Users can set SCHED_DEADLINE as a scheduling policy.
For example, for setting runtime = 10000000, deadline = 15000000
and period = 20000000 for vcpus 0-2:
<cputune>
...
<vcpusched vcpus="0-2" scheduler="deadline" runtime="10000000"
deadline="15000000" period="20000000"/>
...
</cputune>
Update release notes accordingly.
Signed-off-by: Sasha Algisi <sasha.algisi@xxxxxxxxxxxx>
Signed-off-by: Dario Faggioli <dfaggioli@xxxxxxxx>
---
NEWS.rst | 5 +++
docs/formatdomain.rst | 16 +++++++---
src/conf/domain_conf.c | 52 ++++++++++++++++++++++++++++---
src/conf/schemas/domaincommon.rng | 16 ++++++++++
4 files changed, 80 insertions(+), 9 deletions(-)
diff --git a/NEWS.rst b/NEWS.rst
index ef298da539..23484afdc2 100644
--- a/NEWS.rst
+++ b/NEWS.rst
@@ -17,6 +17,11 @@ v8.7.0 (unreleased)
* **New features**
+ * qemu: support for SCHED_DEADLINE scheduling
+
+ Users can now use the SCHED_DEADLINE scheduling policy for tasks
+ associated to virtual CPUs, IO Threads and Emulator processes.
+
* **Improvements**
* **Bug fixes**
diff --git a/docs/formatdomain.rst b/docs/formatdomain.rst
index 1ed969ac3e..216262b79d 100644
--- a/docs/formatdomain.rst
+++ b/docs/formatdomain.rst
@@ -910,10 +910,11 @@ CPU Tuning
support since 2.1.0`
``vcpusched``, ``iothreadsched`` and ``emulatorsched``
The optional ``vcpusched``, ``iothreadsched`` and ``emulatorsched`` elements
- specify the scheduler type (values ``batch``, ``idle``, ``fifo``, ``rr``) for
- particular vCPU, IOThread and emulator threads respectively. For ``vcpusched``
- and ``iothreadsched`` the attributes ``vcpus`` and ``iothreads`` select which
- vCPUs/IOThreads this setting applies to, leaving them out sets the default.
+ specify the scheduler type (values ``batch``, ``idle``, ``fifo``, ``rr``,
+ ``deadline`` :since:`Since 8.7.0`) for particular vCPU, IOThread and emulator
+ threads respectively. For ``vcpusched`` and ``iothreadsched`` the attributes
+ ``vcpus`` and ``iothreads`` select which vCPUs/IOThreads this setting applies
+ to, leaving them out sets the default.
The element ``emulatorsched`` does not have that attribute. Valid ``vcpus``
values start at 0 through one less than the number of vCPU's defined for the
domain. Valid ``iothreads`` values are described in the `IOThreads Allocation`_
@@ -923,6 +924,13 @@ CPU Tuning
priority must be specified as well (and is ignored for non-real-time ones).
The value range for the priority depends on the host kernel (usually 1-99).
:since:`Since 1.2.13` ``emulatorsched`` :since:`since 5.3.0`
+ For SCHED_DEADLINE (``deadline``), runtime , deadline and period must also
+ be specified (they are ignored in other schedulers). It must always be true
+ that: runtime <= deadline <= period.
+ The values are specified in nanoseconds. The valid range for the parameters
+ is [1024, 2^63-1] (but a smaller one can be put in place via sysctl). The
+ period can be set to 0, in which case, a period equal to the deadline is
+ used.
``cachetune`` :since:`Since 4.1.0`
Optional ``cachetune`` element can control allocations for CPU caches using
the resctrl on the host. Whether or not is this supported can be gathered
diff --git a/src/conf/domain_conf.c b/src/conf/domain_conf.c
index e85cc1f809..86ada8f147 100644
--- a/src/conf/domain_conf.c
+++ b/src/conf/domain_conf.c
@@ -16693,7 +16693,10 @@ virDomainLoaderDefParseXML(virDomainLoaderDef *loader,
static int
virDomainSchedulerParseCommonAttrs(xmlNodePtr node,
virProcessSchedPolicy *policy,
- int *priority)
+ int *priority,
+ uint64_t *runtime,
+ uint64_t *deadline,
+ uint64_t *period)
{
if (virXMLPropEnum(node, "scheduler", virProcessSchedPolicyTypeFromString,
VIR_XML_PROP_REQUIRED | VIR_XML_PROP_NONZERO,
@@ -16706,6 +16709,20 @@ virDomainSchedulerParseCommonAttrs(xmlNodePtr node,
return -1;
}
+ if (*policy == VIR_PROC_POLICY_DEADLINE) {
+ if (virXMLPropULongLong(node, "runtime", 10, VIR_XML_PROP_REQUIRED,
+ (unsigned long long *) runtime) < 0)
+ return -1;
+
+ if (virXMLPropULongLong(node, "deadline", 10, VIR_XML_PROP_REQUIRED,
+ (unsigned long long *) deadline) < 0)
+ return -1;
+
+ if (virXMLPropULongLong(node, "period", 10, VIR_XML_PROP_REQUIRED,
+ (unsigned long long *) period) < 0)
+ return -1;
+ }
+
return 0;
}
@@ -16720,7 +16737,10 @@ virDomainEmulatorSchedParse(xmlNodePtr node,
if (virDomainSchedulerParseCommonAttrs(node,
&sched->policy,
- &sched->priority) < 0)
+ &sched->priority,
+ &sched->runtime,
+ &sched->deadline,
+ &sched->period) < 0)
return -1;
def->cputune.emulatorsched = g_steal_pointer(&sched);
@@ -16733,7 +16753,10 @@ virDomainSchedulerParse(xmlNodePtr node,
const char *elementName,
const char *attributeName,
virProcessSchedPolicy *policy,
- int *priority)
+ int *priority,
+ uint64_t *runtime,
+ uint64_t *deadline,
+ uint64_t *period)
{
g_autoptr(virBitmap) ret = NULL;
g_autofree char *tmp = NULL;
@@ -16755,7 +16778,8 @@ virDomainSchedulerParse(xmlNodePtr node,
return NULL;
}
- if (virDomainSchedulerParseCommonAttrs(node, policy, priority) < 0)
+ if (virDomainSchedulerParseCommonAttrs(node, policy, priority,
+ runtime, deadline, period) < 0)
return NULL;
return g_steal_pointer(&ret);
@@ -16773,10 +16797,14 @@ virDomainThreadSchedParseHelper(xmlNodePtr node,
virDomainThreadSchedParam *sched = NULL;
virProcessSchedPolicy policy = 0;
int priority = 0;
+ uint64_t runtime = 0;
+ uint64_t deadline = 0;
+ uint64_t period = 0;
g_autoptr(virBitmap) map = NULL;
if (!(map = virDomainSchedulerParse(node, elementName, attributeName,
- &policy, &priority)))
+ &policy, &priority, &runtime,
+ &deadline, &period)))
return -1;
while ((next = virBitmapNextSetBit(map, next)) > -1) {
@@ -16792,6 +16820,9 @@ virDomainThreadSchedParseHelper(xmlNodePtr node,
sched->policy = policy;
sched->priority = priority;
+ sched->runtime = runtime;
+ sched->deadline = deadline;
+ sched->period = period;
}
return 0;
@@ -26029,6 +26060,17 @@ virDomainSchedulerFormat(virBuffer *buf,
sched->priority);
break;
+ case VIR_PROC_POLICY_DEADLINE:
+ virBufferAsprintf(buf, "<%ssched", name);
+ if (multiple_threads)
+ virBufferAsprintf(buf, " %ss='%zu'", name, id);
+ virBufferAsprintf(buf, " scheduler='%s' runtime='%llu' deadline='%llu' period='%llu'/>\n",
+ virProcessSchedPolicyTypeToString(sched->policy),
+ (unsigned long long) sched->runtime,
+ (unsigned long long) sched->deadline,
+ (unsigned long long) sched->period);
+ break;
+
case VIR_PROC_POLICY_NONE:
case VIR_PROC_POLICY_LAST:
break;
diff --git a/src/conf/schemas/domaincommon.rng b/src/conf/schemas/domaincommon.rng
index c4f293a4c3..86daffab8c 100644
--- a/src/conf/schemas/domaincommon.rng
+++ b/src/conf/schemas/domaincommon.rng
@@ -1168,6 +1168,22 @@
<ref name="unsignedShort"/>
</attribute>
</group>
+ <group>
+ <attribute name="scheduler">
+ <choice>
+ <value>deadline</value>
+ </choice>
+ </attribute>
+ <attribute name="runtime">
+ <ref name="unsignedLong"/>
+ </attribute>
+ <attribute name="deadline">
+ <ref name="unsignedLong"/>
+ </attribute>
+ <attribute name="period">
+ <ref name="unsignedLong"/>
+ </attribute>
+ </group>
</choice>
</define>
--
2.37.1
--
------------------------
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