Ibm director of licensing, ibm corporation, north castle drive, armonk, ny 105041785 u. Feedback loop definition of feedback loop by medical. Feedbackdirected data cache optimizations for the x86 ronald d. Feedbacks definition of feedbacks by the free dictionary. Pkstandard stable, and minimizes the closed loop system from w to z. This method has shown good application performance gains, but is not commonly used in practice due to the high runtime overhead of profile collection, the tedious dualcompile usage model, and difficulties in generating representative training data sets.
The section of a control system that allows for feedback and selfcorrection and that adjusts its operation according to differences between the actual. Phoenix feedbackdirected static compiler optimization. In computer science, program optimization or software optimization is the process of modifying a software system to make some aspect of it work more efficiently or use fewer resources. I have contributed to a number of technical topics in programming language design and implementation including the analysis and optimization of objectoriented languages, virtual machine design and implementation, scalable runtime systems, justintime compilation, online feedback directed optimization, and garbage collection. Feedback loop definition of feedback loop by medical dictionary. Overcoming the challenges to feedback directed optimization michael d. Because all analysis and optimization steps are happening during the execution of the application, the time necessary for the analysis adds to the total run time. Performance optimization and tuning techniques for ibm. Feedbackdirected data cache optimizations for the x86. Profile information is collected for the plurality of source code modules by executing the first executable program module. Traditional feedbackdirected optimization fdo in gcc uses static instrumentation to collect edge and value profiles. Does training input selection matter for feedbackdirected optimizations. Feedbackdirected and dynamic optimization how is feedbackdirected and dynamic optimization abbreviated. Performance optimization and tuning techniques for ibm power systems processors including ibm power8 ibm power power systems.
Citeseerx feedbackdirected barrier optimization in a. In one aspect, a first executable program module is generated based on a plurality of source code modules. Feedbackdirected and dynamic optimization how is feedback. Profile data is stale by design, and we have implemented compiler features to deliver stable speedup across releases. Improving memory performance through runtime optimization by joshua jacobs submitted to the department of electrical engineering and computer science on may 24, 2002, in partial fulfillment of the requirements for the degree of masters of engineering in computer science abstract. Feedback directed barrier optimization in a strongly isolated stm. In light of this, this paper presents a feedback directed optimization of tcmalloc. Feedbackdirected optimization is a twostep process where code is instrumented on the first pass of compilation and run using a representative input data set to produce a file containing profiling information. Feedbackdirected optimization is a wellknown method for static compiler optimization. The purpose of this feature is to automatically improve plans for queries that are executed repeatedly, for which the optimizer does not. A case study thomas kistler and michael franz university of california, irvine much of the software in everyday operation is not making optimal use of the hardware on which it.
This paper describes the implementation of an online feedbackdirected. Feedbackdirected barrier optimization in a strongly isolated stm. Feedbackfree networkassisted diversity multiple access. Overall, this research establishes a link between design tools and performance outcomes, while. They plug directly into analytica optimizer with full integration of all features, including uncertainty, dynamic simulation, and intelligent arrays. Before, compiler generates code based on information available only at compile time, and the code generated is often poorly optimized since the information given to compiler is very limited. Performance optimization and tuning techniques for ibm power. Cardinality feedback was introduced in oracle database 11g release 2 and was renamed statistics feedback in oracle database 12c. In light of this, this paper presents a feedbackdirected optimization of tcmalloc. Feedback directed data cache optimizations for the x86 ronald d. Posted on april 29, 2015 may 2, 2015 by raghavendra.
Feedback directed optimization in compaqs compilation tools for. However, online feedback directed optimization is more di cult thano ine feedback directed optimization for two main reasons, increased runtime overhead and the accuracy and availability of the pro le information. Feedback directed arrier optimization 10 checking barriers for the notaccessedintxn pattern. Methods, systems, and apparatus, including computer program products, for interprocedural optimization, are disclosed.
Overcoming the challenges to feedbackdirected optimization michael d. In general, a computer program may be optimized so that it executes more rapidly, or to make it capable of operating with less memory storage or other resources. Feedback directed and dynamic optimization listed as fddo. We also never use affiliate linksprograms if theyre available. Overcoming the challenges to feedbackdirected optimization. Getapp lets you compare the list of tools and vendors that provide feedback and. Online feedbackdirected optimization of java matthew arnoldyz michael hindz barbara g. Hardware feedbackdirected optimization is a much faster method and the optimization is performed on the actual target system as opposed to simulated in the iss. The system works by sampling hardware performance monitors on production machines and using those profiles to guide optimization. Optimization in a strongly isolated stm nathan bronson christos kozyrakis kunle olukotun. There is documentation for this in gcc manual, to quote. Feedbackdirected barrier optimization in a strongly isolated stm nathan g.
This paper describes and evaluates the feedback directed optimizations that are used in the compaq c compiler tool chain for alpha. Feedback directed optimization with gcc and perf spooky. It solves multiunit and plantwide optimization on a minutebyminute basis, even when the plant is not at a steady state. Feedbackdirected and dynamic optimization listed as fddo. In fact, if you are already using one of these solvers with their standard algebraic, try with analytica for a more visual and flexible way to. Does training input selection matter for feedbackdirected. Feedbackdirected thread scheduling with memory considerations.
Feedbackdirected optimization fdo is a general term used to describe any technique that alters a program execution based on tendencies observed in its present or past runs. Us8789032b1 feedbackdirected interprocedural optimization. Autofdo is a system to simplify realworld deployment of feedback directed optimization fdo. Automatic feedbackdirected object inlining in the java. The profit optimizer software integrates with honeywells profit controller applications to deliver costeffective and userfriendly solutions to realtime optimization rto problems. Scribe belongs to the category of content optimization platforms, tightly connected with search and some social. Program counters need to first be mapped to source, which serves as a bridge between the binarylevel profile and compiler ir. Improving memory performance through runtime optimization. Published studies that use feedback directed optimization fdo techniques use either a single input for both training and performance evaluation, or a single input for training and a single input. Feedback directed optimization of tcmalloc semantic scholar. In its general structure, cms resembles other binary translation systems described in the literature, but it is. The use of optimization software requires that the function f is defined in a suitable programming language and connected at compile or run time to the optimization software. Two measures also called norms of how large a stable lti system is are most popular in feedback optimization. The system works by sampling hardware performance monitors on production machines and using those pro.
Gcc uses heuristics to guess branch probabilities if they are not provided by profiling feedback fprofilearcs. The compiler is used to access data from a sample run of the program across a representative input set. Feedback loop definition of feedback loop by the free. The proposed optimization method targets the batch sizes, which determine the aggressiveness and timing of thread cache management mechanisms that move free objects between central and threadlocal caches. Feedback directed optimization fdo is a general term used to describe any technique that alters a program execution based on tendencies observed in its present or past runs. Online feedbackdirected optimization of java proceedings of the. Interested in leveraging customer feedback to grow your business. The effect of performance feedback and optimization on the. I have contributed to a number of technical topics in programming language design and implementation including the analysis and optimization of objectoriented languages, virtual machine design and implementation, scalable runtime systems, justintime compilation, online feedbackdirected optimization, and garbage collection. With receptive, software teams can act strategically, know they are working on the right product improvements. Therefore, the analysis must be fast, which precludes. Matthew arnold, stephen fink, david grove, michael hind, and peter f. Autofdo is a system to simplify realworld deployment of feedbackdirected optimization fdo.
Its essential to ask the right customer feedback questions to happy customers. Feedbackdirected barrier optimization in a strongly. The transmeta code morphing software proceedings of the. Over half of cpu cycles used are now spent in some flavor of fdooptimized binaries.
Feedbackdirected optimistic optimizations in virtual. Improved fdo feedback directed optimization new time profiling determines typical order in which functions are executed. This enables faithful and accurate reconstruction of dynamic program control flow. Based upon profiling, memory distance analysis has shown much promise in predicting data locality and memory dependences, and has seen use in locality based optimizations and. The core of the paper then addresses the following topics. Feedback directed barrier optimization in a strongly. The feedbackdirected method can attain dynamic information about memory references, particularly for programs with irregular access patterns. The results indicate which areas of the program are. Rydery yrutgers university, piscataway, nj, 08854 zibm t.
Profileguided optimization pgo, sometimes pronounced as pogo, also known as profile directed feedback pdf, and feedback directed optimization fdo is a compiler optimization technique in computer programming that uses profiling to improve program runtime performance. Feedbackdirected memory disambiguation through store. This profile information is used to drive several traditional optimizations, as well as a novel algorithm for performing feedbackdirected. Overhead several sources of overhead exist in performing feedback directed optimizations online. A survey of adaptive optimization in virtual machines.
In the case of feedbackdirected optimistic optimizations, the vm optimizes based on preconditions that are likely to hold in the future, but that are not guaranteed. Technical report dcstr469, rutgers university, december 2001. Feedbackdirected optimization fdo is a general term used to describe any technique that alters a programs execution based on tendencies observed in its. Transmetas crusoe microprocessor is a full, systemlevel implementation of the x86 architecture, comprising a native vliw microprocessor with a software layer, the code morphing software cms, that combines an interpreter, dynamic binary translator, optimizer, and runtime system. Feedback directed optimization fdo is a general term used to describe any technique that alters a programs execution based on tendencies observed in its present or past runs. If youre into the excel solver thing, im not sure what the free packages are however, if you know a little bit of math, you can do a lot of damage with the following free for academics at least. Feedbackdirected optimizations in gcc with estimated edge. Traditional feedback directed optimization fdo in gcc uses static instrumentation to collect edge and value profiles. Abstract this paper describes the implementation of an online.