From: Zhao Liu <zhao1.liu@xxxxxxxxx> Update the comment to make the cpu-cluster description more general for both TCG and accel cases. Signed-off-by: Zhao Liu <zhao1.liu@xxxxxxxxx> --- hw/cpu/cluster.c | 2 +- include/hw/cpu/cluster.h | 20 +++++++++++++++----- 2 files changed, 16 insertions(+), 6 deletions(-) diff --git a/hw/cpu/cluster.c b/hw/cpu/cluster.c index 340cfad9f8f1..27ab9e25a265 100644 --- a/hw/cpu/cluster.c +++ b/hw/cpu/cluster.c @@ -1,5 +1,5 @@ /* - * QEMU CPU cluster + * CPU cluster abstract device * * Copyright (c) 2018 GreenSocs SAS * diff --git a/include/hw/cpu/cluster.h b/include/hw/cpu/cluster.h index c038f05ddc9f..b3185e2f2566 100644 --- a/include/hw/cpu/cluster.h +++ b/include/hw/cpu/cluster.h @@ -1,5 +1,5 @@ /* - * QEMU CPU cluster + * CPU cluster abstract device * * Copyright (c) 2018 GreenSocs SAS * @@ -24,17 +24,27 @@ #include "qom/object.h" /* - * CPU Cluster type + * # CPU Cluster * - * A cluster is a group of CPUs which are all identical and have the same view - * of the rest of the system. It is mainly an internal QEMU representation and - * does not necessarily match with the notion of clusters on the real hardware. + * A cluster is a group of CPUs, that is, a level above the CPU (or Core). + * + * - For accel case, it's a CPU topology level concept above cores, in which + * the cores may share some resources (L2 cache or some others like L3 + * cache tags, depending on the Archs). It is used to emulate the physical + * CPU cluster/module. + * + * - For TCG, cluster is used to organize CPUs directly without core. In one + * cluster, CPUs are all identical and have the same view of the rest of the + * system. It is mainly an internal QEMU representation and may not necessarily + * match with the notion of clusters on the real hardware. * * If CPUs are not identical (for example, Cortex-A53 and Cortex-A57 CPUs in an * Arm big.LITTLE system) they should be in different clusters. If the CPUs do * not have the same view of memory (for example the main CPU and a management * controller processor) they should be in different clusters. * + * # Use case for cluster in TCG + * * A cluster is created by creating an object of TYPE_CPU_CLUSTER, and then * adding the CPUs to it as QOM child objects (e.g. using the * object_initialize_child() or object_property_add_child() functions). -- 2.34.1
