On Wed, May 27, 2020 at 11:12:22AM +0530, Anup Patel wrote:
> When "sockets" sub-option of "-smp" option is not specified, the
> smp_parse() function will assume one CPU per-socket and set the
> number of sockets equal to number of CPUs.
>
> This is counter-intuitive and we should allow machine emulation to
> decide default number of sockets when "sockets" sub-option is not
> specified.
I don't agree with this. Having the semantics of the -smp option
be the same across all targets/machines *is* intuitive. Changing
semantics of -smp per-machine will create a worse experiance for
people configuring QEMU as the configuration will mean different
things depending on the machine choce.
> To achieve this, we add boolean flag sockets_specified
> in struct CpuTopology which tells machine emulation whether the
> "sockets" sub-option was specified in command-line.
>
> Signed-off-by: Anup Patel <anup.pa...@wdc.com>
> ---
> hw/core/machine.c | 2 ++
> include/hw/boards.h | 2 ++
> 2 files changed, 4 insertions(+)
>
> diff --git a/hw/core/machine.c b/hw/core/machine.c
> index bb3a7b18b1..fd5ef5a4bb 100644
> --- a/hw/core/machine.c
> +++ b/hw/core/machine.c
> @@ -706,6 +706,8 @@ static void smp_parse(MachineState *ms, QemuOpts *opts)
> unsigned cores = qemu_opt_get_number(opts, "cores", 0);
> unsigned threads = qemu_opt_get_number(opts, "threads", 0);
>
> + ms->smp.sockets_specified = (sockets == 0) ? false : true;
> +
> /* compute missing values, prefer sockets over cores over threads */
> if (cpus == 0 || sockets == 0) {
> cores = cores > 0 ? cores : 1;
> diff --git a/include/hw/boards.h b/include/hw/boards.h
> index 18815d9be2..59b28ada65 100644
> --- a/include/hw/boards.h
> +++ b/include/hw/boards.h
> @@ -244,6 +244,7 @@ typedef struct DeviceMemoryState {
> * @cores: the number of cores in one package
> * @threads: the number of threads in one core
> * @sockets: the number of sockets on the machine
> + * @sockets_specified: the number of sockets were specified for the machine
> * @max_cpus: the maximum number of logical processors on the machine
> */
> typedef struct CpuTopology {
> @@ -251,6 +252,7 @@ typedef struct CpuTopology {
> unsigned int cores;
> unsigned int threads;
> unsigned int sockets;
> + bool sockets_specified;
> unsigned int max_cpus;
> } CpuTopology;
>
> --
> 2.25.1
>
>
Regards,
Daniel
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