On Mon, Oct 29, 2018 at 06:34:58PM +0100, Marc Hartmayer wrote:
Introduce caching whether /dev/kvm is usable as the QEMU user:QEMU group. This reduces the overhead of the QEMU capabilities cache lookup. Before this patch there were many fork() calls used for checking whether /dev/kvm is accessible. Now we store the result whether /dev/kvm is accessible or not and we only need to re-run the virFileAccessibleAs check if the ctime of /dev/kvm has changed.
Suggested-by: Daniel P. Berrangé <berrange@redhat.com> Signed-off-by: Marc Hartmayer <mhartmay@linux.ibm.com> --- src/qemu/qemu_capabilities.c | 54 ++++++++++++++++++++++++++++++++++-- 1 file changed, 52 insertions(+), 2 deletions(-)
For benefit of those who were not at KVM Forum last week, this patch is addressing the performance problem described starting here: https://youtu.be/H3lw50IKqGo?t=1055 Regards, Daniel -- |: https://berrange.com -o- https://www.flickr.com/photos/dberrange :| |: https://libvirt.org -o- https://fstop138.berrange.com :| |: https://entangle-photo.org -o- https://www.instagram.com/dberrange :|