my $lxs = $self->{lxs};
$xj ||= $lxs->concurrency($opt); # allow: "--jobs ,$WRITER_ONLY"
my $nproc = $lxs->detect_nproc || 1; # don't memoize, schedtool(1) exists
$xj = $nproc if $xj > $nproc;
$lxs->{-wq_nr_workers} = $xj;
my $lxs = $self->{lxs};
$xj ||= $lxs->concurrency($opt); # allow: "--jobs ,$WRITER_ONLY"
my $nproc = $lxs->detect_nproc || 1; # don't memoize, schedtool(1) exists
$xj = $nproc if $xj > $nproc;
$lxs->{-wq_nr_workers} = $xj;