P.Y. Chevalier , A. Freyssinet, D. Hagimont, S. Krakowiak, S. Lacourte and X. Rousset de Pina , Experience with Shared Object Support in the Guide System, 4th Symposium on Experiences with Distributed and Multiprocessor Systems (SEDMS), San Diego, September 1993.  Home/Search   Document Details and Download   Summary   Related Articles   Check

....Exceptions. Availability: Implemented for a network of 486 PCs on Mach 3. 0 micro kernel (Guide 2) The French speaking reader might find more information about IMAG on http: www.imag.fr Information about Guide can be retrieved via anonymous ftp from ftp: ftp.imag.fr pub GUIDE References: [64] [78] 98] 133] 134] 182] 2.55 HAL Developer: University of Illinois at Urbana Champaign Description: oo. inheritance. Forwarding of messages. memory model. parallelism. Both synchronous and asynchronous method calls. Asynchronous calls only when there is no return value. Post processing ....

P. Y. Chevalier, A. Freyssinet, D. Hagimont, S. Krakowiak, S. Lacourte, and X. Rousset de Pina. Experience with shared object support in the Guide system. Symp. on Experiences on Distributed Systems and Multiprocessors, 93.

.... Objects, FOG C [94, 165] Phi Phi Delta Delta H H A A Phi Phi Delta Delta H H A A Phi Phi Delta Delta H H A A Phi Phi Delta Delta H H A A hijklm y t i v i t c a y r a d n u o b Yvon Gourhand Gamma gourhant corto.inria.fr Guide [73, 85, 105, 144, 146, 202] Phi Phi Delta Delta H H A A Phi Phi Delta Delta H H A A Phi Phi Delta Delta H H A A Phi Phi Delta Delta H H A A y t i v i t c a y r a d n u o b http: www.imag.fr ftp: ftp.imag.fr pub GUIDE HAL [119, 141] Phi Phi Delta Delta H H A A ....

P. Y. Chevalier, A. Freyssinet, D. Hagimont, S. Krakowiak, S. Lacourte, and X. Rousset de Pina. Experience with shared object support in the Guide system. Symp. on Experiences on Distributed Systems and Multiprocessors, 93.

....shown in the figure will be described in sufficient detail to support the discussions of distribution in Guide 2 in 6.4, and the design of the load distribution facility in chapter 7. A more comprehensive description may be found in publications form Bull IMAG [Krakowiak 92a, Krakowiak 92b, Chevalier 93] and internal working documents from the Guide 2 project [Cayuela 92, Lacourte 93] 6.3.1 The Object Machine The object machine provides management facilities for objects classes and code libraries. It provides primitives that allow compilers to create classes and code libraries, as well as ....

P. Y. Chevalier, A. Freyssinet, D. Hagimont, S. Krakowiak, S. Lacourte, X. Rousset de Pina: "Experience with Shared Object Support in the Guide System". Proceedings of the fourth Symposium on Experiences with Distributed and Multiprocessor Systems (SEDMS), San Diego, California, September 1993.

....object (1.5 s) where sharing, persistence and protection are not managed. In each context, a cache registers all the object bindings that occured. Then an object fault may find the object in the cache (2) or search the object in its location cluster (3) More detailed measurements are given in [ Chevalier93b] The cost of protection is distributed as follows: Protection checks are done on object and method faults (so it does not put any overhead on direct object invocations) Linkage segments associated with classes are larger. This implies that the probability of finding the address of the ....

....probability of finding the address of the called method in the linkage segment of the class is reduced. Invocations that involve objects from different owners cross context boundaries. Some measurements on simple applications showed that most of object invocations are direct (without faults) Chevalier93b] invocations. 4.3 Safety As the system may support applications written with untrusted compilers, it has to assure the safety of the protection mechanisms. The protection mechanisms provided in the Guide system allow a user to corrupt his own objects, simply by writing and executing an ....

P.Y. Chevalier , A. Freyssinet, D. Hagimont, S. Krakowiak, S. Lacourte and X. Rousset de Pina , Experience with Shared Object Support in the Guide System, 4th Symposium on Experiences with Distributed and Multiprocessor Systems (SEDMS), San Diego, September 1993.

....object (1.5 s) where sharing, persistence and protection are not managed. In each context, a cache registers all the object bindings that occured. Then an object fault may find the object in the cache (2) or search the object in its location cluster (3) More detailed measurements are given in [ Chevalier93b]. The cost of protection is distributed as follows: Protection checks are done on object and method faults (so it does not put any overhead on direct object invocations) Linkage segments associated with classes are larger. This implies that the probability of finding the address of the ....

....probability of finding the address of the called method in the linkage segment of the class is reduced. Invocations that involve objects from different owners cross context boundaries. Some measurements on simple applications showed that most of object invocations are direct (without faults) [Chevalier93b] . We plan to also provide statistics about cross context invocations. 4.3 Safety As the system may support applications written with untrusted compilers, it has to assure the safety of the protection mechanisms. The protection mechanisms provided in the Guide system allow a user to corrupt his ....

P.Y. Chevalier , A. Freyssinet, D. Hagimont, S. Krakowiak, S. Lacourte and X. Rousset de Pina , Experience with Shared Object Support in the Guide System, 4th Symposium on Experiences with Distributed and Multiprocessor Systems (SEDMS), San Diego, September 1993.

....applications. Guide provides a single global address space of potentially persistent objects shared by multithreaded, possibly distributed tasks. This version of the system has been implemented on the Mach 3. 0 microkernel as a base, and used for the support of simple co operative applications [2]. One important goal of the design of Guide was a close integration of the different aspects of the system: programming language, execution structures, long term storage of information. This integration has been achieved through the uniform use of an object model. The distinctive features of the ....

P.-Y. Chevalier, A. Freyssinet, D. Hagimont, S. Krakowiak, S. Lacourte and X. Rousset de Pina, Experience with Shared Object Support in the Guide System, Proceedings of the Fourth Symposium on Experience with Distributed and Multiprocessor Systems , San Diego, CA, Sept. 1993, pp. 157-173

....Our research effort has been done in two phases. We started by building a first prototype of an object support system, based on Unix, and tuned to the needs of one specific language [7] The experience gained from the use of this system was used to design a generic object support subsystem [8], 9] developed on the Mach 3.0 micro kernel [10] ....

P.Y. Chevalier, A. Freyssinet, D. Hagimont, S. Krakowiak, S. Lacourte, X. Rousset de Pina, "Experience with shared object-support in the Guide system", Symposium on Experience with Distributed and Multiprocessor Systems - SEDMS IV, Usenix, San Diego, California, September 1993.

....method call on a C object (1.5 s) where sharing, persistence and protection are not managed. We also measured the frequency of direct calls in the supported applications, and we obtained very good results (between 75 and 90 for most of the applications) A more complete evaluation is given in [Chevalier93] . 3.4.2 Lessons learned and related work The segmentation scheme introduced in the second prototype significantly improved method call performance. A comparable approach has been used in the E project [Schuh90] where an object invocation can only be performed using a local variable (managed on ....

P.Y. Chevalier, A. Freyssinet, D. Hagimont , S. Krakowiak, S. Lacourte and X. Rousset de Pina , Experience with Shared Object Support in the Guide System, 4th Symposium on Experiences with Distributed and Multiprocessor Systems (SEDMS), San Diego, September 1993.

....entry is filled (i.e. the reference is bound in O1) at the first method call from O1 to the object pointed by this reference. After binding, further method calls to the object use indirect addressing through the linkage segment of O1, without further interpretation. This scheme is detailed in [8]. At this step, it is important to notice that an object location is only performed when an object reference is not bound. Even if we have observed that already bound references are the common case [8] we feel it is important to efficiently locate objects, and in particular when objects were ....

....through the linkage segment of O1, without further interpretation. This scheme is detailed in [8] At this step, it is important to notice that an object location is only performed when an object reference is not bound. Even if we have observed that already bound references are the common case [8], we feel it is important to efficiently locate objects, and in particular when objects were gathered in a few clusters using the migration mechanism. 3 Object Location and Migration in the Guide System In this section, we describe the location migration scheme we implemented in the Guide system, ....

P.Y. Chevalier, A. Freyssinet, D. Hagimont, S. Krakowiak, S. Lacourte, X. Rousset de Pina, "Experience with Shared Object Support in the Guide System", 4th Symposium on Experiences with Distributed and Multiprocessor Systems (SEDMS), San Diego, September 1993.

....object (1.5 s) where sharing, persistence and protection are not managed. In each context, a cache registers all the object bindings that occured. Then an object fault may find the object in the cache (2) or search the object in its location cluster (3) More detailed measurements are given in [5]. The cost of protection is distributed as follows: ffl Protection checks are done on object and method faults (so it does not put any overhead on direct object invocations) ffl Linkage segments associated with classes are larger. This implies that the probability of finding the address of the ....

....probability of finding the address of the called method in the linkage segment of the class is reduced. ffl Invocations that involve objects from different owners cross context boundaries. Some measurements on simple applications showed that most of object invocations are direct (without faults) [5]. We plan to also provide statistics about cross context invocations. 4.3 Safety As the system may support applications written with untrusted compilers, it has to assure the safety of the protection mechanisms. The protection mechanisms provided in the Guide system allow a user to corrupt his ....

P.Y. Chevalier, A. Freyssinet, D. Hagimont, S. Krakowiak, S. Lacourte, X. Rousset de Pina, "Experience with Shared Object Support in the Guide System", 4th Symposium on Experiences with Distributed and Multiprocessor Systems (SEDMS), San Diego, September 1993.

....swap disk spaces available on each node. In both spaces, objects are named by unique system references. Access to objects within the VOM is protected. The access protection mechanisms and the location scheme are beyond the scope of this paper; they are described in details in [Hagimont 92] and [Chevalier 93] The interface between VOM and PS is defined in terms of load and store operations. This separation between VOM and PS is useful for the following reasons: it enforces the modularity of the system. One of our goals is to be able to easily reuse existing storage servers such as AFS or Pegasus ....

P.-Y. Chevalier, A. Freyssinet, D. Hagimont, S. Krakowiak and X. Rousset de Pina, "Experience with Shared Object Support in the Guide System", Proc of 4th Symposium on Experiences with Distributed and Multiprocessor Systems, San Diego, CA, September 1993. 15

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