Harnessing Big Data
to Simplify Debugging
Asi Lifshitz, CTO
www.thevtool.com
May9,9,2016
2016
May
1
Agenda
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•
•
•
•
Introduction
What is Big Data, Anyway?
Simulation Log Files
Graphical Representation of a Log File
Summary
May 9, 2016
2
RTL Debugging
• Verification is one of the major bottlenecks towards
tape-out
• Debugging failing
tests is complex
and time-consuming
Source: Wilson Research & Mentor Graphics, 2014
May 9, 2016
3
Debugging Today
• Iterating between the waveforms and the simulation
log file
• Simulation log files can reach several GB
May 9, 2016
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Debugging Tomorrow
• Big Data tools will quickly and efficiently extract data
from huge log files
• Extracting and manipulating data gets simpler
• Data can be presented in a graphical way
• Shortening the debug time will
shorten the project schedule
and increase the
engineer’s productivity
May 9, 2016
5
Agenda
•
•
•
•
•
Introduction
What is Big Data, Anyway?
Simulation Log Files
Graphical Representation of a Log File
Summary
May 9, 2016
6
Big Data
• Big data is a term for data sets that are so large or
complex that traditional data processing applications
are inadequate
• The term often refers simply to the usage of
advanced methods for extracting value from data,
and seldom to a particular size of data set
May 9, 2016
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Big Data – Cont.
• For some organizations, facing few gigabytes of data
for the first time may trigger a need to reconsider
data management options
• For others, it may take tens or hundreds of terabytes
before data size becomes a significant consideration
May 9, 2016
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Database
• A database is an organized collection of data
• The data is typically organized in a way that supports
processes that require information
• A database management system (DBMS) is a
computer software application that interacts with
the user, other applications, and the database itself
to capture and analyze data
May 9, 2016
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Database for Log Files
• Database can be used to query a specific record, i.e.,
a specific message
• However, if some computation is required a
database search engine is to be used
– A concrete example which goes beyond the capabilities of
a database, is when the DV engineer would like to see all
messages from time point tp1 to time point tp2
May 9, 2016
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Database Search Engine
• A search engine allows the user to search for
information using simple keywords
May 9, 2016
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• A free and open-source database search engine,
originally written in Java
• Has been ported to Delphi, Perl, C#, C++, Python,
Ruby, and PHP
• Suitable for any application that requires full text
indexing and searching capability
• The core of its logical architecture is the idea of a
document containing fields of text
May 9, 2016
12
Agenda
•
•
•
•
•
Introduction
What is Big Data, Anyway?
Simulation Log Files
Graphical Representation of a Log File
Summary
May 9, 2016
13
Lucene for Verification
• A simulation log file is a structured textual file, and as
such it can be indexed
• Once indexed, Lucene API can be used to search for
all the ”interesting” events that are needed for
debugging a failing test
May 9, 2016
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UVM
• The Universal Verification Methodology (UVM) is a
standardized methodology for verifying integrated
circuit designs
• More than 70% of the
industry have adopted
UVM, and the numbers
will only grow with time
Source: Wilson Research & Mentor Graphics, 2014
May 9, 2016
15
UVM Messages
• UVM-based simulation contains UVM messages that
usually have the following format:
Verbosity
Filename(line)
Timepoint
Emitter
Message
May 9, 2016
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UVM Message Example
•
UVM_ERROR /project/sflash/verification/SFLASH_controller_ENV/src/sflash_controller_env_sb.sv(1863) @
4498000: uvm_test_top.env.sb [WRITE_MODE_SPI_DATA_ERR] Sent data packet contains 0x532e4000, but
expected 0x532e4cb3
• UVM ERROR is the verbosity (or severity)
• /project/sflash/verification/SFLASH_controller_ENV/src/sflash
_controller_env_sb.sv(1863) is the filename(line)
• @ 4498000 is the time point
• uvm_test_top.env.sb is the emitter of the message
• [WRITE_MODE_SPI_DATA_ERR] Sent data packet contains
0x532e4000, but expected 0x532e4cb3 is the message
May 9, 2016
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Using Lucene for UVM Messages
• Parse the log file, so that every message will be
broken to the aforementioned 5 elements and stored
as records in Lucene database
• The user can now use the efficient API of Lucene to
extract information
May 9, 2016
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Extracting UVM Records
• Being designed to handle huge records, Lucene
returns these records in a negligible time
– Receive all messages of a specific verbosity, or specific
verbosity within some time range
– Messages containing a specific string
– All messages emitted from the APB UVC writing 0X1 to
register sflash_reg.enable
May 9, 2016
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Agenda
•
•
•
•
•
Introduction
What is Big Data, Anyway?
Simulation Log Files
Graphical Representation of a Log File
Summary
May 9, 2016
20
Why Graphical Representation?
• It is extremely hard to navigate through the log file,
while seeking for the necessary information, without
being overwhelmed or miss important information
• Graphical representation of
data is more natural and is
much easier for analysis
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Graphical Representation
of a Log File
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Graphical Debugging
• The transition from debugging a textual file to a
graphical representation is intuitive
• Problems are traced much faster.
The engineer can quickly see what is wrong, when
the pattern changes, or when some unexpected
event has occurred
May 9, 2016
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Agenda
•
•
•
•
•
Introduction
What is Big Data, Anyway?
Simulation Log Files
Graphical Representation of a Log File
Summary
May 9, 2016
24
Summary
• The complexity and size of designs these days require
new techniques, as the traditional ones impose very
long debugging time
• Harnessing tools that are used for processing Big
Data can simplify and shorten the debug time of
failing tests
• We hope that this work will encourage more
researches on importing these strong capabilities to
the existing and new EDA tools
May 9, 2016
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Thank You
May 9, 2016
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