collocated -objects directly. - -<LI> -Broke the tight coupling between <TT>CORBA_Object</TT> and <TT>IIOP_Object</TT> -so that multiple <TT>CORBA_Object</TT>s can share a single <TT>IIOP_Object</TT>. -This has a big win in <TT>_narrow</TT> operations. - -<LI> -Eliminated substantial memory leaks in servers. - -<LI> -Added documentation for <B><A HREF="../Options.html#-ORBpoa">-ORBpoa</A></B>, -which allows individual tweaking of the POA's locality (global vs. thread-specific) -independent of the locality of other ORB resources. Also, <B><A HREF="../Options.html#-ORBpoalock">-ORBpoalock</A></B> -and <B><A HREF="../Options.html#-ORBpoamgrlock">-ORBpoamgrlock</A></B> -control locking in the POA and POA manager, respectively, according to -application needs. - -<LI> -Began the process of changing the internals of TAO to use the "underbar" -namespace mapping. This should be completed soon. - -<LI> -The ORBs manipulation of object keys and object ids is now consistent. -Canonically, everything is managed as an opaque sequence of octets. Conversion -to/from strings is permitted, with non-printables turning into a trigraph -<B>\hl</B> where <B>h</B> is the high nibble digit in hex, and <B>l</B> -is the low nibble in hex.</LI> - -<LI> -<TT>CORBA_ORB::run()</TT> should be able to be called multiply in the same -execution path now.</LI> - -<LI> -Fixed the <B>LOCATION_FORWARD</B> capabilities to work as described in -the CORBA 2.1 and the POA specification.</LI> - -<LI> -Fixed problem in the IDL Cubit example which caused the server to dump -core when dealing with <TT>_out</TT> sequence types <I>ONLY</I> when compiled -with G++. It seems that G++ decided to interpret the expression <TT>output -== 0</TT> (where <TT>output</TT> is of type <TT>vector_out</TT>) differently -from Sun's C++ compiler.</LI> - -<LI> -Fixed a slight problem in <A HREF="#hostfix">other recent work</A> where -a servant listening on <TT>INADDR_ANY</TT> reported an IOR with address -<TT>0.0.0.0</TT>. It now reports the default hostname instead.</LI> - -<LI> -Working version of TAO on VxWorks with VME transport.</LI> - -<LI> -TAO now reacts gracefully in the face of a non-existent <TT>svc.conf</TT> -file or simply missing entries in the file. It logs a warning message and -uses default values versions of items which it would normally obtain from -the Service Repository.</LI> - -<LI> -<A NAME="hostfix"></A>Fixed problem where object references for objects -dynamically created within a server do not have proper host, at least if -the desired host was specified using <B><A HREF="../Options.html#-ORBhost">-ORBhost</A></B> -on the command line.</LI> - -<LI> -Added support for <B><A HREF="../Options.html#-ORBsndsock">-ORBsndsock</A></B> -and <B><A HREF="../Options.html#-ORBrcvsock">-ORBrcvsock</A></B> ORB options. -See <A HREF="../Options.html">options documentation</A> for details.</LI> - -<LI> -Added support for pre-established connections using the <B><A HREF="../Options.html#-ORBpreconnect">-ORBpreconnect</A></B> -option. This allows connections to be esablished before any CORBA requests -are made. See <A HREF="../Options.html">options documentation</A> for details.</LI> - -<LI> -Eliminated deprecated <B>-OAxxx</B> options parsed by the Object Adapter -<TT>init</TT> method but no longer used by part of the ORB.</LI> - -<LI> -Made argument parsing within the ORB and POA consume the arguments it parses.</LI> - -<LI> -Placed an optimization in IIOP::Profile that should speed up invocations -on the client side rather substantially. This was done by caching an instance -of <TT>ACE_INET_Addr</TT> in the private portion of <TT>Profile</TT> because -the cost of constructing one for every invocation (in <TT>TAO_GIOP_Invocation::start</TT>) -was simply enormous--the construction was something like 100 cycles on -Solaris. This is all because deep down this ends up calling <TT>gethostbyname()</TT>, -which can be very costly. Of course, this is platform-dependent, so the -improvements may not be as great on a different platform.</LI> - -<LI> -Got rid of need to have compile in TSS ORB Core (<TT>-DTAO_HAS_TSS_ORBCORE</TT>). -This is accomplished by having a Resource Factory (<TT>TAO_Resource_Factory</TT>) -singleton which the ORB Core consults in order to get pointers to resources. -The Resource Factory can be configured to return pointers from thread-specific -storage, or process-global storage. By doing this, the ORB Core is shielded -from ever having to know whether or not its resources are global or not.</LI> - -<LI> -Made all command-line like options look like the standard-professed options, -i.e., <B>-ORBxxx</B> or <B>-OAxxxx</B>.</LI> - -<LI> -Moved ORB option parsing into <TT>TAO_ORB_Core::init()</TT> rather than -in <TT>ORB_init()</TT>.</LI> - -<LI> -Define <TT>_FAR</TT> for all cases as an interim fix for LynxOS.</LI> - -<LI> -Fixed TAO so that the default port of 5001 is defined in <TT>orb_core.h</TT> -config header somewhere rather than in <TT>orbobj.cpp</TT>, and use <B>MAXHOSTNAMELEN</B> -ACE -constant for the hostname buffer.</LI> - -<LI> -Eliminated need for <TT>CORBA::Object</TT> to keep a pointer to its orb -sitting around anywhere.</LI> - -<LI> -Tested <TT>CORBA_ORB::shutdown()</TT> as a manner in which a thread of -control can request that <TT>CORBA_ORB::run()</TT> should return and no -longer service requests. It only honors a <I>wait_for_completion</I> argument -of <B>FALSE</B> right now because we haven't fully explored the issues -which surround doing all the completion.</LI> - -<LI> -Created a brief section in <TT><A HREF="../../TAO-INSTALL.html">$TAO_ROOT/TAO-INSTALL.html</A></TT> -that <I>briefly</I> documents installation on Unix platforms. There is -also a brief section which documents issues that apply across ALL platforms, -such as the fact that TAO and its application will likely not work well -if your ACE is linked through Orbix, VisiBroker, or another ORB. <A HREF="../../ChangeLog">ChangeLog</A> -discovery attribution for this should go to <I>Steve Wohlever <wohlever@mitre.org></I>.</LI> - -<LI> -Implemented <TT>CORBA_ORB::shutdown()</TT> as a manner in which a thread -of control can request that <TT>CORBA_ORB::run()</TT> should return and -no longer service requests.</LI> - -<LI> -Validated movement of Strategy Connector into ORB Core.</LI> - -<LI> -Tested and commited <TT>Connector::connect_n</TT> changes to ACE.</LI> - -<LI> -ACE & TAO compiling cleanly using Sun's CC on Solaris and G++ on Linux. -Also, the ACE tests run properly.</LI> - -<LI> -Use <TT>truss</TT> to verify for <A HREF="mailto:PAUL.G.WEHLAGE@cdev.com">Paul -Wehlage</A> that TAO really uses <TT>select</TT> vs. <TT>recv</TT> for -<B>-R</B> vs. <B>-T</B>.</LI> - -<LI> -Renamed <TT>boa.*</TT> to <TT>poa.*</TT>.</LI> - -<LI> -Renamed following files: Orb_Core.* ->orb_core.* & orbobj.* -> corba_orb.*.</LI> - -<LI> -The lock used in <TT>giop.cpp:626</TT> originally appeared in the IIOP-1.4 -code base. Its purpose was to protect access to the <TT>fwd_profile</TT> -data member. The original features are available, but they are currently -not used because none of our concurrency models present a thread-unsafe -condition. The <A HREF="../../ChangeLog">ChangeLog</A> presents more details -on the subject.</LI> - -<LI> -Fixed problems seen by <A HREF="mailto:brian.r.mendel@boeing.com">Brian -Mendel</A> of Boeing where the Cubit server application was crashing in -<TT>TAO_OA_Connection_Handler::handle_message</TT> when it was trying to -call <TT>CORBA::POA::handle_request</TT> through a NULL <TT>root_poa</TT> -pointer. The NULL pointer resulted from the inadvertent use of the Thread-per-Connection -concurrency model, which is currently incompatible with the ORB-per-thread -model. It was not caught because the change is normally done in configuration -files parsed by the Service Configurator, and VxWorks requires special -code in that area which was not tested until Boeing got hold of the code.</LI> - -<LI> -Clean up build under g++. All 'function used before declared inline' warnings -have been eliminated. Also, all other warnings (except for one that is -nearly unavoidable) have been eliminated.</LI> - -<LI> -Removed BOA and ROA names from the ORB.</LI> - -<LI> -Changed <TT>CORBA_ORB::open()</TT> to return an error status (first cut -at this already there--needs to be checked out).</LI> - -<LI> -Added README file to multiCubit test.</LI> -</UL> -<B>Ongoing Work:</B> -<UL> -<LI> -Verify ACE & TAO on Linux using g++, Solaris using CC, and Solaris -using g++.</LI> - -<LI> -Use Purify to eliminate straggling problems.</LI> - -<LI> -Clean up the internals and analyze for performance bottlenecks using Quantify.</LI> - -<LI> -Resolve <TT>// @@</TT> comment blocks. These are questions or comments -placed in the code by a reviewer (typically Doug).</LI> - -<LI> -Make more and better documentation on the internals of TAO.</LI> -</UL> -<B>Current Work:</B> -<UL>Verify that, in the ORB-per-thread concurrency model, it's possible -to have a factory in each thread that creates a client and returns an object -reference to that client within that thread. This is different from the -model that Sumedh originally had where the factory was trying to turn out -a client in a separate thread/ORB combination. -There is no application which attempts this at the moment, so both a -client and a server will need to be manufactured. Using existing Cubit-like -examples (that poor app is so weary) should reduce development time to -a couple of hours. -The real strategy/solution is to make <TT>CORBA::Object</TT> not keep -a pointer to its orb sitting around anywhere. It should only get it when -it needs it. This should not be difficult to change.</UL> - The interface Dynamic -Any (CORBA v.2.2) is being implemented. It will conform to and implement -all areas of the spec except for the following: -<UL> -<LI> -Interface DynFixed not implemented since TAO does not currently support -the IDL fixed data type.</LI> - -<LI> -Long double data type not supported in accessor and mutator functions.</LI> - -<LI> -Wstring (wide character string) data type not supported in accessor and -mutator functions.</LI> - -<LI> -DynUnion attribute set_as_default in treated as read only.</LI> -</UL> -<B>Critical Work:</B> -<UL> -<LI> -Identify/fix the problems in multithreaded client with TSS resources. This -could be done using the leader-follower model (thread-pool.)</LI> - -<LI> -Support new concurrency models, e.g., Thread-per-Request, thread pool, -etc..</LI> -</UL> -<B>Future work:</B> -<UL> -<LI> -Performance optimizations, such as:</LI> - -<OL> -<LI> -Replace all uses of <TT>new</TT> and <TT>delete</TT> with allocators that -can be put into TSS. The main motivation for this is to eliminate lock -contention when multiple threads need to allocate/deallocate memory, however -it might also be possible to substitute an allocator better-tuned to an -application's specific usage.</LI> -</OL> - -<LI> -Robustness improvements:</LI> - -<OL> -<LI> -Improve connection cache so that it won't crash when there are no more -slots or sockets.</LI> - -<LI> -Add an option to the ORB core, e.g., <B>-ORBnameservicetimeout</B>, to -allow specification of an upper bound on the itime-to-wait for a response -from the ORB's multicast "search" for a running name server.</LI> -</OL> - -<LI> -New features:</LI> - -<OL> -<LI> -Implement <TT>ORB::perform_work</TT> and <TT>ORB::work_pending</TT> so -that <TT>ORB::run</TT> <I>could</I> be implemented in terms of them.</LI> - -<LI> -Improve the <TT>Service Configurator</TT> service entry faking on VxWorks.</LI> - -<LI> -Integrate with realtime upcalls (RTUs).</LI> -</OL> - -<LI> -Internal restructuring:</LI> - -<OL> -<LI> -Create some sort of internal "request" object which carries enough context -to suport deferred method invocation such as one might find in the thread-pool -approach or wherever queuing might occur.</LI> -</OL> - -<LI> -Documentation:</LI> - -<OL> -<LI> -Update ORB Patterns paper to reflect the latest TAO has to offer. Specifically</LI> - -<UL> -<LI> -sections on the Abstract Factory and Concurrency strategies need to be -updated, and the entire paper needs to be reviewed for accuracy w.r.t the -current TAO.</LI> - -<LI> -Metrics must be re-computed.</LI> - -<LI> -Tighten existing discussions.</LI> - -<LI> -Add information on new patterns (such as TSS) which have been used since -initial work.</LI> -</UL> - -<LI> -Make the section in <TT><A HREF="../../TAO-Install.html">$TAO_ROOT/TAO-Install.html</A></TT> -that documents installation on Unix platforms more complete.</LI> -</OL> - -<LI> -Miscellany:</LI> - -<OL> -<LI> -Assist in porting higher level services (e.g., <A HREF="ec.html">Event -Channel</A>) to TAO.</LI> - -<LI> -Compile and verify ACE and TAO on Linux using the Kuck and Associates, -Inc. (KAI) compiler tools.</LI> -</OL> - -<LI> -Potential Optimizations:</LI> - -<OL> -<LI> -There is a certain amount of overhead introduced by the use of TSS Singletons. -TSS singletons are very convenient as the variable does not have to be -passed from function to function. Even though sort of access is generally -acceptable, the overhead of this approach maybe too high when used in code -which is executed frequently (e.g., during an upcall). This critical code -may have to be restructured not to use TSS Singletons because of the high -overhead associated with it.</LI> -</OL> -</UL> - -</BODY> -</HTML> |