On Tue, May 18, 2021 at 11:48:34AM +0800, wangyanan (Y) wrote: > Hi Salil, > > On 2021/5/17 23:17, Salil Mehta wrote: > > > 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? > The smp_clusters is added in VirtMachineState and nowhere else because > it's currently only used for ARM. But I think maybe I should also move it to > CpuTopology structure like [1] is doing to move dies to CpuTopology.
Yes, please do that. Thanks, drew > > Move clusters to CpuTopology won't affect other architectures that don't > support it yet, and will also make it easy if they want to in the future. > > [1] From Paolo: > https://patchwork.kernel.org/project/qemu-devel/patch/20210513162901.1310239-10-pbonz...@redhat.com/ > > Thanks, > Yanan > > Salil. > > > > > ms->smp.cores = cores; > > > ms->smp.threads = threads; > > > } > > . >
