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Re: [PATCH 2/2] ppc/pnv: Use the CPU topology to compute the default num
From: |
David Gibson |
Subject: |
Re: [PATCH 2/2] ppc/pnv: Use the CPU topology to compute the default number of chips |
Date: |
Sat, 21 Dec 2019 11:39:06 +1100 |
On Fri, Dec 20, 2019 at 05:51:48PM +0100, Greg Kurz wrote:
> Multi TCG mandates the CPU topology to be dimensioned to the actual
> number of CPUs, depending on the number of chips the user asked for.
> That is, '-machine num-chips=N' should always have a '-smp' companion
> with a topology that meats the resulting number of CPUs, typically
> '-smp sockets=N'.
>
> Simplify the command line for these setups by computing the default
> number of chips based on the CPU topology, ie. no need to explicitely
> set "num-chips" anymore. This must be done at machine init because
> smp_parse() is called after instance init.
>
> Signed-off-by: Greg Kurz <address@hidden>
Is there actually any reason to retain num-chips at all? Or could we
just set the number of chips equal to the number of sockets, which
seems to make sense to me.
> ---
> hw/ppc/pnv.c | 23 ++++++++++++++++-------
> 1 file changed, 16 insertions(+), 7 deletions(-)
>
> diff --git a/hw/ppc/pnv.c b/hw/ppc/pnv.c
> index f8cf2b6d760f..9b777b7084a0 100644
> --- a/hw/ppc/pnv.c
> +++ b/hw/ppc/pnv.c
> @@ -768,6 +768,19 @@ static void pnv_init(MachineState *machine)
> exit(1);
> }
>
> + if (!pnv->num_chips) {
> + uint32_t num_chips =
> + machine->smp.max_cpus / (machine->smp.cores *
> machine->smp.threads);
> + Error *local_err = NULL;
> +
> + object_property_set_uint(OBJECT(pnv), num_chips, "num-chips",
> + &local_err);
> + if (local_err) {
> + error_report_err(local_err);
> + exit(1);
> + }
> + }
> +
> pnv->chips = g_new0(PnvChip *, pnv->num_chips);
> for (i = 0; i < pnv->num_chips; i++) {
> char chip_name[32];
> @@ -1722,6 +1735,9 @@ static void pnv_set_num_chips(Object *obj, Visitor *v,
> const char *name,
> */
> if (!is_power_of_2(num_chips) || num_chips > 4) {
> error_setg(errp, "invalid number of chips: '%d'", num_chips);
> + error_append_hint(errp,
> + "Set 'num-chips' implicitely with '-smp
> sockets=N'. "
> + "Valid values are : 1, 2 or 4.\n");
> return;
> }
>
> @@ -1735,12 +1751,6 @@ static void pnv_set_num_chips(Object *obj, Visitor *v,
> const char *name,
> pnv->num_chips = num_chips;
> }
>
> -static void pnv_machine_instance_init(Object *obj)
> -{
> - PnvMachineState *pnv = PNV_MACHINE(obj);
> - pnv->num_chips = 1;
> -}
> -
> static void pnv_machine_class_props_init(ObjectClass *oc)
> {
> object_class_property_add(oc, "num-chips", "uint32",
> @@ -1874,7 +1884,6 @@ static const TypeInfo types[] = {
> .parent = TYPE_MACHINE,
> .abstract = true,
> .instance_size = sizeof(PnvMachineState),
> - .instance_init = pnv_machine_instance_init,
> .class_init = pnv_machine_class_init,
> .class_size = sizeof(PnvMachineClass),
> .interfaces = (InterfaceInfo[]) {
>
--
David Gibson | I'll have my music baroque, and my code
david AT gibson.dropbear.id.au | minimalist, thank you. NOT _the_ _other_
| _way_ _around_!
http://www.ozlabs.org/~dgibson
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