Re: [Qemu-devel] [libvirt] [PATCH v7 2/2] vl:c: make sure that sockets are calculated correctly in '-smp X' case

[Eric Blake]

On 9/12/18 11:19 AM, Igor Mammedov wrote:
> commit
>    (5cdc9b76e3 vl.c: Remove dead assignment)
> removed sockets calculation when 'sockets' weren't provided on CLI
> since there wasn't any users for it back then. Exiting checks
> are neither reachable
>     } else if (sockets * cores * threads < cpus) {
> or nor triggable

s/triggable/triggerable/

>     if (sockets * cores * threads > max_cpus)
> so we weren't noticing wrong topology since then, since users
> recalculate sockets adhoc on their own.
>
> However with deprecation check it becomes noticable, for example
>    -smp 2
> will start printing warning:
>    "warning: Invalid CPU topology deprecated: sockets (1) * cores (1) * threads (1) 
> != maxcpus (2)"
> calculating sockets if they weren't specified.
>
> Fix it by returning back sockets calculation if it's omited on CLI.

s/omited/omitted/

> Signed-off-by: Igor Mammedov <address@hidden>
> Reviewed-by: Andrew Jones <address@hidden>
> ---
>   vl.c | 5 ++++-
>   1 file changed, 4 insertions(+), 1 deletion(-)
>
> diff --git a/vl.c b/vl.c
> index 7fd700e..9e56696 100644
> --- a/vl.c
> +++ b/vl.c
> @@ -1210,11 +1210,14 @@ static void smp_parse(QemuOpts *opts)
>   
>           /* compute missing values, prefer sockets over cores over threads */
>           if (cpus == 0 || sockets == 0) {
> -            sockets = sockets > 0 ? sockets : 1;
>               cores = cores > 0 ? cores : 1;
>               threads = threads > 0 ? threads : 1;
>               if (cpus == 0) {
> +                sockets = sockets > 0 ? sockets : 1;
>                   cpus = cores * threads * sockets;
> +            } else {
> +                max_cpus = qemu_opt_get_number(opts, "maxcpus", cpus);
> +                sockets = max_cpus / (cores * threads);
>               }
>           } else if (cores == 0) {
>               threads = threads > 0 ? threads : 1;

--
Eric Blake, Principal Software Engineer
Red Hat, Inc.           +1-919-301-3266
Virtualization:  qemu.org | libvirt.org