Re: [libvirt] [PATCH 1/3] conf: Add support for virtio-net.rx_queue_size

https://bugzilla.redhat.com/show_bug.cgi?id=1366989 Qemu grew yet another virtio-net tunable [1]. It basically allows

users to set the size of RX virtio ring. But because virtio-net uses two separate ring buffers to pass data from/to guest they named it explicitly rx_queue_size. We should expose it in our XML too. 1: http://lists.nongnu.org/archive/html/qemu-devel/2016-08/msg02029.html

Signed-off-by: Michal Privoznik <mprivozn(a)redhat.com&gt; --- docs/formatdomain.html.in | 7 +++++- docs/schemas/domaincommon.rng | 5 ++++ src/conf/domain_conf.c | 16 ++++++++++++ src/conf/domain_conf.h | 1 + src/qemu/qemu_domain.c | 7 ++++++ .../qemuxml2argv-net-virtio-rxqueuesize.xml | 29 ++++++++++++++++++++++ 6 files changed, 64 insertions(+), 1 deletion(-) create mode 100644 tests/qemuxml2argvdata/qemuxml2argv-net-virtio-rxqueuesize.xml diff --git a/docs/formatdomain.html.in b/docs/formatdomain.html.in index bfbb0f2..6642dc8 100644 --- a/docs/formatdomain.html.in +++ b/docs/formatdomain.html.in @@ -4604,7 +4604,7 @@ qemu-kvm -net nic,model=? /dev/null &lt;source network='default'/&gt; &lt;target dev='vnet1'/&gt; &lt;model type='virtio'/&gt; - <b>&lt;driver name='vhost' txmode='iothread' ioeventfd='on' event_idx='off' queues='5'&gt; + <b>&lt;driver name='vhost' txmode='iothread' ioeventfd='on' event_idx='off' queues='5' rxqueuesize='128'&gt; &lt;host csum='off' gso='off' tso4='off' tso6='off' ecn='off' ufo='off' mrg_rxbuf='off'/&gt; &lt;guest csum='off' tso4='off' tso6='off' ecn='off' ufo='off'/&gt; &lt;/driver&gt; @@ -4720,6 +4720,11 @@ qemu-kvm -net nic,model=? /dev/null <span class="since">virtio-net since 1.0.6 (QEMU and KVM only)</span> <span class="since">vhost-user since 1.2.17 (QEMU and KVM only)</span> </dd> + <dt><code>rxqueuesize</code></dt> + <dd> + The optional <code>rxqueuesize</code> attribute controls + the size of virtio ring for each queue as described above.

+ </dd> </dl> <p> Offloading options for the host and guest can be configured using diff --git a/docs/schemas/domaincommon.rng b/docs/schemas/domaincommon.rng index 052f28c..4b89a86 100644 --- a/docs/schemas/domaincommon.rng +++ b/docs/schemas/domaincommon.rng @@ -2529,6 +2529,11 @@ </attribute> </optional> <optional> + <attribute name='rxqueuesize'> + <ref name='positiveInteger'/> + </attribute> + </optional> + <optional> <attribute name="txmode"> <choice> <value>iothread</value> diff --git a/src/conf/domain_conf.c b/src/conf/domain_conf.c index 14d4f7d..08cde19 100644 --- a/src/conf/domain_conf.c +++ b/src/conf/domain_conf.c @@ -8911,6 +8911,7 @@ virDomainNetDefParseXML(virDomainXMLOptionPtr xmlopt, char *ioeventfd = NULL; char *event_idx = NULL; char *queues = NULL; + char *rxqueuesize = NULL; char *str = NULL; char *filter = NULL; char *internal = NULL; @@ -9083,6 +9084,7 @@ virDomainNetDefParseXML(virDomainXMLOptionPtr xmlopt, ioeventfd = virXMLPropString(cur, "ioeventfd"); event_idx = virXMLPropString(cur, "event_idx"); queues = virXMLPropString(cur, "queues"); + rxqueuesize = virXMLPropString(cur, "rxqueuesize"); } else if (xmlStrEqual(cur->name, BAD_CAST "filterref")) { if (filter) { virReportError(VIR_ERR_XML_ERROR, "%s", @@ -9466,6 +9468,17 @@ virDomainNetDefParseXML(virDomainXMLOptionPtr xmlopt, if (q > 1) def->driver.virtio.queues = q; } + if (rxqueuesize) { + unsigned int q; + if (virStrToLong_uip(rxqueuesize, NULL, 10, &q) < 0) { + virReportError(VIR_ERR_XML_DETAIL, + _("'rxqueuesize' attribute must be positive number: %s"), + rxqueuesize); + goto error; + } + if (q > 1) + def->driver.virtio.rxqueuesize = q; + } if ((str = virXPathString("string(./driver/host/@csum)", ctxt))) { if ((val = virTristateSwitchTypeFromString(str)) <= 0) { virReportError(VIR_ERR_CONFIG_UNSUPPORTED, @@ -9646,6 +9659,7 @@ virDomainNetDefParseXML(virDomainXMLOptionPtr xmlopt, VIR_FREE(ioeventfd); VIR_FREE(event_idx); VIR_FREE(queues); + VIR_FREE(rxqueuesize); VIR_FREE(str); VIR_FREE(filter); VIR_FREE(type); @@ -20768,6 +20782,8 @@ virDomainVirtioNetDriverFormat(char **outstr, } if (def->driver.virtio.queues) virBufferAsprintf(&buf, "queues='%u' ", def->driver.virtio.queues); + if (def->driver.virtio.rxqueuesize) + virBufferAsprintf(&buf, "rxqueuesize='%u' ", def->driver.virtio.rxqueuesize); virBufferTrim(&buf, " ", -1); diff --git a/src/conf/domain_conf.h b/src/conf/domain_conf.h index 8b26724..9197d70 100644 --- a/src/conf/domain_conf.h +++ b/src/conf/domain_conf.h @@ -906,6 +906,7 @@ struct _virDomainNetDef { virTristateSwitch ioeventfd; virTristateSwitch event_idx; unsigned int queues; /* Multiqueue virtio-net */ + unsigned int rxqueuesize; /* rx_queue_size */ struct { virTristateSwitch csum; virTristateSwitch gso; diff --git a/src/qemu/qemu_domain.c b/src/qemu/qemu_domain.c index 6c0f261..ee24086 100644 --- a/src/qemu/qemu_domain.c +++ b/src/qemu/qemu_domain.c @@ -2372,6 +2372,13 @@ qemuDomainDeviceDefValidate(const virDomainDeviceDef *dev, "not supported by QEMU")); goto cleanup; } + + if (STREQ_NULLABLE(net->model, "virtio") && + net->driver.virtio.rxqueuesize & (net->driver.virtio.rxqueuesize -1)) {

+ virReportError(VIR_ERR_CONFIG_UNSUPPORTED, "%s", + _("rxqueuesize has to be a power of two"));

+ goto cleanup; + } } ret = 0; diff --git a/tests/qemuxml2argvdata/qemuxml2argv-net-virtio-rxqueuesize.xml b/tests/qemuxml2argvdata/qemuxml2argv-net-virtio-rxqueuesize.xml new file mode 100644 index 0000000..e23d3e3 --- /dev/null +++ b/tests/qemuxml2argvdata/qemuxml2argv-net-virtio-rxqueuesize.xml @@ -0,0 +1,29 @@ +<domain type='qemu'> + <name>QEMUGuest1</name> + <uuid>c7a5fdbd-edaf-9455-926a-d65c16db1809</uuid> + <memory unit='KiB'>219100</memory> + <currentMemory unit='KiB'>219100</currentMemory> + <vcpu placement='static'>1</vcpu> + <os> + <type arch='i686' machine='pc'>hvm</type> + <boot dev='hd'/> + </os> + <clock offset='utc'/> + <on_poweroff>destroy</on_poweroff> + <on_reboot>restart</on_reboot> + <on_crash>destroy</on_crash> + <devices> + <emulator>/usr/bin/qemu</emulator> + <disk type='block' device='disk'> + <source dev='/dev/HostVG/QEMUGuest1'/> + <target dev='hda' bus='ide'/> + </disk> + <controller type='usb' index='0'/> + <interface type='user'> + <mac address='00:11:22:33:44:55'/> + <model type='virtio'/> + <driver rxqueuesize='128'/> + </interface> + <memballoon model='virtio'/> + </devices> +</domain>