Re: [PATCH RFC v3 02/16] schema: Add new domain elements to support multiple throttle filters

From: Chun Feng Wu <wucf(a)linux.ibm.com&gt; * Add new elements '<throttlefilters>' * <ThrottleFilters> can include multiple throttlegroup references to form filter chain in qemu * Chained throttle filters feature in qemu is described at https://github.com/qemu/qemu/blob/master/docs/throttle.txt Signed-off-by: Chun Feng Wu <wucf(a)linux.ibm.com&gt; --- docs/formatdomain.rst | 22 ++++++++++++++++++++++ src/conf/schemas/domaincommon.rng | 19 ++++++++++++++++++- 2 files changed, 40 insertions(+), 1 deletion(-) diff --git a/docs/formatdomain.rst b/docs/formatdomain.rst index b7e1f9cc83..0fa8f1267c 100644 --- a/docs/formatdomain.rst +++ b/docs/formatdomain.rst @@ -2736,6 +2736,15 @@ paravirtualized driver is specified via the ``disk`` element. <source dev='/dev/vhost-vdpa-0' /> <target dev='vdg' bus='virtio'/> </disk> + <disk type='file' device='disk'> + <driver name='qemu' type='qcow2' /> + <source file='/var/lib/libvirt/images/disk.qcow2'/> + <target dev='vdh' bus='virtio'/> + <throttlefilters> + <throttlefilter group='limit2'/> + <throttlefilter group='limit012'/> + </throttlefilters> + </disk> </devices> ... @@ -3217,6 +3226,19 @@ paravirtualized driver is specified via the ``disk`` element. :since:`since after 0.4.4`; "sata" attribute value :since:`since 0.9.7`; "removable" attribute value :since:`since 1.1.3`; "rotation_rate" attribute value :since:`since 7.3.0` +``throttlefilters`` + The optional ``throttlefilters`` element provides the ability to provide additional + per-device throttle chain :since:`Since 10.5.0` + For example, if we have four different disks and we want to limit I/O for each one + and we also want to limit combined I/O of all four disks, we can leverage + ``throttlefilters`` to achieve this goal by setting two ``throttlefilter`` for + each disk: disk's own filter(e.g. limit2) and combined filter(e.g. limit012).

+ The nodes in qemu shape a chain like libvirt-4-filter(node name of "limit012") -> + libvirt-3-filter(node name of "limit2") -> libvirt-2-format -> libvirt-1-storage. + ``throttlefilters`` and ``iotune`` should be used exclusively.

+ + ``throttlefilter`` + The optional ``throttlefilter`` element is to reference defined throttle group. ``iotune`` The optional ``iotune`` element provides the ability to provide additional per-device I/O tuning, with values that can vary for each device (contrast diff --git a/src/conf/schemas/domaincommon.rng b/src/conf/schemas/domaincommon.rng index 08c520e222..7ceb8c0be2 100644 --- a/src/conf/schemas/domaincommon.rng +++ b/src/conf/schemas/domaincommon.rng @@ -1578,7 +1578,10 @@ <ref name="encryption"/> </optional> <optional> - <ref name="diskIoTune"/> + <choice> + <ref name="throttlefilters"/> + <ref name="diskIoTune"/> + </choice> </optional> <optional> <ref name="alias"/> @@ -6671,6 +6674,20 @@ </element> </optional> </define> + <!-- + A set of throttlefilters to reference throttlegroups + --> + <define name="throttlefilters"> + <element name="throttlefilters"> + <zeroOrMore> + <element name="throttlefilter"> + <attribute name="group"> + <data type="string"/> + </attribute> + </element> + </zeroOrMore> + </element> + </define> <!-- A set of optional features: PAE, APIC, ACPI, GIC, TCG, HyperV Enlightenment, KVM features, paravirtual spinlocks and HAP support -- 2.34.1