Paolo Bonzini <pbonz...@redhat.com> writes: > On 07/07/20 07:33, Markus Armbruster wrote: >> Philippe Mathieu-Daudé <phi...@redhat.com> writes: >> >>> On 7/7/20 6:45 AM, Thomas Huth wrote: >>>> On 27/05/2020 10.47, Markus Armbruster wrote: >>>>> "info qom-tree" prints children in unstable order. This is a pain >>>>> when diffing output for different versions to find change. Print it >>>>> sorted. >>>>> >>>>> Signed-off-by: Markus Armbruster <arm...@redhat.com> >>>>> --- >>>>> qom/qom-hmp-cmds.c | 24 ++++++++++++++++-------- >>>>> 1 file changed, 16 insertions(+), 8 deletions(-) >>>> >>>> Hi Markus, >>>> >>>> this patch causes a slow down of the qtests which becomes quite massive >>>> when e.g. using the ppc64 and thourough testing. When I'm running >>>> >>>> QTEST_QEMU_BINARY="ppc64-softmmu/qemu-system-ppc64" time \ >>>> ./tests/qtest/device-introspect-test -m slow | tail -n 10 >>>> >>>> the test runs for ca. 6m40s here before the patch got applied, and for >>>> mor than 20 minutes after the patch got applied! >> >> That's surprising. > > It's a bit surprising indeed, but on the other hand using > g_queue_insert_sorted results in a quadratic loop.
The surprising part is that n turns out to be large enough for n^2 to matter *that* much. > It should probably > be fixed by using g_queue_sort, or switching to g_list_prepend+g_list_sort. Yes. Additional ideas on how to make the test less wasteful elsewhere in the thread.
