tính toán song song thoại nam parallelprocessing 10 parallel paradigm programming model sinhvienzone com

Si nh Vi en Zo ne C om Parallel Paradigms & Programming Models SinhVienZone.com Thoai Nam https://fb.com/sinhvienzonevn om Outline programming paradigms  Programmability Issues  Parallel programming models – nh Vi en – Implicit parallelism Explicit parallel models Other programming models Si – Zo ne C  Parallel https://fb.com/sinhvienzonevn Khoa Khoa học Kỹ thuật Máy tính - Đại học Bách Khoa TP.HCM SinhVienZone.com -2- Parallel Programming Paradigms – Commonly-used algorithmic paradigms – – – – – – nh Vi en  ne – Design a parallel program Structure the algorithm of a parallel program Deploy/run the program on a parallel computer system Zo – C om Parallel programming paradigms/models are the ways to Phase parallel Synchronous and asynchronous iteration Divide and conquer Pipeline Process farm Work pool Si  https://fb.com/sinhvienzonevn Khoa Khoa học Kỹ thuật Máy tính - Đại học Bách Khoa TP.HCM SinhVienZone.com -3-  ne Zo – How much easy to use this system for developing and deploying parallel programs How much the system supports for various parallel algorithmic paradigms nh Vi en – C The programmability of a parallel programming models is Programmability is the combination of – – – Structuredness Generality Portability Si  om Parallel Programmability Issues https://fb.com/sinhvienzonevn Khoa Khoa học Kỹ thuật Máy tính - Đại học Bách Khoa TP.HCM SinhVienZone.com -4- A program is structured if it is comprised of structured constructs each of which has these properties – The structuredness mostly depends on – – The programming language The design of the program Si  Zo – Is a single-entry, single-exit construct Different semantic entities are clearly identified Related operations are enclosed in one construct nh Vi en – ne C  om Structuredness https://fb.com/sinhvienzonevn Khoa Khoa học Kỹ thuật Máy tính - Đại học Bách Khoa TP.HCM SinhVienZone.com -5- – ne Zo – For any program Q in D, we can write a program P in C Both P & Q have the same semantics P performs as well as or better than Q nh Vi en – C A program class C is as general as or more general than program class D if: Si  om Generality https://fb.com/sinhvienzonevn Khoa Khoa học Kỹ thuật Máy tính - Đại học Bách Khoa TP.HCM SinhVienZone.com -6- Portability om A program is portable across a set of computer system if it can be transferred from one machine to another with little effort Portability largely depends on –  Zo The language of the program The target machine’s architecture nh Vi en – Levels of portability Users must change the program’s algorithm Only have to change the source code Only have to recompile and relink the program Can use the executable directly Si  ne C  https://fb.com/sinhvienzonevn Khoa Khoa học Kỹ thuật Máy tính - Đại học Bách Khoa TP.HCM SinhVienZone.com -7- Widely-accepted programming models are – C ne – Zo – Implicit parallelism Data-parallel model Message-passing model Shared-variable model ( Shared Address Space model) nh Vi en – Si  om Parallel Programming Models https://fb.com/sinhvienzonevn Khoa Khoa học Kỹ thuật Máy tính - Đại học Bách Khoa TP.HCM SinhVienZone.com -8- om Implicit Parallelism The compiler and the run-time support system automatically exploit the parallelism from the sequential-like program written by users  Ways to implement implicit parallelism – nh Vi en – Parallelizing Compilers User directions Run-time parallelization Si – Zo ne C  https://fb.com/sinhvienzonevn Khoa Khoa học Kỹ thuật Máy tính - Đại học Bách Khoa TP.HCM SinhVienZone.com -9- A parallelizing (restructuring) compiler must  C ne Zo – Performs dependence analysis on a sequential program’s source code Uses transformation techniques to convert sequential code into native parallel code nh Vi en – Dependence analysis is the identifying of – – Data dependence Control dependence Si  om Parallelizing Compiler https://fb.com/sinhvienzonevn Khoa Khoa học Kỹ thuật Máy tính - Đại học Bách Khoa TP.HCM SinhVienZone.com -10- Users help the compiler in parallelizing by Zo  User is responsible for ensuring that the code is correct after parallelization Example (Convex Exemplar C) nh Vi en  C – Providing additional information to guide the parallelization process Inserting compiler directives (pragmas) in the source code ne – #pragma_CNX loop_parallel for (i=0; i