# Overview
-Credit (also known as Credit1) is the default virtual CPU (vCPU) scheduler
+Credit (also known as Credit1) is the old virtual CPU (vCPU) scheduler
of the Xen hypervisor.
It is a general purpose, weighted fair-share scheduler.
# User details
-Xen supports multiple schedulers. As said, Credit is the default, so it
-is used automatically, unless the `sched=$SCHED` (with `$SCHED` different
-than `credit`) parameter is passed to Xen via the bootloader.
+Xen supports multiple schedulers. Credit is no longer the default. In
+order to use it as the Xen scheduler the following parameter should be
+passed to the hypervisor at boot:
+
+ `sched=credit`
Once the system is live, for creating a cpupool with Credit as its
scheduler, either compile a cpupool configuration file, as described
Date Revision Version Notes
---------- -------- -------- -------------------------------------------
2016-10-14 1 Xen 4.8 Document written
+2019-02-7 3 Xen 4.12 No longer default scheduler
---------- -------- -------- -------------------------------------------
# Overview
-Credit2 is one of the virtual CPU (vCPU) scheduler available in the
+Credit2 is the default virtual CPU (vCPU) scheduler available in the
Xen hypervisor.
Credit2 was designed as a general purpose scheduler, with particular
focus on improving handling of mixed workloads, scalability and
-support for low latency applications inside VMs, with respect to
-Credit1.
+support for low latency applications inside VMs.
# User details
-Credit2 is not in use by default. In order to use it as the Xen
-scheduler the following parameter should be passed to the hypervisor
-at boot:
-
- `sched=credit2`
+Xen supports multiple schedulers. As said, Credit2 is the default, so
+it is used automatically, unless the `sched=$SCHED` (with `$SCHED`
+different than `credit2`) parameter is passed to Xen via the
+bootloader.
Other parameters are available for tuning the behavior of Credit2
(see `docs/misc/xen-command-line.markdown` for a complete list and
---------- -------- -------- -------------------------------------------
2016-10-14 1 Xen 4.8 Document written
2017-11-6 2 Xen 4.10 Soft-affinity and caps implemented
+2019-02-7 3 Xen 4.12 Made the default scheduler
---------- -------- -------- -------------------------------------------