aboutsummaryrefslogtreecommitdiff
path: root/qemu-options.hx
diff options
context:
space:
mode:
authorYanan Wang <wangyanan55@huawei.com>2021-09-29 10:58:09 +0800
committerPaolo Bonzini <pbonzini@redhat.com>2021-10-01 15:28:16 +0200
commit4a0af2930a4e4f64ce551152fdb4b9e7be106408 (patch)
tree68e17e724e2e0f4516e96767ed7d93cec8a1daf8 /qemu-options.hx
parentbbb0c0ec6da8a739b02fbff941b44afc5513d6e4 (diff)
machine: Prefer cores over sockets in smp parsing since 6.2
In the real SMP hardware topology world, it's much more likely that we have high cores-per-socket counts and few sockets totally. While the current preference of sockets over cores in smp parsing results in a virtual cpu topology with low cores-per-sockets counts and a large number of sockets, which is just contrary to the real world. Given that it is better to make the virtual cpu topology be more reflective of the real world and also for the sake of compatibility, we start to prefer cores over sockets over threads in smp parsing since machine type 6.2 for different arches. In this patch, a boolean "smp_prefer_sockets" is added, and we only enable the old preference on older machines and enable the new one since type 6.2 for all arches by using the machine compat mechanism. Suggested-by: Daniel P. Berrange <berrange@redhat.com> Signed-off-by: Yanan Wang <wangyanan55@huawei.com> Acked-by: David Gibson <david@gibson.dropbear.id.au> Acked-by: Cornelia Huck <cohuck@redhat.com> Reviewed-by: Andrew Jones <drjones@redhat.com> Reviewed-by: Pankaj Gupta <pankaj.gupta@ionos.com> Reviewed-by: Daniel P. Berrangé <berrange@redhat.com> Message-Id: <20210929025816.21076-10-wangyanan55@huawei.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'qemu-options.hx')
-rw-r--r--qemu-options.hx3
1 files changed, 2 insertions, 1 deletions
diff --git a/qemu-options.hx b/qemu-options.hx
index 2eac830fdb..8ef178180d 100644
--- a/qemu-options.hx
+++ b/qemu-options.hx
@@ -244,7 +244,8 @@ SRST
Historically preference was given to the coarsest topology parameters
when computing missing values (ie sockets preferred over cores, which
were preferred over threads), however, this behaviour is considered
- liable to change.
+ liable to change. Prior to 6.2 the preference was sockets over cores
+ over threads. Since 6.2 the preference is cores over sockets over threads.
ERST
DEF("numa", HAS_ARG, QEMU_OPTION_numa,