12014-06-27

Many-SC Programming Model

Jaejin Lee

Center for Manycore Programming

Seoul National University

2014.06.27

2014-06-27 2

Schedule for the first yearSchedule (13/11/11~14/11/10)

1 2 3 4 5 6 7 8 9 10 11 12

1 Developing a low-level communication library

2 Developing a threading library

3 Developing a software SVM

4Verification and performance analysis of the low-level communication library and the software SVM on Chundoong

Interim report

Final report

6/27

2014-06-27 3

Cluster

The Structure of the Many-SC

Core Core

Core Core

Cluster

Core Core

Core Core

Cluster

Core Core

Core Core

Cluster

Core Core

Core Core

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The Structure of Typical Cluster Systems

Node

Core Core

Core Core

Node

Core Core

Core Core

Node

Core Core

Core Core

Node

Core Core

Core Core

Interconnection network

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Developing a Low-level Communication Library

• Many-SC• Cache coherence protocol

• Works between cores in a cluster

• Does not work between cores in different clusters

• It is very similar to the typical cluster systems

• Plan• Developing a low-level communication library for typical cluster systems

• Apply this to the Many-SC

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Low-level Communication Library

• Provide high-level APIs similar to MPI• The API functions are optimized for SnuCL

• Use RDMA internally

• Some API functions

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SnuCL

• An OpenCL framework for heterogeneous clusters• Platform layer + runtime + kernel compiler

• Freely available, open-source software • Supports OpenCL 1.2

• Passed most of OpenCL conformance tests

• Supports x86 CPUs, ARM CPUs, AMD GPUs, NVIDIA GPUs, Intel Xeon Phi coprocessors (from July, 2013)

• With SnuCL, an OpenCL application written for a single operating system instance runs on a heterogeneous cluster without any modi-fication

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The Structure of SnuCL

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Replacing Communication Library

Hardware

MPI

SnuCL

OpenCL Applications

Hardware

Low-level commu-nication library

SnuCL

OpenCL Applications

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Performance

4KB 8KB 16KB 32KB 64KB 128KB 256KB 512KB 1MB90%

95%

100%

105%

110%

115%

120%

SnuCL+MPI SnuCL+Low-level

Sp

ee

du

p

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Developing Thread Library

• Provide a subset of POSIX thread API functionsName Description

int pthread_create(pthread_t *thread,const pthread_attr_t *attr, void *(*start_routine)(void *),

void *arg);

Starts a new thread in the calling process

void pthread_exit(void *status); Terminate calling thread

int pthread_join(pthread_t thread, void **status); Join with terminated thread

pthread_t pthread_self(void); Obtain ID of the calling thread

int pthread_mutex_init(pthread_mutex_t *mutex,const pthread_mutexattr_t *attr);

Initialize a mutex

int pthread_mutex_destroy(pthread_mutex_t *mutex);

Destroy a mutex

int pthread_mutex_lock(pthread_mutex_t *mutex); Lock a mutexint pthread_mutex_unlock(pthread_mutex_t *mu-tex); Unlock a mutex

int pthread_barrier_init(pthread_barrier_t *restrict barrier,const pthread_barrierattr_t *restrict attr, unsigned count);

Initialize a barrier

int pthread_barrier_destroy(pthread_barrier_t *bar-rier); Destroy a barrier

int pthread_barrier_wait(pthread_barrier_t *barrier); Synchronize at a barrier

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Current Status and Future Plan

• Developing a low-level communication library• Done for cluster systems

• Need to be applied to the Many-SC

• Developing a threading library• Defining API functions is done

• Developing a software SVM for cluster systems• Need to implement

• Verification and performance analysis on Chundoong

132014-06-27

The End