MigThread : Heterogeneous Thread Migration

1
MigThread Heterogeneous Thread Migration

• Parallel and Distributed Computing Laboratory
• Department of Electrical and Computer Engineering
• Wayne State University, Detroit MI 48202

2
Idle Cycle Utilization on NOWs

• Research results from University of Maryland
• Equivalent Parallel Machine (EPM) computed by
  determining the size of the parallel machine that
  would be required to complete the execution in
  the same time

College Park (39)
Berkeley (52)
Wisconsin (277) EPM 29 (74)
EPM 25 (48)
EPM 91 (33)
Research indicated A large fraction of
workstations on NOWs are unused for a large
fraction of time
3
How to Harness Idle Cycles

• Process Migration basic migration scheme

• All-or-Nothing scenario the whole job occupies
  or evicts from computer completely
• Cannot handle parallel jobs well
• Such as Condor, DQS, CODINE, LSF

• One alternative In-Between scenario

• Foreign jobs do not evict completely right away
• Stay longer with lower priority to steal
  fine-grained idle cycles
• Such as Linger-Longer

• Thread Migration real In-Between
• Split computation into smaller units threads
• Migrate threads instead of the whole process
• Such as MigThread

Migrate all together, or, stay all together
Migrate all together, or, stay with low priority
Migrate individually, or, stay individually
Threads
Process
4
Implementation Styles

• Kernel-Level Migration Approaches
• Rely on distributed OS or network OS
• Good transparency and flexibility, high
  complexity
• MOSIX, Sprite
• User-Level Migration Approaches
• Libraries linked to applications at compile time
• Good transparency, less powerful
• Condor, Ariadne
• Application-Level Migration Approaches
• Parts of applications
• Good portability, less transparency
• Tui, Arachne

Application
Library
Kernel
5
How to Migrate Threads

• Pause computation
• Migrate the state of threads (from libraries or
  kernels)
• Pack, transfer, unpack, and restore thread state
  (process, computation, communication)
• Resume computation

migration
Threads
Threads
6
Adaptation Point

• Adaptation points possible migration points
• Too close need to avoid migration overhead
• Too far away insensitive to environments
• Sequential consistency model DSM
• Systems are in consistent state all the time
• Migration can take place at any time
• Relaxed consistency model DSM
• Systems are in consistent state only at
  synchronization points (barriers)
• Strings uses release consistency model
• Require pseudo-barriers (synchronize only
  progress, not the data)

7
Heterogeneous Thread Migration (HTM)

• MigThread HTM package

• MigThread HTM package

Designed and implemented in PDCL

• Abstract thread state up to language level
• Source-to-source translation

• No restriction on sizes of stacks and heap
  (user-level management)
• Virtually unlimited threads

• Support different Operating Systems
• All UNIX variants Linux, Solaris,
• Accept new OS in plug-and-play fashion (no
  setup required)

• Support different Operating Systems
• All UNIX variants Linux, Solaris,
• Accept new OS in plug-and-play fashion (no
  setup required)

• Support different Operating Systems
• All UNIX variants Linux, Solaris,
• Accept new OS in plug-and-play fashion (no
  setup required)
• Apply one-time receiver-makes-right instead of
  costly XDR (External Data Representation)

• Pointer casting
• Casting to/from integral types, such as integer,
  long

• Pointer casting
• Casting to/from integral types, such as integer,
  long

• Pointer casting
• Casting to/from integral types, such as integer,
  long
• Pointers in Union type
• Pointer detection

• Pointer casting
• Casting to/from integral types, such as integer,
  long
• Pointers in Union type
• Pointer detection
• Library calls
• Warning for possible memory leakage

• Pointer casting
• Casting to/from integral types, such as integer,
  long
• Pointers in Union type
• Pointer detection
• Library calls
• Warning for possible memory leakage
• State-carrying instructions
• Break down into serials of stateless or
  re-entrant sub-instructions

• Application-level Migration

• Application-level Migration

• Pointers in Union type
• Pointer detection

• Scalability

• Scalability

• Apply one-time receiver-makes-right instead of
  costly XDR (External Data Representation)

• Library calls
• Warning for possible memory leakage

• Portability
• (Heterogeneity)

• Portability
• (Heterogeneity)

• Translation on the fly
• Different byte orders
• Different data sizes and alignments
• Different address spaces
• Pointer translation
• Warning for incompatible migration

• State-carrying instructions
• Break down into serials of stateless or
  re-entrant sub-instructions

• Applicability
• (Migration Safety)

• Apply one-time receiver-makes-right instead of
  costly XDR (External Data Representation)

More programs become qualified for thread
migration.
8
Layout of MigThread

• MigThread consists of
• Preprocessor at compile time
• Runtime support module
• Preprocessor
• Input compiled C/C code
• Output Augmented C/C code ready for
  recompilation with common C/C compilers
• Runtime support module
• Linked as a library
• Exchange information with the augmented code at
  runtime
• User-level management of stack and memory

Compiled C/C code
MigThreads Preprocessor
Augmented C/C code
MigThreads Runtime Support Module
Workstation Pools
9
MigThread Package

• Working platforms All UNIX variants
• Website http//www.pdcl.eng.wayne.edu
• Team
• Prof. Vipin Chaudhary and Hai Jiang
• Sponsors Sun Microsystems and National Science
  Foundation (NSF)