Runtime-assisted optimizations in the on-chip memory hierarchy

Following Moore's Law, the number of transistors on chip has been increasing exponentially, which has led to the increasing complexity of modern processors. As a result, the efficient programming of such systems has become more difficult. Many programming models have been developed to answer this issue. Of particular interest are task-based programming models that employ simple annotations to define parallel work in an application. The information available at the level of the runtime systems associated with these programming models offers great potential for improving hardware design. Moreover, due to technological limitations, Moore's Law is predicted to eventually come to an end, so novel paradigms are necessary to maintain the current performance improvement trends. The main goal of this thesis is to exploit the knowledge about a parallel application available at the runtime system level to improve the design of the on-chip memory hierarchy. The coupling of the runtime system and the microprocessor enables a better hardware design without hurting the programmability. The first contribution is a set of insertion policies for shared last-level caches that exploit information about tasks and task data dependencies. The intuition behind this proposal revolves around the observation that parallel threads exhibit different memory access patterns. Even within the same thread, accesses to different variables often follow distinct patterns. The proposed policies insert cache lines into different logical positions depending on the dependency type and task type to which the corresponding memory request belongs. The second proposal optimizes the execution of reductions, defined as a programming pattern that combines input data to form the resulting reduction variable. This is achieved with a runtime-assisted technique for performing reductions in the processor's cache hierarchy. The proposal's goal is to be a universally applicable solution regardless of the reduction variable type, size and access pattern. On the software level, the programming model is extended to let a programmer specify the reduction variables for tasks, as well as the desired cache level where a certain reduction will be performed. The source-to-source compiler and the runtime system are extended to translate and forward this information to the underlying hardware. On the hardware level, private and shared caches are equipped with functional units and the accompanying logic to perform reductions at the cache level. This design avoids unnecessary data movements to the core and back as the data is operated at the place where it resides. The third contribution is a runtime-assisted prioritization scheme for memory requests inside the on-chip memory hierarchy. The proposal is based on the notion of a critical path in the context of parallel codes and a known fact that accelerating critical tasks reduces the execution time of the whole application. In the context of this work, task criticality is observed at a level of a task type as it enables simple annotation by the programmer. The acceleration of critical tasks is achieved by the prioritization of corresponding memory requests in the microprocessor.Siguiendo la ley de Moore, el número de transistores en los chips ha crecido exponencialmente, lo que ha comportado una mayor complejidad en los procesadores modernos y, como resultado, de la dificultad de la programación eficiente de estos sistemas. Se han desarrollado muchos modelos de programación para resolver este problema; un ejemplo particular son los modelos de programación basados en tareas, que emplean anotaciones sencillas para definir los Trabajos paralelos de una aplicación. La información de que disponen los sistemas en tiempo de ejecución (runtime systems) asociada con estos modelos de programación ofrece un enorme potencial para la mejora del diseño del hardware. Por otro lado, las limitaciones tecnológicas hacen que la ley de Moore pueda dejar de cumplirse próximamente, por lo que se necesitan paradigmas nuevos para mantener las tendencias actuales de mejora de rendimiento. El objetivo principal de esta tesis es aprovechar el conocimiento de las aplicaciones paral·leles de que dispone el runtime system para mejorar el diseño de la jerarquía de memoria del chip. El acoplamiento del runtime system junto con el microprocesador permite realizar mejores diseños hardware sin afectar Negativamente en la programabilidad de dichos sistemas. La primera contribución de esta tesis consiste en un conjunto de políticas de inserción para las memorias caché compartidas de último nivel que aprovecha la información de las tareas y las dependencias de datos entre estas. La intuición tras esta propuesta se basa en la observación de que los hilos de ejecución paralelos muestran distintos patrones de acceso a memoria e, incluso dentro del mismo hilo, los accesos a diferentes variables a menudo siguen patrones distintos. Las políticas que se proponen insertan líneas de caché en posiciones lógicas diferentes en función de los tipos de dependencia y tarea a los que corresponde la petición de memoria. La segunda propuesta optimiza la ejecución de las reducciones, que se definen como un patrón de programación que combina datos de entrada para conseguir la variable de reducción como resultado. Esto se consigue mediante una técnica asistida por el runtime system para la realización de reducciones en la jerarquía de la caché del procesador, con el objetivo de ser una solución aplicable de forma universal sin depender del tipo de la variable de la reducción, su tamaño o el patrón de acceso. A nivel de software, el modelo de programación se extiende para que el programador especifique las variables de reducción de las tareas, así como el nivel de caché escogido para que se realice una determinada reducción. El compilador fuente a Fuente (compilador source-to-source) y el runtime ssytem se modifican para que traduzcan y pasen esta información al hardware subyacente, evitando así movimientos de datos innecesarios hacia y desde el núcleo del procesador, al realizarse la operación donde se encuentran los datos de la misma. La tercera contribución proporciona un esquema de priorización asistido por el runtime system para peticiones de memoria dentro de la jerarquía de memoria del chip. La propuesta se basa en la noción de camino crítico en el contexto de los códigos paralelos y en el hecho conocido de que acelerar tareas críticas reduce el tiempo de ejecución de la aplicación completa. En el contexto de este trabajo, la criticidad de las tareas se considera a nivel del tipo de tarea ya que permite que el programador las indique mediante anotaciones sencillas. La aceleración de las tareas críticas se consigue priorizando las correspondientes peticiones de memoria en el microprocesador.Seguint la llei de Moore, el nombre de transistors que contenen els xips ha patit un creixement exponencial, fet que ha provocat un augment de la complexitat dels processadors moderns i, per tant, de la dificultat de la programació eficient d’aquests sistemes. Per intentar solucionar-ho, s’han desenvolupat diversos models de programació; un exemple particular en són els models basats en tasques, que fan servir anotacions senzilles per definir treballs paral·lels dins d’una aplicació. La informació que hi ha al nivell dels sistemes en temps d’execució (runtime systems) associada amb aquests models de programació ofereix un gran potencial a l’hora de millorar el disseny del maquinari. D’altra banda, les limitacions tecnològiques fan que la llei de Moore pugui deixar de complir-se properament, per la qual cosa calen nous paradigmes per mantenir les tendències actuals en la millora de rendiment. L’objectiu principal d’aquesta tesi és aprofitar els coneixements que el runtime System té d’una aplicació paral·lela per millorar el disseny de la jerarquia de memòria dins el xip. L’acoblament del runtime system i el microprocessador permet millorar el disseny del maquinari sense malmetre la programabilitat d’aquests sistemes. La primera contribució d’aquesta tesi consisteix en un conjunt de polítiques d’inserció a les memòries cau (cache memories) compartides d’últim nivell que aprofita informació sobre tasques i les dependències de dades entre aquestes. La intuïció que hi ha al darrere d’aquesta proposta es basa en el fet que els fils d’execució paral·lels mostren diferents patrons d’accés a la memòria; fins i tot dins el mateix fil, els accessos a variables diferents sovint segueixen patrons diferents. Les polítiques que s’hi proposen insereixen línies de la memòria cau a diferents ubicacions lògiques en funció dels tipus de dependència i de tasca als quals correspon la petició de memòria. La segona proposta optimitza l’execució de les reduccions, que es defineixen com un patró de programació que combina dades d’entrada per aconseguir la variable de reducció com a resultat. Això s’aconsegueix mitjançant una tècnica assistida pel runtime system per dur a terme reduccions en la jerarquia de la memòria cau del processador, amb l’objectiu que la proposta sigui aplicable de manera universal, sense dependre del tipus de la variable a la qual es realitza la reducció, la seva mida o el patró d’accés. A nivell de programari, es realitza una extensió del model de programació per facilitar que el programador especifiqui les variables de les reduccions que usaran les tasques, així com el nivell de memòria cau desitjat on s’hauria de realitzar una certa reducció. El compilador font a font (compilador source-to-source) i el runtime system s’amplien per traduir i passar aquesta informació al maquinari subjacent. A nivell de maquinari, les memòries cau privades i compartides s’equipen amb unitats funcionals i la lògica corresponent per poder dur a terme les reduccions a la pròpia memòria cau, evitant així moviments de dades innecessaris entre el nucli del processador i la jerarquia de memòria. La tercera contribució proporciona un esquema de priorització assistit pel runtime System per peticions de memòria dins de la jerarquia de memòria del xip. La proposta es basa en la noció de camí crític en el context dels codis paral·lels i en el fet conegut que l’acceleració de les tasques que formen part del camí crític redueix el temps d’execució de l’aplicació sencera. En el context d’aquest treball, la criticitat de les tasques s’observa al nivell del seu tipus ja que permet que el programador les indiqui mitjançant anotacions senzilles. L’acceleració de les tasques crítiques s’aconsegueix prioritzant les corresponents peticions de memòria dins el microprocessador

Ispitivanje efikasnosti različitih dodataka hrani za životinje na proizvodne rezultate brojlera tretiranih T-2 toksinom

Experiment was conducted on 160 one-day-old broiler chicks 'Ross' proveniention during 21 day. This research was done with the aim to investigate performances of broilers exposed to the relatively small amount of T-2 toxin (2 mg/kg) and the possibility of prevention and/or alleviating its adverse effects by using various feed additives. Results showed negative consequences of T-2 toxin on body weight, weight gain, feed: gain ratio. All used feed additives in the concentration of 0.2% in feed: inorganic (Minazel-plus, Mz) and organic (Mycosorb, Ms) adsorbents, as well as mixed adsorbent (Mycofix-plus, Mf) mostly alleviated negative effects of T-2 toxin.Rezultati istraživanja, koje je urađeno sa ciljem da se ispitaju proizvodni rezultati brojlera izloženih relativno malim količinama T-2 toksina (2 mg/kg), kao i i mogućnost sprečavanja i/ili ublažavanje njegovih štetnih posledica posledice upotrebom različitih dodataka hrani za životinje, pokazali su negativne posledice T-2 toksina na telesnu masu, prirast i konverziju hrane. Svi primenjeni dodaci u koncentraciji od 0,2% u hrani: neorganski (Minazel plus, MZ), organski (Mycosorb, MS), kao i mešoviti adsorbens (Mycofix plus, MF) najvećim delom su ublažili negativne efekte T-2 toksina. Pa ipak, kao najefikasniji pokazao se mešoviti adsorbent. Naime, očigledno je da tokom svog metabolizma BBSH 797, kao sastavni deo Mycofix-a, proizvodi enzime de-epoksidaze koji degradiraju trihotecene selektivnim uništavanjem njihove toksične 12,13-epoksi grupe. Kako je poznato da je 12,13-epoksi prsten trihotecena odgovoran za njegovu toksičnost, dodavanje specifičnih enzima (de-epoksidaza) posledično dovodi i do značajnog smanjenja toksičnosti. Na ovaj način je mešoviti adsorbent najviše ublažio štetno dejstvo T-2 toksina na proizvodne rezultate brojlera

OPEN ARCHITECTURE PLATFORMS FOR THE CONTROL OF ROBOTIC SYSTEMS AND A PROPOSED REFERENCE ARCHITECTURE MODEL

This paper presents advantages of using open architecture for the real-time control of robot manipulators, parallel kinematics machine tools and other multi-axis machining systems. In order to increase their competitiveness, companies need to follow the global economy requirements. The constant incorporation of new technologies into existing controllers and reduction in the development time and costs are the main objectives. An open architecture control (OAC) concept appears as a solution to deal with these requirements. This article explains the rationale for the development of OAC systems, presents the major international activities which propose various approaches to OACs and a series of controllers that have been developed using this design philosophy at the Lola Institute

OPEN ARCHITECTURE PLATFORMS FOR THE CONTROL OF ROBOTIC SYSTEMS AND A PROPOSED REFERENCE ARCHITECTURE MODEL

This paper presents advantages of using open architecture for the real-time control of robot manipulators, parallel kinematics machine tools and other multi-axis machining systems. In order to increase their competitiveness, companies need to follow the global economy requirements. The constant incorporation of new technologies into existing controllers and reduction in the development time and costs are the main objectives. An open architecture control (OAC) concept appears as a solution to deal with these requirements. This article explains the rationale for the development of OAC systems, presents the major international activities which propose various approaches to OACs and a series of controllers that have been developed using this design philosophy at the Lola Institute

Procedure for definition of end-effector orientation in planar surfaces robot applications

Razvoj moćnih metoda za programiranje robota koje su ujedno i korisnički prilagođene je tema značajnih istraživanja u robotskoj zajednici. Radi olakšavanja programiranja robota, pojavljuje se ideja o razvoju standardnih procedura za programiranje najčešće prisutnih robotskih zadataka, a koje se mogu univerzalno lako upotrebiti kao gotov deo (ready-made) korisničkog programa. Važna klasa aplikacija industrijskih robota podrazumeva kretanje hvatača (end-effector) u paralelnim ravnima. U ovom radu je prikazan razvoj procedure jezika za programiranje robota koja služi za određivanje normale ravni objekta u odnosu na koordinatni sistem od značaja, kao i osnova procedure za automatizovani postupak programiranja orijentacije hvatača u odnosu na ravan objekta. Ova procedura se može koristiti kao integralni deo task oriented metoda programiranja robota, a takođe kao i procedura eksplicitnog robotskog programskog jezika, i ilustrovana je kroz praktični primer na robotu Lola 15.Design of user-friendly and at the same time powerful robot programming methods is the subject of significant efforts undertaken by the international robotics community. For the purpose of facilitating robot programming, with regard to the most common present-day applications in industry, it would be useful to develop programming procedures for frequently used manipulator tasks which could be easily implemented and used as ready-made application software. Important class of industrial robot applications involves end-effector trajectories in planar surfaces. Development of robot programming language procedure intended for determination of object plane normal with respect to frame of interest, as well as programming of end-effector orientation is presented in this paper. This procedure can be used as integral part of task oriented robot programing applications as well as a procedure for explicit programming languages, and it is illustrated in practical example with the robot Lola 15

Procedure for definition of end-effector orientation in planar surfaces robot applications

Razvoj moćnih metoda za programiranje robota koje su ujedno i korisnički prilagođene je tema značajnih istraživanja u robotskoj zajednici. Radi olakšavanja programiranja robota, pojavljuje se ideja o razvoju standardnih procedura za programiranje najčešće prisutnih robotskih zadataka, a koje se mogu univerzalno lako upotrebiti kao gotov deo (ready-made) korisničkog programa. Važna klasa aplikacija industrijskih robota podrazumeva kretanje hvatača (end-effector) u paralelnim ravnima. U ovom radu je prikazan razvoj procedure jezika za programiranje robota koja služi za određivanje normale ravni objekta u odnosu na koordinatni sistem od značaja, kao i osnova procedure za automatizovani postupak programiranja orijentacije hvatača u odnosu na ravan objekta. Ova procedura se može koristiti kao integralni deo task oriented metoda programiranja robota, a takođe kao i procedura eksplicitnog robotskog programskog jezika, i ilustrovana je kroz praktični primer na robotu Lola 15.Design of user-friendly and at the same time powerful robot programming methods is the subject of significant efforts undertaken by the international robotics community. For the purpose of facilitating robot programming, with regard to the most common present-day applications in industry, it would be useful to develop programming procedures for frequently used manipulator tasks which could be easily implemented and used as ready-made application software. Important class of industrial robot applications involves end-effector trajectories in planar surfaces. Development of robot programming language procedure intended for determination of object plane normal with respect to frame of interest, as well as programming of end-effector orientation is presented in this paper. This procedure can be used as integral part of task oriented robot programing applications as well as a procedure for explicit programming languages, and it is illustrated in practical example with the robot Lola 15

Configuring EMC2 for programming and simulation multi axis machine tools in python virtual environment

U radu će biti predstavljen način simulacije višeosnih mašina alatki u open-source softverskom paketu EMC2. Kroz primer vertikalnog strugarskog obradnog centra i šestoosnog robota, biće prikazan način integrisanja funkcija indirektne i direktne kinematike, način modelovanja komponenti mašine alatke u Python okruženju EMC2, njihovo povezivanje u celinu mašine i animacija u funkciji NC programa obrade.The paper presents simulation procedure of multi axis machine tools in open-source software system EMC2. Simulation results are given on the example of vertical turning machining center and 6-dof robot, using Python programming language

EMC software based CNC development concept for machine tools with specific configuration

Ključne teme istraživanja i razvoja u istraživačkim institucijama i vodećim industrijama visokorazvijenih zemalja je razvoj kvalitetnih CNC upravljačkih sistema na osnovi open-source softverskih paketa. Ovaj pravac istraživanja je vrlo aktuelan širom sveta, pa i kod nas. U radu su predstvaljena istraživanja iz sveta, dosadašnji rezultati koji su ostvareni na mašinama kod nas i pravci budućih istraživanja u ovom domenu.The key issue in R&D in research instituties and leading indistries of developed countries is the development of CNC control systems based on open source softwares. This research lead is up todate world wide, as well as in our country. This paper presents wordwide research, results obtained on our machines as well as directions for futur research in this area.Tehnički urednici: Prof. dr Petar B. Petrović, Mr Mihajlo Popović, Mr Živana Jakovljevi

Concept of 5-axes vertical turning machining center control using open architecture control system

Do pre desetak godina CNC kao specijalizovan računarski sistem je bio neprikosnoven industrijski računar za upravljanje mašinama alatkama. Otvorena PC arhitektura dizajnirana za industrijske aplikacije polako i vrlo temeljno potiskuje specijalizovane CNC sisteme sa tržišta. Iako se veliki proizvođači CNC sistema bore da održe korak i ulažu velika sredstva u razvoj, arhitektura i performanse, a posebno cena, prosečnog industrijskog PC-a nema konkurencijy. To je razlog što se sve više ljudi u svetu okreće razvoju softverski orijentisanih CNC sistema, za šta se kao osnova koristi PC platforma i Linux operativni sistem sa real-time ekstenzijom. Dakle, PC kao osnova, odgovarajuće PC interfejs kartice i softverski orijentisani CNC čine tri glavne celine upravljačke jedinice otvorene arhitekture (OAC - Open architecture control), na svetskom tržištu.Up to 10 years ago, CNC as specialized computer system was the only industrial computer for machine tools control. Open PC architecture designed for industrial applications easily and very thoroughly suppresses specialized CNC systems from market. Although huge manufacturers of CNC systems invest in development, architecture and performances, and especially price of average PC has no competition. This is the main reason that more and more people turns to development of software oriented CNC systems which, as a basis, use PC platform and Linux OS with real-time extension. Hence, PC as basis, corresponding PC interface cards and software oriented CNC make three main entities of open architecture control unit (OAC - Open architecture control) in world market.Glavni i odgovorni urednik: Prof.dr Ljubodrag Tanovi

Development of the algorithms for smoothing of trajectories of a roll and pitch axis of a centrifuge motion simulator

Centrifuge motion simulator (CMS) is a training device used for simulation of high onset rates of accelerations and high sustained accelerations acting on a pilot during challenging flights of modern combat aircraft. The CMS device has three degrees of freedom. Training profiles in the CMS require achieving of desired linear profiles of G-load with variable programmed onset rates. The desired piecewise linear G-load profiles could lead to very demanding joint trajectories for which achievement very powerful motors would have to be in use. In order to lessen the motor load, to provide better tracking capabilities of controllers, and to avoid vibrational problems, while in the same time achieving desired acceleration profiles, trajectory shaping techniques have to be considered. In this paper, development of the algorithms for smoothing of motions of the CMS’s second (roll) and the third (pitch) joint is presented. Smoothing of the absolute value of the acceleration acting on a pilot is compared to smoothing of the CMS trajectories in joint space