See my node Calling External Commands More Safely: IMHO on Linux IPC::Run is the best way to manage external commands while your Perl script does something else, like sending that process a signal (as others have pointed out, Ctrl-C is SIGINT):

#!/usr/bin/env perl
use warnings;
use strict;
use IPC::Run qw/start/;

print "Starting trace-cmd...\n";
my @cmd = ('sudo','trace-cmd','record',
    '-p','function','-cP',$$);  # just an example
my $h = start \@cmd, \my $stdin, \my $stdout, \my $stderr;

# wait for trace-cmd to say something before continuing
$h->pump until length $stdout || length $stderr;
#print "<<$stdout||$stderr>>\n";  # just for debugging

# This sleep is just a stand-in for something more complex
print "Waiting 2 seconds...\n";
sleep 2;

print "Sending SIGINT...\n";
$h->signal('INT');

print "Finishing...\n";
$h->finish or die "trace-cmd record returned $?";

print "Done, resetting...\n";
system('sudo','trace-cmd','reset')==0
    or die "trace-cmd reset returned $?";
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