verilator_gantt(1)

1VERILATOR_GANTT(1)    User Contributed Perl Documentation   VERILATOR_GANTT(1)
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NAME

6       verilator_gantt - Create Gantt chart of multi-threaded execution
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SYNOPSIS

9       Creates a visual representation to help analyze Verilator multithreaded
10       simulation performance, by showing when each macro-task starts and
11       ends, and showing when each thread is busy or idle.
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13       The generated Gantt chart has time on the X-axis. Times shown are to
14       the scale printed, i.e. a certain about of time for each character
15       width.  The Y-axis shows threads, each thread's execution is shown on
16       one line.  That line shows "[" at the position in time when it
17       executes.
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19       Following the "[" is the cpu number the task executed on, followed by
20       zero or more "-" to make the width of the characters match the scaled
21       execution time, followed by a "]".  If the scale is too small, the cpu
22       number and mtask number will not be printed.  If the scale is very
23       small, a "&" indicates multiple mtasks started at that time position.
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25       Also creates a value change dump (VCD) format dump file which may be
26       viewed in a waveform viewer (e.g. "GTKWave").  See below.
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USAGE

29         Build with --prof-threads.
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31         Run a sim with +verilator+prof+threads+window 2.
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33         This will create profile_threads.dat.
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35         Then run:
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37         verilator_gantt profile_threads.dat
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39         The report will be printed on standard output, this also generates
40         profile_threads.vcd
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42         View profile_threads.vcd in a waveform viewer.
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VCD SIGNALS

45       In waveforms there are the following signals. Most signals the
46       "decimal" format will remove the leading zeros and make the traces
47       easier to read.
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49       parallelism: The number of mtasks active at this time, for best
50       performance this will match the thread count. You may want to use an
51       "analog step" format to view this signal.
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53       cpu#_thread: For the given CPU number, the thread number executing.
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55       mtask#_cpu; For the given mtask id, the CPU it is executing on.
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57       thread#_mtask: For the given thread number, the mtask id executing.
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ARGUMENTS

60       filename
61           The filename to read data from, defaults to "profile_threads.dat".
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63       --help
64           Displays this message and program version and exits.
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66       --scale n
67           On the X-axis of the generated Gantt chart, each character
68           represents this many time units. (On x86, time units are rdtsc
69           ticks.)  Defaults to 0, which will automatically compute a
70           reasonable scale where no two mtasks need to fit into same
71           character width's worth of scaled time.
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73       --no-vcd
74       --vcd filename
75           Set output filename for vcd dump, or disable. Default is
76           verilator_gantt.vcd.
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DISTRIBUTION

79       The latest version is available from <https://verilator.org>.
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81       Copyright 2018-2021 by Wilson Snyder. This program is free software;
82       you can redistribute it and/or modify it under the terms of either the
83       GNU Lesser General Public License Version 3 or the Perl Artistic
84       License Version 2.0.
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86       SPDX-License-Identifier: LGPL-3.0-only OR Artistic-2.0
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AUTHORS

89       Wilson Snyder <wsnyder@wsnyder.org>
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