IBM Haifa Labs © 2005 IBM Corporation Performance Tools developed in IBM Haifa Gad Haber

IBM Haifa Labs © 2005 IBM Corporation 2 HRL Performance Tools  FDPR-Pro  Feedback-based optimizer operating on binary executable files  Part of the AIX 5L  Available on Linux on Power via alphaworks  Under development for  Mac OS X – to be available soon via alphaworks  z/OS  CodeAnalyzer  Eclipse plugin tool for analyzing executable files  Under development  To be added as part of the Performance Work Bench (PerfWB)  BProber  Utility for instrumenting binary executable files  Under development  ESTO  Utility for identifying the optimal set of optimization options  Under development

IBM Haifa Labs © 2005 IBM Corporation FDPR-Pro Feedback Directed Program Restructuring

IBM Haifa Labs © 2005 IBM Corporation 4 FDPR-Pro - Feedback Directed Program Restructuring  Using a global view of the entire program  Operating on the executable file after linkage  These properties enable FDPR-Pro to do:  Global Code Reordering  Inter Procedure Boundaries Optimizations  Static Data Rearrangement  Constant Area Rearrangement  Data Prefetching  Examples of FDPR-Pro additional optimizations:  Usage of Branch Tables  Usage of TOC load instructions  More..

IBM Haifa Labs © 2005 IBM Corporation 5 Method  Phase 1: Code instrumentation  Basic block level  Phase 2: Profile information gathering  Selection of "right" input set (representative workload)  Accumulation over several input sets  Phase 3: Global Code & Data Optimizations  Complements the compiler

IBM Haifa Labs © 2005 IBM Corporation 6 FDPR-Pro Optimization Options  -RCReorder Code  -bfBranch folding  -bpBranch prediction bit setting  -alignCode alignment  -nop Eliminate nop instructions  -uceUnreachable code elimination  -hco_resched Hot/Cold instruction scheduling  -RD, -build_dcg Static data reordering  -tocload, -reduce_toc Tocload optimizations  -si, -ipht, -ihf, -isf Aggressive function inlining options  -ptrgl_optimization Optimize function calls via pointers  -dcbt_optimizationInject data prefetching instructions  -link_reg_optimization Eliminate stores/restore of link register  -volatile_regsEliminate stores/restores using available volatile regs  -killed_regs Eliminate stores/restores of killed registers  -load_after_store Separate between frequent load and store to same address  -loop_unroll Loop unrolling  -stack_opt Reduce stack frame size of Hot functions  -dceDead code elimination

IBM Haifa Labs © 2005 IBM Corporation CodeAnalyzer

IBM Haifa Labs © 2005 IBM Corporation 8 CodeAnalyzer - Motivation  Architectures are becoming more complex  Using only hardware simulators to detect information about potential performance bottlenecks in a given program is hard  There is a need for performance tools that can statically analyze and visualize programs for a platform design, to be used by:  Hardware architects  Compiler writers  Application developers

IBM Haifa Labs © 2005 IBM Corporation 9 CodeAnalyzer  CodeAnalyzer is an eclipse plugin which performs comprehensive static analysis on given executable files and DLLs  Relies on the FDPR-Pro tool for the analysis phase  CodeAnalyzer displays the analyzed information together with profiling data collected by:  tprof  FDPR-Pro  The code is then colored according to:  Frequency counters - gathered by FDPR-Pro  Hardware event ticks - gathered by tprof

IBM Haifa Labs © 2005 IBM Corporation 10 CodeAnalyzer – (continued)  Provides several views of the input binary  Assembly instructions  Basic blocks  Procedures  CSECT modules  control flow graph  Hot loops  Call graph  Annotated source code  Dispatch group formation  Pipeline slots and functional units

IBM Haifa Labs © 2005 IBM Corporation 11 CodeAnalyzer – (continued)

IBM Haifa Labs © 2005 IBM Corporation 12 CodeAnalyzer – (continued)

IBM Haifa Labs © 2005 IBM Corporation 13 CodeAnalyzer – (continued)

IBM Haifa Labs © 2005 IBM Corporation 14 CodeAnalyzer – (continued)

IBM Haifa Labs © 2005 IBM Corporation 15 CodeAnalyzer – (continued)

IBM Haifa Labs © 2005 IBM Corporation 16 CodeAnalyzer – (continued)

IBM Haifa Labs © 2005 IBM Corporation 17 CodeAnalyzer – (continued)

IBM Haifa Labs © 2005 IBM Corporation 18 CodeAnalyzer – (continued)

IBM Haifa Labs © 2005 IBM Corporation 19 CodeAnalyzer – Performance Comments  Performance comments displayed by CodeAnalyzer  Comments which do not require profiling  Pipeline stalls for the Power architecture  Unreachable code and non-used data  Profile-based comments  Non-variant instructions within Hot loops  Hot function calls proceeded by overwriting non-volatile registers  Hot saves and restores of registers which could be relocated to cold spill areas  Hot instructions that could be scheduled to colder areas in the code  Removable hot branches  Hot direct unconditional branches  Hot direct conditional branches that are taken, which have a colder fallthru  Hot call sites that are appropriate candidates for function inlining  Hot call sites that are appropriate for function specialization  Hot loops that are appropriate for loop unrolling  Hot TOC load instructions that can be replaced by immediate add instructions

IBM Haifa Labs © 2005 IBM Corporation Performance Workbench (PerfWB)

IBM Haifa Labs © 2005 IBM Corporation 21 PerfWB  CodeAnalyzer is part of the Performance Workbench (PerfWB) utility  PerfWB is a collection of eclipse plugins that provide performance monitoring, tuning and analysis  PerfWB consists of the following eclipse plugins:  ProcMon - system-level monitoring tool for displaying system state and for monitoring running processes and threads  E-Tune - visualizer of feedback information produced by tprof  CodeAnalyzer – performance analyzer of executables and DLLs

IBM Haifa Labs © 2005 IBM Corporation 22 ProcMon

IBM Haifa Labs © 2005 IBM Corporation 23 E-Tune with CodeAnalyzer