Project - AICS Research Division

50 Pages·2013·11.6 MB·English

by  Masaaki Terai

The  42th  AICS  Cafe  /  Workshop  room  (6th  floor)
An Introduction to K-scope
for Application Performance Improvement
August  30,  2013
Masaaki  Terai
Research  &  Development  Scientist
RIKEN  AICS,  Software  Development  Team
Operations  and  Computer  Technologies  Div.
Outline
• Background
• Design
• Overview  of  Usage  and  Features
-­‐ Introduction  to  Feature1:  Interface
-­‐ Introduction  to  Feature2:  Static  Program  Analysis
-­‐ Introduction  to  Feature3:  Visualization  of  Profile  Result  for  the  K
• Recent  Work
• Demonstration
2
Background
3
Team  Missions
• Software  development  team,  operations  and  computer  technologies  div.
• Missions
-­‐ Performance  tuning  for  applications
-­‐ Performance  estimation  and  evaluation  (include  system  examination)
-­‐ Various  enhancement  and  feedback  (compiler,  profiler,...,  tools)
-­‐ K-­‐support  desk  (as  a  part  of  operation)
-­‐ Maintenance  for  private  servers
4
HPC  Applications
• Examples  for  application  from
-­‐ Target  applications  in  development  of  the  K
-­‐ AICS
-­‐ Others
• Below  statistics  are  estimated  with  grep  and  wc.
Application Language Number  of  Files Line  of  Codes
NICAM Fortran  90/77 204 302285
Seism3D Fortran  90/77 41 15921
RSDFT Fortran  90/77 373 197670
PHASE Fortran  90/77 393 243327
Front  Flow/Blue FORTAN  77 233 60703
Lattice  QCD Fortran  90 146 63971
NwChem* Fortran  77 256 75030
SCALE-­‐LES Fortran  90/77,  C 196 133806
Para-­‐TCCI Fortran  90 44 42607
*  This  is  a  part  of  whole  program.
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Story  and  Problem
• Familiar  story
-­‐ Actually  a  few  applications  are  simple  by  refactoring  or  
scrap  and  build.
-­‐ However  almost  the  applications  are  often  destined  to  
bloat  with  time.
-­‐ The  application  has  complex  and  a  number  of  source  
codes  to  perform  detailed  simulation  on  the  background  
of  progress  in  hardware  performance  and  development  
environment.
• Specific  story  in  HPC
-­‐ We  have  little  to  no  non-­‐commercial  code  reading  tools  for  Fortran.
• Possible  problems
-­‐ We  receive  those  applications  to  improve  the  performance.
-­‐ An  engineer  except  for  primary  developer  dedicates  time  and  energy  to  understand  
source  code  before  the  work.
-­‐ Reduction  in  productivity
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Tools  (Static  Code  Analysis)
al They  are  simple.  It’s  up  to  you  to  benefit  your  work.
n- n
e o
v ti
n
o grep,  find,  diff,  vim,  emacs  (+  sed,  awk,  perl…)  
C
Enhancements with Software engineering
(Static Error Detection/Assisted Coding and Maintenance/Optimization/Metrics/Project Management)
• FortranLint*  (Cleanscape)
• NAG  Fortran  Compiler*  (NAG)
• Fujitsu  Visual  Analyzer*  (Lahey  Computer  Systems)
• plusFORT*  (Polyhedron)
n
+ a • FORCHECK*  (Leiden  University)
+ a tr
/C av or • DEEP  (Pacific-­‐Sierara  Research,  1998)
C J F
R.  F.  Fowler  and  C.  Greenough,  “So5ware  Quality  Assurance  for  Fortran  90  -­‐  A  Survey  of  Available  Tools”,  Technical  Report  (1999).
Conglomerate + Multi Platform
• Understand2.0*  (Scientific  Toolworks)
• Photran  (University  of  Illinois)  *eclipse  plugin
Most  of  the  tools  are:
-­‐ Commercial
-­‐ Not  for  Performance  Improvement
-­‐ Stopped  development  or  no  longer  activity
-­‐ Only  support  Windows  and  UNIX/Linux
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Tuning  as  Application  Development
One  target,  some  approaches
Target
Performance  
• Application  developer • System  software  engineer
Improvement
• Computational  scientist • Computer  scientist
Algorithm
Compiler
(Solver)
Hand-­‐coded  optimization
Implementation
Semi-­‐automatic  optimization
Tool’s  target  user
• Performance  improvement  engineer
• Application  developer  /  Maintainer
• Software  engineer
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Performance  Improvement
• Performance  Improvement  (=  tuning)
-­‐ Single  processor  tuning  x  Parallel  performance  tuning
The  system  is  hierarchical.
Today’s  topic
System Board
CPU (=compute node) Rack Image of 3D torus of Tofu
interconnect
864 racks
(=82,944 compute nodes)
8
on the K computer
9
Trial  and  Error
• Tuning
-­‐ Trial  and  error
coding/
Compiling Execution Evaluation
tuning  
-­‐ Systematic  approach  based  on  cause  and  
effect  with  tools
-­‐ The  execution  system  consists  of  many  layers  
such  as  application,  compiler,  CPU  and  so  on.
-­‐ Major  parts  of  them  are  black  box  for  a  
common  engineer.
-­‐ Tuning  is  gray  area  between  heuristic  and  
systematic
-­‐ Like  a  puzzle
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