From: Alex Jia <Alex Jia ajia(a)redhat.com&gt; The default flags are inconsistent on both qemuSetSchedulerParameters() and qemuGetSchedulerParameters() in libvirt, the qemuGetSchedulerParameters() always passes 'VIR_DOMAIN_AFFECT_CURRENT' flag to the qemuGetSchedulerParametersFlags(), it should be a expected behavior, but the qemuSetSchedulerParameters() always passes 'VIR_DOMAIN_AFFECT_LIVE' flag to the qemuSetSchedulerParametersFlags(), if users use default flag=0 or explicitly give a 'VIR_DOMAIN_AFFECT_CURRENT' flag to the set_scheduler_parameters() in perl-Sys-Virt, because the flag value is 0, the result is the virDomainSetSchedulerParameters() is called incorrectly. In fact, it's enough to call the qemuSetSchedulerParametersFlags() regardless of what flag is like 'virsh schedinfo' command. How to reproduce? # cat test.pl #!/usr/bin/env perl use warnings; use strict; use Sys::Virt; my $uri = "qemu:///system"; my $domname = "foo"; # change your guest name my $con = Sys::Virt->new(address => $uri, readonly => 0); my $dom = $con->get_domain_by_name($domname); my %sched_param = (Sys::Virt::Domain::SCHEDULER_CPU_SHARES=>1); $dom->set_scheduler_parameters(\%sched_param, Sys::Virt::Domain::AFFECT_CURRENT); # perl test.pl libvirt error code: 55, message: Requested operation is not valid: domain is not running Signed-off-by: Alex Jia <Alex Jia ajia(a)redhat.com&gt; --- Virt.xs | 10 +++------- 1 files changed, 3 insertions(+), 7 deletions(-) diff --git a/Virt.xs b/Virt.xs index 2b8d74c..fa58cc6 100644 --- a/Virt.xs +++ b/Virt.xs @@ -2833,13 +2833,9 @@ set_scheduler_parameters(dom, newparams, flags=0) } } vir_typed_param_from_hv(newparams, params, nparams); - if (flags) { - if (virDomainSetSchedulerParametersFlags(dom, params, nparams, flags) < 0) - _croak_error(); - } else { - if (virDomainSetSchedulerParameters(dom, params, nparams) < 0) - _croak_error(); - } + + if (virDomainSetSchedulerParametersFlags(dom, params, nparams, flags) < 0) + _croak_error(); Safefree(params); -- 1.7.1