diff options
| author | Greg Kurz <groug@kaod.org> | 2019-10-03 14:02:00 +0200 |
|---|---|---|
| committer | David Gibson <david@gibson.dropbear.id.au> | 2019-10-24 09:36:55 +1100 |
| commit | 29cb4187497dcc6be80c9cd2a87764be89d940f6 (patch) | |
| tree | 94b83e02725bbf7f65633dfb60f9de446a2c91c9 | |
| parent | 06d26eeb47de96c0fa0cc1d5e95124b0a809b3ac (diff) | |
| download | qemu-29cb4187497dcc6be80c9cd2a87764be89d940f6.zip qemu-29cb4187497dcc6be80c9cd2a87764be89d940f6.tar.gz qemu-29cb4187497dcc6be80c9cd2a87764be89d940f6.tar.bz2 | |
spapr: Set VSMT to smp_threads by default
Support for setting VSMT is available in KVM since linux-4.13. Most distros
that support KVM on POWER already have it. It thus seem reasonable enough
to have the default machine to set VSMT to smp_threads.
This brings contiguous VCPU ids and thus brings their upper bound down to
the machine's max_cpus. This is especially useful for XIVE KVM devices,
which may thus allocate only one VP descriptor per VCPU.
Signed-off-by: Greg Kurz <groug@kaod.org>
Message-Id: <157010411885.246126.12610015369068227139.stgit@bahia.lan>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
| -rw-r--r-- | hw/ppc/spapr.c | 7 | ||||
| -rw-r--r-- | include/hw/ppc/spapr.h | 1 |
2 files changed, 7 insertions, 1 deletions
diff --git a/hw/ppc/spapr.c b/hw/ppc/spapr.c index 4eb97d3..428b834 100644 --- a/hw/ppc/spapr.c +++ b/hw/ppc/spapr.c @@ -2496,6 +2496,7 @@ static CPUArchId *spapr_find_cpu_slot(MachineState *ms, uint32_t id, int *idx) static void spapr_set_vsmt_mode(SpaprMachineState *spapr, Error **errp) { MachineState *ms = MACHINE(spapr); + SpaprMachineClass *smc = SPAPR_MACHINE_GET_CLASS(spapr); Error *local_err = NULL; bool vsmt_user = !!spapr->vsmt; int kvm_smt = kvmppc_smt_threads(); @@ -2522,7 +2523,7 @@ static void spapr_set_vsmt_mode(SpaprMachineState *spapr, Error **errp) goto out; } /* In this case, spapr->vsmt has been set by the command line */ - } else { + } else if (!smc->smp_threads_vsmt) { /* * Default VSMT value is tricky, because we need it to be as * consistent as possible (for migration), but this requires @@ -2531,6 +2532,8 @@ static void spapr_set_vsmt_mode(SpaprMachineState *spapr, Error **errp) * overwhelmingly common case in production systems. */ spapr->vsmt = MAX(8, smp_threads); + } else { + spapr->vsmt = smp_threads; } /* KVM: If necessary, set the SMT mode: */ @@ -4438,6 +4441,7 @@ static void spapr_machine_class_init(ObjectClass *oc, void *data) smc->irq = &spapr_irq_dual; smc->dr_phb_enabled = true; smc->linux_pci_probe = true; + smc->smp_threads_vsmt = true; } static const TypeInfo spapr_machine_info = { @@ -4505,6 +4509,7 @@ static void spapr_machine_4_1_class_options(MachineClass *mc) spapr_machine_4_2_class_options(mc); smc->linux_pci_probe = false; + smc->smp_threads_vsmt = false; compat_props_add(mc->compat_props, hw_compat_4_1, hw_compat_4_1_len); compat_props_add(mc->compat_props, compat, G_N_ELEMENTS(compat)); } diff --git a/include/hw/ppc/spapr.h b/include/hw/ppc/spapr.h index cbd1a4c..2009eb6 100644 --- a/include/hw/ppc/spapr.h +++ b/include/hw/ppc/spapr.h @@ -122,6 +122,7 @@ struct SpaprMachineClass { bool broken_host_serial_model; /* present real host info to the guest */ bool pre_4_1_migration; /* don't migrate hpt-max-page-size */ bool linux_pci_probe; + bool smp_threads_vsmt; /* set VSMT to smp_threads by default */ void (*phb_placement)(SpaprMachineState *spapr, uint32_t index, uint64_t *buid, hwaddr *pio, |