Overview of DynTG - PowerPoint PPT Presentation
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Overview of DynTG
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A release should be available 'in the next few weeks' as of 5/26/2005 according to developers ... Architecture handles both post-mortem and runtime analysis ... – PowerPoint PPT presentation
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Title: Overview of DynTG
1
Overview of DynTG
- Adam Leko
- UPC Group
- HCS Research Laboratory
- University of Florida
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Basic Information
- Name DynTG
- Developer Center for Applied Scientific
Computing, Lawrence Livermore National Laboratory - Current Version
- (Unreleased)
- Website
- http//www.llnl.gov/CASC/tool_gear/
- Contact
- Martin Schulz (schulzm_at_llnl.gov)
- John May (johnmay_at_llnl.gov)
- John Gyllenhaal (gyllen_at_llnl.gov)
3
Overview of DynTG
- Not yet publicly available yet
- A release should be available in the next few
weeks as of 5/26/2005 according to developers - Still nothing available
- Information in this overview based on 1
- DynTG brings together two existing tools DPCL
and Tool Gear - Lets the user instrument their program by viewing
source code and choosing instrumentation points
at runtime - Uses Tool Gear to provide source browser and
metric display to user - Uses DPCL to perform dynamic instrumentation at
runtime
4
Related Project DPCL
- DPCL Dynamic Probe Class Library 2
- Based on DynInst from Paradyn
- Meant to provide performance tool developers with
a library that handles instrumenting distributed
programs during runtime - Also has built-in security features
- Architecture of DPCL shown right
- Analysis tool uses DPCL super daemon to
establish secure connection to DPCL daemons on
each host - DPCL daemons (one per user per host) use DynInst
to perform instrumentation of running programs
and handle sending data back to the analysis tool - Currently only works on Linux and AIX platforms
5
Related Project Tool Gear
- Tool Gear Software infrastructure for
developing performance analysis and debugging
tools for large scale parallel programs 3 - Basic architecture shown below
- Tool Gear provides a database by which
- Performance tools give information to the tool
gear viewers - Viewers pass asynchronous events (such as
instrumentation requests) to a tool - Architecture handles both post-mortem and runtime
analysis - But Tool Gear is much more useful for tools that
perform online analysis (and hence DynTG) - However, only a few viewers that display metrics
inline with source code are currently available - Tool Gear is used in mpiPs mpipview (see mpiP
evaluation)
6
Related Project Tool Gear (2)
- A good description of the purpose of Tool Gear
(from 1, pg. 5)
Source code viewers are complex and difficult to
implement, yet required by a large number of
tools. The Tool Gear project was born based on
this observation and provides a versatile
framework for the development of interactive
tools. As its core it provides a scalable source
viewer, which can display both the source code
itself as well as multiple performance metrics on
a per source line basis. The performance data
itself is stored inside Tool Gear using a
database. Data can directly be added to this
database from a collector using the Tool Gear
communication library.
7
DynTG Architecture
- DynTG merges DPCL and ToolGears architectures
together - All analysis, instrumentation, and display are
performed while a program is running
8
DynTG Modules
- DynTG can load modules (shared objects) at
startup that report information back to the main
viewer - Similar to Dynaprofs loadable probe interface
(see Dynaprof review) - Each probe split into two pieces
- Probe module
- Contains the DPCL data probes that should be
inserted when the user requests a function to be
instrumented - Should contain code that sends data to collector
modules via DPCLs Ais_send routine - Collector module
- Receives data from the DPCL daemons, analyzes it,
and gives it to the Tool Gear viewer - According to paper 1, much low-level
functionality is already provided by DynTG - allows even unexperienced sic users not
familiar with DPCL or Tool Gear to develop new
probe/collector modules
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Built-In Modules
- Counter
- Counts how often a program executes a specific
location - Timer
- Keeps track of how much time is spent at a
location using the UNIX gettimeofday call - PMAPI
- Provides direct access to IBMs hardware counters
- Users specify which hardware counters they are
interested and specify priorities for each - Module maps users request to available hardware
resources
10
DynTG GUI
- User interacts with Tool Gear GUI to select what
parts of their code they want instrumented (see
right) - GUI loads modules and inserts probes as
previously discussed - It is not clear from the paper how the tool
handles starting programs
11
DynTG GUI (2)
12
DynTG Overhead
- In paper, authors found runtime overhead of DynTG
to be between 1.94 and 12.4 (1, page 6) - Used two applications from the ASC Purple
Benchmark Codes - SMG2000 (60x60x60)
- sPPM (64x64x64)
- They inserted single instrumentation action into
a central location (executed around 4000 times
per second) - Based on our own experience with DynInst,
overhead is very low for everything but very
lightweight functions - However, overhead can easily grow to several
hundred percent or more for applications with
functions that execute gt 105 times per second - Normally these types of functions should be
inlined, so not a major concern
13
References
- 1 M. Schulz, J. May, J. Gyllenhaal. DynTG A
Tool for - Interactive, Dynamic Instrumentation, ICSS
2005, - Atlanta, GA, May 22-25, 2005.
- 2 L. DeRose, T. Hoover Jr. The Dynamic Probe
Class Library An Infrastructure for Developing
Instrumentation for Performance Tools, IPDPS
2001, April 2001. - 3 Toolgear website http//www.llnl.gov/CASC/to
ol_gear/
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