HPUX Debuggers and Profilers

1
HP-UX Debuggers and Profilers

• see http//www.hp.com/go/wdb
• http//www.hp.com/go/hpcaliper

2
WDB/GDB Debugger

• has replaced all previous debuggers on HP-UX
  (xdb, dde) for both PA-RISC and IPF.
• Choice of user interfaces
• gdb for command line use
• vdb runs gdb in a split terminal window like xdb
• wdb is a Motif GUI on top of gdb
• Location /opt/langtools/bin

3
HP WDB Features

• Support for 32 bit and 64 bit data models and all
  languages
• Debugs optimized code up to O2
• Support for pthreads and consequently OpenMP
• HW watchpoints
• Memory checking (currently only on PA-RISC)
• Array browsing
• User definable buttons
• Basic MPI supportAn extra wdb instance is
  started for every MPI process, so this is usable
  up to maybe 4 processes.read man mpidebug for
  MPI debugging instructions

4
Debug Preparation

• On PA-RISC
• Compile and link with gDebug information is in
  the executable
• No support for 64 bit optimized programs. Compile
  at O0
• 32 bit programs can be debugged at O1 (good) and
  O2 (limited)
• Trouble with NFS mounted executables. Try to work
  on local disk.
• On IPF
• Compile and link with gDebug information stays
  in the object filesCompile with noobjdebug for
  debug info in the executable
• Both 32 bit and 64 bit programs can be debugged
  at O1 (good) and O2 (limited).Note that
  register variables cant be viewed at O2

5
Profiling with CALIPER (1)

• Highlights
• Dynamic instrumentation requires no preparation
  for executables
• All Itanium PMU counters are available for event
  counts
• Supports multithreaded execution
• Wish List
• Support for MPI profiling and 3D charts for
  parallel profiles
• Better source line mapping
• Two modes of operation
• Low intrusion hardware counters based
  measurements
• Sample based/ clock driven profiling
• Measure execution cycles, cache misses, branch
  mispredictions, etc.
• Dynamic binary instrumentation for precise counts
• e.g. function call graph, basic block arc counts
  accurately
• event driven (Gprof or Cxperf type)

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Profiling with CALIPER (2)

• Usage/opt/caliper/bin/caliper config-file
  ltoptionsgt ltprogramgt ltargsgt
• Common config-files (many more available)
• cgprof call graph profile (intrusive)
• sample_ip sampling profile like PROSPECT (non
  intrusive)
• pbo create flow.data for PBO (requires O1
  build)
• dcache_miss cache metrics
• Output options (many more available )
• -oltfilegt single file ASCII output
• --htmlltdirgt HTML output into directory

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Profiling with CALIPER (3) measurements

• type config_file comments
• optimization pbo black box
• total measurements total_cpu exact
  totals, no impact
• sample measurements branch_prediction
  sampled details, low
• dicache_miss impact
• ditlb_miss
• sample_cpuip
• precise measurements arc_count exact
  details, high
• func_count impact
• func_cover
• hybrid cgprof sampled exact, high
• impact

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Profiling with CALIPER (4) measurement strategy

• if automatic optimization
• if call graph profile
• if correctness testing
• determine what takes time
• determine where event happens
• determine when event happens

• Pbo
• cgprof
• arc_count, func_count, func_cover
• total_cpu w/ various events
• branch_prediction,dicache_miss,
  ditlb_miss,sample_ip w/ select trigger
• sample_cpu w/ select trigger

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Profiling with CALIPER (5)

• All PMU counters of ITANIUM can be used with
  CALIPER config files. See the list in
  /opt/caliper/doc/text/itanium2_cpu_counters
• For counter description see the Intel Itanium-2
  Processor Reference Manual For Software
  Development and Optimisation
• Measure total of Flops, Underflows and Clock
  Cycles
• caliper total_cpu global-counters\
  FP_OPS_RETIRED, FP_FLUSH_TO_ZERO, CPU_CYCLES \
  ltprogramgt ltargsgt
• Measure of MFlops per subroutine
• caliper sample_ip \ sampling-counterFP_O
  PS_RETIRED,,1000000 \ ltprogramgt ltargsgt

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total_cpu example

• caliper total_cpu crafty.O3 lt crafty.in
• HP Caliper Total CPU Counts Report
• Target Application
• Program /home/daveb/crafty.O3
• Invocation crafty.O3
• Process ID 8859 (started by Caliper)
• Start time 075639 AM
• End time 075643 AM
• Last modified June 01, 2002 at 0756 AM
• Processor Information
• Machine name longsp8
• Number of processors 2
• Processor type Itanium2
• Processor speed 798 MHz

• Report Help
• Use the caliper option --info to append help to
  this report,
• or see /opt/caliper/doc/text/total_cpu.help.
• -----------------------------------------
• Counter Priv. Mask Count
• -----------------------------------------
• INST_DISPERSED 8 (USER) 5029272413
• NOPS_RETIRED 8 (USER) 690880642
• CPU_CYCLES 8 (USER) 3140760527
• -----------------------------------------
• CPI
• 0.6245 CPU_CYCLES / INST_DISPERSED
• Useful CPI
• 0.7239 CPU_CYCLES / (INST_DISPERSED -
  NOPS_RETIRED)

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branch_prediction (html) example
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More Profiling Tools ...

• TUSC aka TRUSS is a system call tracer. Not
  supported but usable and robust. Get it here
• ftp//ftp.cup.hp.com/dist/networking/tools
• Visual Threads thread tracer was recently ported
  from Tru64 to HP-UX (IPF only).Currently in beta
  status. See
• http//shvlhd.zko.cpqcorp.net/ThreadTools
• GlancePlus, the official HP-UX system monitor
  with GUI offers detailed statistics and graphs on
  all relevant system resources like CPUs, Memory,
  Swap, Disks, Network, ProcessesInvocation
  /opt/perf/bin/gpm