diff options
author | Luiz Capitulino <lcapitulino@redhat.com> | 2018-02-16 17:08:38 +0100 |
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committer | Cornelia Huck <cohuck@redhat.com> | 2018-02-26 12:55:26 +0100 |
commit | ce74ee3dea6273a7a6aebc157f39cffd3e388097 (patch) | |
tree | ddf9a831cb283c30072532b3c4391cb1ef72ce44 /cpus.c | |
parent | 9d0306dfdfb7e7fd8d5fbe45973566d1a8ea592d (diff) | |
download | qemu-ce74ee3dea6273a7a6aebc157f39cffd3e388097.zip qemu-ce74ee3dea6273a7a6aebc157f39cffd3e388097.tar.gz qemu-ce74ee3dea6273a7a6aebc157f39cffd3e388097.tar.bz2 |
qmp: add query-cpus-fast
The query-cpus command has an extremely serious side effect:
it always interrupts all running vCPUs so that they can run
ioctl calls. This can cause a huge performance degradation for
some workloads. And most of the information retrieved by the
ioctl calls are not even used by query-cpus.
This commit introduces a replacement for query-cpus called
query-cpus-fast, which has the following features:
o Never interrupt vCPUs threads. query-cpus-fast only returns
vCPU information maintained by QEMU itself, which should be
sufficient for most management software needs
o Drop "halted" field as it can not be retrieved in a fast
way on most architectures
o Drop irrelevant fields such as "current", "pc" and "arch"
o Rename some fields for better clarification & proper naming
standard
Signed-off-by: Luiz Capitulino <lcapitulino@redhat.com>
Signed-off-by: Viktor Mihajlovski <mihajlov@linux.vnet.ibm.com>
Message-Id: <1518797321-28356-3-git-send-email-mihajlov@linux.vnet.ibm.com>
Reviewed-by: Cornelia Huck <cohuck@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Cornelia Huck <cohuck@redhat.com>
Diffstat (limited to 'cpus.c')
-rw-r--r-- | cpus.c | 38 |
1 files changed, 38 insertions, 0 deletions
@@ -2156,6 +2156,44 @@ CpuInfoList *qmp_query_cpus(Error **errp) return head; } +/* + * fast means: we NEVER interrupt vCPU threads to retrieve + * information from KVM. + */ +CpuInfoFastList *qmp_query_cpus_fast(Error **errp) +{ + MachineState *ms = MACHINE(qdev_get_machine()); + MachineClass *mc = MACHINE_GET_CLASS(ms); + CpuInfoFastList *head = NULL, *cur_item = NULL; + CPUState *cpu; + + CPU_FOREACH(cpu) { + CpuInfoFastList *info = g_malloc0(sizeof(*info)); + info->value = g_malloc0(sizeof(*info->value)); + + info->value->cpu_index = cpu->cpu_index; + info->value->qom_path = object_get_canonical_path(OBJECT(cpu)); + info->value->thread_id = cpu->thread_id; + + info->value->has_props = !!mc->cpu_index_to_instance_props; + if (info->value->has_props) { + CpuInstanceProperties *props; + props = g_malloc0(sizeof(*props)); + *props = mc->cpu_index_to_instance_props(ms, cpu->cpu_index); + info->value->props = props; + } + + if (!cur_item) { + head = cur_item = info; + } else { + cur_item->next = info; + cur_item = info; + } + } + + return head; +} + void qmp_memsave(int64_t addr, int64_t size, const char *filename, bool has_cpu, int64_t cpu_index, Error **errp) { |