On Fri, Aug 12, 2022 at 12:04:18PM +0200, Michal Privoznik wrote:
Ideally, we would just pick the best default and users wouldn't have to intervene at all. But in some cases it may be handy to not bother with SCHED_CORE at all or place helper processes into the same group as QEMU. Introduce a knob in qemu.conf to allow users control this behaviour.
Signed-off-by: Michal Privoznik <mprivozn@redhat.com> --- src/qemu/libvirtd_qemu.aug | 1 + src/qemu/qemu.conf.in | 16 +++++++++++++ src/qemu/qemu_conf.c | 38 ++++++++++++++++++++++++++++++ src/qemu/qemu_conf.h | 13 ++++++++++ src/qemu/test_libvirtd_qemu.aug.in | 1 + 5 files changed, 69 insertions(+)
diff --git a/src/qemu/libvirtd_qemu.aug b/src/qemu/libvirtd_qemu.aug index 0f18775121..ed097ea3d9 100644 --- a/src/qemu/libvirtd_qemu.aug +++ b/src/qemu/libvirtd_qemu.aug @@ -110,6 +110,7 @@ module Libvirtd_qemu = | bool_entry "dump_guest_core" | str_entry "stdio_handler" | int_entry "max_threads_per_process" + | str_entry "sched_core"
let device_entry = bool_entry "mac_filter" | bool_entry "relaxed_acs_check" diff --git a/src/qemu/qemu.conf.in b/src/qemu/qemu.conf.in index 04b7740136..adcaccfdf1 100644 --- a/src/qemu/qemu.conf.in +++ b/src/qemu/qemu.conf.in @@ -952,3 +952,19 @@ # DO NOT use in production. # #deprecation_behavior = "none" + +# If this is set then QEMU and its threads will run in a separate scheduling +# group meaning no other process will share Hyper Threads of a single core with +# QEMU. Each QEMU has its own group. +# +# Possible options are: +# "none" - (default) nor QEMU nor any of its helper processes are placed into +# separate scheduling group
'neither QEMU or any'
+# "vcpus" - only QEMU vCPU threads are placed into a separate scheduling group, +# emulator threads and helper processes remain outside of the group +# "emulator" - only QEMU and its threads (emulator + vCPUs) are placed into +# separate scheduling group, helper proccesses remain outside of +# the group +# "full" - both QEMU and its helper processes are placed into separate +# scheduling group +#sched_core = "none"
With regards, Daniel -- |: https://berrange.com -o- https://www.flickr.com/photos/dberrange :| |: https://libvirt.org -o- https://fstop138.berrange.com :| |: https://entangle-photo.org -o- https://www.instagram.com/dberrange :|