> From: Qemu-devel > [mailto:qemu-devel-bounces+salil.mehta=huawei....@nongnu.org] On Behalf Of > Yanan Wang > Sent: Sunday, May 16, 2021 11:32 AM > To: Peter Maydell <peter.mayd...@linaro.org>; Paolo Bonzini > <pbonz...@redhat.com>; Andrew Jones <drjo...@redhat.com>; Michael S . Tsirkin > <m...@redhat.com>; Igor Mammedov <imamm...@redhat.com>; Shannon Zhao > <shannon.zha...@gmail.com>; qemu-devel@nongnu.org; qemu-...@nongnu.org > Cc: Song Bao Hua (Barry Song) <song.bao....@hisilicon.com>; Philippe > Mathieu-Daudé <phi...@redhat.com>; wangyanan (Y) <wangyana...@huawei.com>; > Zengtao (B) <prime.z...@hisilicon.com>; Wanghaibin (D) > <wanghaibin.w...@huawei.com>; yuzenghui <yuzeng...@huawei.com>; yangyicong > <yangyic...@huawei.com>; zhukeqian <zhukeqi...@huawei.com> > Subject: [RFC PATCH v3 4/4] hw/arm/virt: Parse -smp cluster parameter in > virt_smp_parse > > There is a separate function virt_smp_parse() in hw/virt/arm.c used > to parse cpu topology for the ARM machines. So add parsing of -smp > cluster parameter in it, then total number of logical cpus will be > calculated like: max_cpus = sockets * clusters * cores * threads. > > Note, we will assume multi-cluster in one socket is not supported > and default the value of clusters to 1, if it's not explicitly > specified in -smp cmdline. > > Signed-off-by: Yanan Wang <wangyana...@huawei.com> > --- > hw/arm/virt.c | 32 ++++++++++++++++++-------------- > 1 file changed, 18 insertions(+), 14 deletions(-) > > diff --git a/hw/arm/virt.c b/hw/arm/virt.c > index 7de822e491..678d5ef36c 100644 > --- a/hw/arm/virt.c > +++ b/hw/arm/virt.c > @@ -2642,8 +2642,8 @@ static int virt_kvm_type(MachineState *ms, const char > *type_str) > * with the -smp cmdlines when parsing them. > * > * We require that at least one of cpus or maxcpus must be provided. > - * Threads will default to 1 if not provided. Sockets and cores must > - * be either both provided or both not. > + * Clusters and threads will default to 1 if they are not provided. > + * Sockets and cores must be either both provided or both not. > * > * Note, if neither sockets nor cores are specified, we will calculate > * all the missing values just like smp_parse() does, but will disable > @@ -2652,15 +2652,18 @@ static int virt_kvm_type(MachineState *ms, const char > *type_str) > static void virt_smp_parse(MachineState *ms, QemuOpts *opts) > { > VirtMachineClass *vmc = VIRT_MACHINE_GET_CLASS(ms); > + VirtMachineState *vms = VIRT_MACHINE(ms); > > if (opts) { > unsigned cpus = qemu_opt_get_number(opts, "cpus", 0); > unsigned maxcpus = qemu_opt_get_number(opts, "maxcpus", 0); > unsigned sockets = qemu_opt_get_number(opts, "sockets", 0); > + unsigned clusters = qemu_opt_get_number(opts, "clusters", 0); > unsigned cores = qemu_opt_get_number(opts, "cores", 0); > unsigned threads = qemu_opt_get_number(opts, "threads", 0); > > - /* Default threads to 1 if not provided */ > + /* Default clusters and threads to 1 if not provided */ > + clusters = clusters > 0 ? clusters : 1; > threads = threads > 0 ? threads : 1; > > if (cpus == 0 && maxcpus == 0) { > @@ -2676,13 +2679,13 @@ static void virt_smp_parse(MachineState *ms, QemuOpts > *opts) > cores = 1; > if (cpus == 0) { > sockets = 1; > - cpus = sockets * cores * threads; > + cpus = sockets * clusters * cores * threads; > } else { > maxcpus = maxcpus > 0 ? maxcpus : cpus; > - sockets = maxcpus / (cores * threads); > + sockets = maxcpus / (clusters * cores * threads); > } > } else if (sockets > 0 && cores > 0) { > - cpus = cpus > 0 ? cpus : sockets * cores * threads; > + cpus = cpus > 0 ? cpus : sockets * clusters * cores * threads; > maxcpus = maxcpus > 0 ? maxcpus : cpus; > } else { > error_report("sockets and cores must be both provided " > @@ -2695,25 +2698,26 @@ static void virt_smp_parse(MachineState *ms, QemuOpts > *opts) > exit(1); > } > > - if (sockets * cores * threads < cpus) { > + if (sockets * clusters * cores * threads < cpus) { > error_report("cpu topology: " > - "sockets (%u) * cores (%u) * threads (%u) < " > - "smp_cpus (%u)", > - sockets, cores, threads, cpus); > + "sockets (%u) * clusters (%u) * cores (%u) * " > + "threads (%u) < smp_cpus (%u)", > + sockets, clusters, cores, threads, cpus); > exit(1); > } > > - if (sockets * cores * threads != maxcpus) { > + if (sockets * clusters * cores * threads != maxcpus) { > error_report("cpu topology: " > - "sockets (%u) * cores (%u) * threads (%u) " > - "!= maxcpus (%u)", > - sockets, cores, threads, maxcpus); > + "sockets (%u) * clusters (%u) * cores (%u) * " > + "threads (%u) != maxcpus (%u)", > + sockets, clusters, cores, threads, maxcpus); > exit(1); > } > > ms->smp.cpus = cpus; > ms->smp.max_cpus = maxcpus; > ms->smp.sockets = sockets; > + vms->smp_clusters = clusters;
This variable naming *smp_clusters* looks out-of-sorts. I thought a similar variable *smp_cpus* was destined to be removed for the reason given in below link - a patch by Andrew Jones? Link: https://lists.gnu.org/archive/html/qemu-arm/2020-12/msg00418.html Am I missing anything here? Salil. > ms->smp.cores = cores; > ms->smp.threads = threads; > }