Tool Visualizations, Metrics, and Profiled Entities Overview Adam Leko HCS Research Laboratory University of Florida

2 Summary Give characteristics of existing tools to aid our design discussions  Metrics (what is recorded, any hardware counters, etc)  Profiled entities  Visualizations Most information & some slides taken from tool evaluations Tools overviewed  TAU  Paradyn  MPE/Jumpshot  Dimemas/Paraver/MPITrace  mpiP  Dynaprof  KOJAK  Intel Cluster Tools (old Vampir/VampirTrace)  Pablo  MPICL/Paragraph

3 TAU Metrics recorded  Two modes: profile, trace Profile mode  Inclusive/exclusive time spent in functions  Hardware counter information  PAPI/PCL: L1/2/3 cache reads/writes/misses, TLB misses, cycles, integer/floating point/load/store/stalls executed, wall clock time, virtual time  Other OS timers (gettimeofday, getrusage)  MPI message size sent Trace mode  Same as profile (minus hardware counters?)  Message send time, message receive time, message size, message sender/recipient(?) Profiled entities  Functions (automatic & dynamic), loops + regions (manual instrumentation)

4 TAU Visualizations  Profile mode Text-based: pprof (example next slide), shows a summary of profile information Graphical: racy (old), jracy a.k.a. paraprof  Trace mode No built-in visualizations Can export to CUBE (see KOJAK), Jumpshot (see MPE), and Vampir format (see Intel Cluster Tools)

5 TAU – pprof output Reading Profile files in profile.* NODE 0;CONTEXT 0;THREAD 0: %Time Exclusive Inclusive #Call #Subrs Inclusive Name msec total msec usec/call , main() (calls f1, f5) ,001 15, f1() (sleeps 1 sec, calls f2, f4) ,001 15, main() (calls f1, f5) => f1() (sleeps 1 sec, calls f2, f4) ,003 10, f2() (sleeps 2 sec, calls f3) ,001 9, f1() (sleeps 1 sec, calls f2, f4) => f4() (sleeps 4 sec, calls f2) ,001 9, f4() (sleeps 4 sec, calls f2) ,003 6, f2() (sleeps 2 sec, calls f3) => f3() (sleeps 3 sec) ,003 6, f3() (sleeps 3 sec) ,001 5, f4() (sleeps 4 sec, calls f2) => f2() (sleeps 2 sec, calls f3) ,001 5, f1() (sleeps 1 sec, calls f2, f4) => f2() (sleeps 2 sec, calls f3) ,001 5, f5() (sleeps 5 sec) ,001 5, main() (calls f1, f5) => f5() (sleeps 5 sec)

6 TAU – paraprof

7 Paradyn Metrics recorded  Number of CPUs, number of active threads, CPU and inclusive CPU time  Function calls to and by  Synchronization (# operations, wait time, inclusive wait time)  Overall communication (# messages, bytes sent and received), collective communication (# messages, bytes sent and received), point-to-point communication (# messages, bytes sent and received)  I/O (# operations, wait time, inclusive wait time, total bytes)  All metrics recorded as “time histograms” (fixed-size data structure) Profiled entities  Functions only (but includes functions linked to in existing libraries)

8 Paradyn Visualizations  Time histograms  Tables  Barcharts  “Terrains” (3-D histograms)

9 Paradyn – time histograms

10 Paradyn – terrain plot (histogram across multiple hosts)

11 Paradyn – table (current metric values)

12 Paradyn – bar chart (current or average metric values)

13 MPE/Jumpshot Metrics collected  MPI message send time, receive time, size, message sender/recipient  User-defined event entry & exit Profiled entities  All MPI functions  Functions or regions via manual instrumentation and custom events Visualization  Jumpshot: timeline view (space-time diagram overlaid on Gantt chart), histogram

14 Jumpshot – timeline view

15 Jumpshot – histogram view

16 Dimemas/Paraver/MPITrace Metrics recorded (MPITrace)  All MPI functions  Hardware counters (2 from the following two lists, uses PAPI) Counter 1  Cycles  Issued instructions, loads, stores, store conditionals  Failed store conditionals  Decoded branches  Quadwords written back from scache(?)  Correctible scache data array errors(?)  Primary/secondary I-cache misses  Instructions mispredicted from scache way prediction table(?)  External interventions (cache coherency?)  External invalidations (cache coherency?)  Graduated instructions  Counter 2 Cycles Graduated instructions, loads, stores, store conditionals, floating point instructions TLB misses Mispredicted branches Primary/secondary data cache miss rates Data mispredictions from scache way prediction table(?) External intervention/invalidation (cache coherency?) Store/prefetch exclusive to clean/shared block

17 Dimemas/Paraver/MPITrace Profiled entities (MPITrace)  All MPI functions (message start time, message end time, message size, message recipient/sender)  User regions/functions via manual instrumentation Visualization  Timeline display (like Jumpshot) Shows Gantt chart and messages Also can overlay hardware counter information  Clicking on timeline brings up a text listing of events near where you clicked  1D/2D analysis modules

18 Paraver – timeline (standard)

19 Paraver – timeline (HW counter)

20 Paraver – text module

21 Paraver – 1D analysis

22 Paraver – 2D analysis

23 mpiP Metrics collected  Start time, end time, message size for each MPI call Profiled entities  MPI function calls + PMPI wrapper Visualization  Text-based output, with graphical browser that displays statistics in-line with source  Displayed information: Overall time (%) for each MPI node Top 20 callsites for time (MPI%, App%, variance) Top 20 callsites for message size (MPI%, App%, variance) Min/max/average/MPI%/App% time spent at each call site Min/max/average/sum of message sizes at each call site  App time = wall clock time between MPI_Init and MPI_Finalize  MPI time = all time consumed by MPI functions  App% = % of metric in relation to overall app time  MPI% = % of metric in relation to overall MPI time

24 mpiP – graphical view

25 Dynaprof Metrics collected  Wall clock time or PAPI metric for each profiled entity  Collects inclusive, exclusive, and 1-level call tree % information Profiled entities  Functions (dynamic instrumentation) Visualizations  Simple text-based  Simple GUI (shows same info as text-based)

26 Dynaprof – output dynaprof]$ wallclockrpt lu- 1.wallclock Exclusive Profile. Name Percent Total Calls TOTAL e+11 1 unknown e+11 1 main 3.837e Inclusive Profile. Name Percent Total SubCalls TOTAL e+11 0 main e Level Inclusive Call Tree. Parent/-Child Percent Total Calls TOTAL e+11 1 main e f_setarg e e f_setsig e e f_init e e atexit e e MAIN__

27 KOJAK Metrics collected  MPI: message start time, receive time, size, message sender/recipient  Manual instrumentation: start and stop times  1 PAPI metric / run (only FLOPS and L1 data misses visualized) Profiled entities  MPI calls (MPI wrapper library)  Function calls (automatic instrumentation, only available on a few platforms)  Regions and function calls via manual instrumentation Visualizations  Can export traces to Vampir trace format (see ICT)  Shows profile and analyzed data via CUBE (described on next few slides)

28 CUBE overview: simple description Uses a 3-pane approach to display information  Metric pane  Module/calltree pane Right-clicking brings up source code location  Location pane (system tree) Each item is displayed along with a color to indicate severity of condition  Severity can be expressed 4 ways Absolute (time) Percentage Relative percentage (changes module & location pane) Comparative percentage (differences between executions) Despite documentation, interface is actually quite intuitive

29 CUBE example: CAMEL After opening the.cube file (default metric shown = absolute time take in seconds)

30 CUBE example: CAMEL After expanding all 3 root nodes; color shown indicates metric “severity” (amount of time)

31 CUBE example: CAMEL Selecting “Execution” shows execution time, broken down into part of code & machine

32 CUBE example: CAMEL Selecting mainloop adjusts system tree to only show time spent in mainloop per each processor

33 CUBE example: CAMEL Expanded nodes show exclusive metric (only time spent by node)

34 CUBE example: CAMEL Collapsed nodes show inclusive metric (time spent by node and all children nodes)

35 CUBE example: CAMEL Metric pane also shows detected bottlenecks; here, shows “Late Sender” in MPI_Recv within main spread across all nodes

36 Intel Cluster Tools (ICT) Metrics collected  MPI functions: start time, end time, message size, message sender/recipient  User-defined events: counter, start & end times  Code location for source-code correlation Instrumented entities  MPI functions via wrapper library  User functions via binary instrumentation(?)  User functions & regions via manual instrumentation Visualizations  Different types: timelines, statistics & counter info  Described in next slides

37 ICT visualizations – timelines & summaries Summary Chart Display  Allows the user to see how much work is spent in MPI calls Timeline Display  Zoomable, scrollable timeline representation of program execution Fig. 1 Summary Chart Fig. 2 Timeline Display

38 ICT visualizations – histogram & counters Summary Timeline  Timeline/histogram representation showing the number of processes in each activity per time bin Counter Timeline  Value over time representation (behavior depends on counter definition in trace) Fig. 3 Summary TImeline Fig 4. Counter Timeline

39 ICT visualizations – message stats & process profiles Message Statistics Display  Message data to/from each process (count,length, rate, duration) Process Profile Display  Per process data regarding activities Fig. 5 Message Statistics Fig. 6 Process Profile Display

40 ICT visualizations – general stats & call tree Statistics Display  Various statistics regarding activities in histogram, table, or text format Call Tree Display Fig. 7 Statistics Display Fig. 8 Call Tree Display

41 ICT visualizations – source & activity chart Source View  Source code correlation with events in Timeline Activity Chart  Per Process histograms of Application and MPI activity Fig 9. Source View Fig. 10 Activity Chart

42 ICT visualizations – process timeline & activity chart Process Timeline  Activity timeline and counter timeline for a single process Process Activity Chart  Same type of informartion as Global Summary Chart Process Call Tree  Same type of information as Global Call Tree Figure 11. Process Timeline Figure 12. Process Activity Chart & Call Tree

43 Pablo Metrics collected  Time inclusive/exclusive of a function  Hardware counters via PAPI  Summary metrics computed from timing info Min/max/avg/stdev/count Profiled entities  Functions, function calls, and outer loops  All selected via GUI Visualizations  Displays derived summary metrics color-coded and inline with source code  Shown on next slide

44 SvPablo

45 MPICL/Paragraph Metrics collected  MPI functions: start time, end time, message size, message sender/recipient  Manual instrumentation: start time, end time, “work” done (up to user to pass this in) Profiled entities  MPI function calls via PMPI interface  User functions/regions via manual instrumentation Visualizations  Many, separated into 4 categories: utilization, communication, task, “other”  Described in following slides

46 ParaGraph visualizations Utilization visualizations  Display rough estimate of processor utilization  Utilization broken down into 3 states: Idle – When program is blocked waiting for a communication operation (or it has stopped execution) Overhead – When a program is performing communication but is not blocked (time spent within MPI library) Busy – if execution part of program other than communication  “Busy” doesn’t necessarily mean useful work is being done since it assumes (not communication) := busy Communication visualizations  Display different aspects of communication  Frequency, volume, overall pattern, etc.  “Distance” computed by setting topology in options menu Task visualizations  Display information about when processors start & stop tasks  Requires manually instrumented code to identify when processors start/stop tasks Other visualizations  Miscellaneous things

47 Utilization visualizations – utilization count Displays # of processors in each state at a given moment in time Busy shown on bottom, overhead in middle, idle on top

48 Utilization visualizations – Gantt chart Displays utilization state of each processor as a function of time

49 Utilization visualizations – Kiviat diagram Shows our friend, the Kiviat diagram Each spoke is a single processor Dark green shows moving average, light green shows current high watermark  Timing parameters for each can be adjusted Metric shown can be “busy” or “busy + overhead”

50 Utilization visualizations – streak Shows “streak” of state  Similar to winning/losing streaks of baseball teams  Win = overhead or busy  Loss = idle Not sure how useful this is

51 Utilization visualizations – utilization summary Shows percentage of time spent in each utilization state up to current time

52 Utilization visualizations – utilization meter Shows percentage of processors in each utilization state at current time

53 Utilization visualizations – concurrency profile Shows histograms of # processors in a particular utilization state Ex: Diagram shows  Only 1 processor was busy ~5% of the time  All 8 processors were busy ~90% of the time

54 Communication visualizations – color code Color code controls colors used on most communication visualizations Can have color indicate message sizes, message distance, or message tag  Distance computed by topology set in options menu

55 Communication visualizations – communication traffic Shows overall traffic at a given time  Bandwidth used, or  Number of messages in flight Can show single node or aggregate of all nodes

56 Communication visualizations – spacetime diagram Shows standard space-time diagram for communication  Messages sent from node to node at which times

57 Communication visualizations – message queues Shows data about message queue lengths  Incoming/outgoing  Number of bytes queued/number of messages queued Colors mean different things  Dark color shows current moving average  Light color shows high watermark

58 Communication visualizations – communication matrix Shows which processors sent data to which other processors

59 Communication visualizations – communication meter Show percentage of communication used at the current time Message count or bandwidth 100% = max # of messages / max bandwidth used by the application at a specific time

60 Communication visualizations – animation Animates messages as they occur in trace file Can overlay messages over topology Available topologies  Mesh  Ring  Hypercube  User-specified Can layout each node as you want Can store to a file and load later on

61 Communication visualizations – node data Shows detailed communication data Can display  Metrics Which node Message tag Message distance Message length  For a single node, or aggregate for all nodes

62 Task visualizations – task count Shows number of processors that are executing a task at the current time At end of run, changes to show summary of all tasks

63 Task visualizations – task Gantt Shows Gantt chart of which task each processor was working on at a given time

64 Task visualizations – task speed Similar to Gantt chart, but displays “speed” of each task Must record work done by task in instrumentation call (not done for example shown above)

65 Task visualizations – task status Shows which tasks have started and finished at the current time

66 Task visualizations – task summary Shows % time spent on each task Also shows any overlap between tasks

67 Task visualizations – task surface Shows time spent on each task by each processor Useful for seeing load imbalance on a task-by-task basis

68 Task visualizations – task work Displays work done by each processor Shows rate and volume of work being done Example doesn’t show anything because no work amounts recorded in trace being visualized

69 Other visualizations – clock, coordinates Clock  Shows current time Coordinate information  Shows coordinates when you click on any visualization

70 Other visualizations – critical path Highlights critical path in space-time diagram in red  Longest serial path shown in red  Depends on point-to-point communication (collective can screw it up)

71 Other visualizations – phase portrait Shows relationship between processor utilization and communication usage

72 Other visualizations – statistics Gives overall statistics for run Data  % busy, overhead, idle time  Total count and bandwidth of messages  Max, min, average Message size Distance Transit time Shows max of 16 processors at a time

73 Other visualizations – processor status Shows  Processor status  Which task each processor is executing  Communication (sends & receives) Each processor is a square in the grid (8- processor example shown)

74 Other visualizations – trace events Shows text output of all trace file events