verilator/test_regress/t/t_trace_two_dumpfst_cc.pl
Geza Lore c52f3349d1
Initial implementation of generic multithreaded tracing (#2269)
The --trace-threads option can now be used to perform tracing on a
thread separate from the main thread when using VCD tracing (with
--trace-threads 1). For FST tracing --trace-threads can be 1 or 2, and
--trace-fst --trace-threads 1 is the same a what --trace-fst-threads
used to be (which is now deprecated).

Performance numbers on SweRV EH1 CoreMark, clang 6.0.0, Intel i7-3770 @
3.40GHz, IO to ramdisk, with numactl set to schedule threads on different
physical cores. Relative speedup:

--trace     ->  --trace --trace-threads 1      +22%
--trace-fst ->  --trace-fst --trace-threads 1  +38% (as --trace-fst-thread)
--trace-fst ->  --trace-fst --trace-threads 2  +93%

Speed relative to --trace with no threaded tracing:
--trace                                 1.00 x
--trace --trace-threads 1               0.82 x
--trace-fst                             1.79 x
--trace-fst --trace-threads 1           1.23 x
--trace-fst --trace-threads 2           0.87 x

This means FST tracing with 2 extra threads is now faster than single
threaded VCD tracing, and is on par with threaded VCD tracing. You do
pay for it in total compute though as --trace-fst --trace-threads 2 uses
about 240% CPU vs 150% for --trace-fst --trace-threads 1, and 155% for
--trace --trace threads 1. Still for interactive use it should be
helpful with large designs.
2020-04-21 23:49:07 +01:00

43 lines
1.2 KiB
Perl
Executable File

#!/usr/bin/perl
if (!$::Driver) { use FindBin; exec("$FindBin::Bin/bootstrap.pl", @ARGV, $0); die; }
# DESCRIPTION: Verilator: Verilog Test driver/expect definition
#
# Copyright 2003-2020 by Wilson Snyder. This program is free software; you
# can redistribute it and/or modify it under the terms of either the GNU
# Lesser General Public License Version 3 or the Perl Artistic License
# Version 2.0.
# SPDX-License-Identifier: LGPL-3.0-only OR Artistic-2.0
# Test tracing with two models instanced
scenarios(vlt_all => 1);
top_filename("t_trace_two_a.v");
compile(
make_main => 0,
verilator_make_gmake => 0,
top_filename => 't_trace_two_b.v',
VM_PREFIX => 'Vt_trace_two_b',
verilator_flags2 => ['--trace-fst --trace-threads 1 -DTEST_FST'],
);
compile(
make_main => 0,
top_filename => 't_trace_two_a.v',
verilator_flags2 => ['-exe', '--trace-fst --trace-threads 1',
'-DTEST_FST',
"$Self->{t_dir}/t_trace_two_cc.cpp"],
v_flags2 => ['+define+TEST_DUMP'],
);
execute(
check_finished => 1,
);
if ($Self->{vlt_all}) {
fst_identical($Self->trace_filename, $Self->{golden_filename});
}
ok(1);
1;