Re: [PATCH] kvm tools: Default guest cpu count to host cpu count

[David Ahern <dsahern@gmail.com>]

On 05/18/11 13:56, Sasha Levin wrote:
> If user haven't specified cpu count for the guest, use
> the amount of online cpus on the host.
> 
> Signed-off-by: Sasha Levin <levinsasha928@gmail.com>
> ---
>  tools/kvm/kvm-run.c |    9 ++++++---
>  1 files changed, 6 insertions(+), 3 deletions(-)
> 
> diff --git a/tools/kvm/kvm-run.c b/tools/kvm/kvm-run.c
> index 63181bf..1517264 100644
> --- a/tools/kvm/kvm-run.c
> +++ b/tools/kvm/kvm-run.c
> @@ -70,7 +70,7 @@ extern int  active_console;
>  
>  bool do_debug_print = false;
>  
> -static int nrcpus = 1;
> +static int nrcpus;
>  
>  static const char * const run_usage[] = {
>  	"kvm run [<options>] [<kernel image>]",
> @@ -409,6 +409,8 @@ int kvm_cmd_run(int argc, const char **argv, const char *prefix)
>  	signal(SIGQUIT, handle_sigquit);
>  	signal(SIGUSR1, handle_sigusr1);
>  
> +	nr_online_cpus = sysconf(_SC_NPROCESSORS_ONLN);
> +
>  	while (argc != 0) {
>  		argc = parse_options(argc, argv, options, run_usage,
>  				PARSE_OPT_STOP_AT_NON_OPTION);
> @@ -439,7 +441,9 @@ int kvm_cmd_run(int argc, const char **argv, const char *prefix)
>  
>  	vmlinux_filename = find_vmlinux();
>  
> -	if (nrcpus < 1 || nrcpus > KVM_NR_CPUS)
> +	if (nrcpus == 0)
> +		nrcpus = nr_online_cpus;
> +	else if (nrcpus < 1 || nrcpus > KVM_NR_CPUS)
>  		die("Number of CPUs %d is out of [1;%d] range", nrcpus, KVM_NR_CPUS);

What prevents nr_online_cpus from being greater than KVM_NR_CPUS? Since
that latter is a #define, might want to change 'else if' to if there.

David



>  
>  	if (!ram_size)
> @@ -575,7 +579,6 @@ int kvm_cmd_run(int argc, const char **argv, const char *prefix)
>  
>  	kvm__init_ram(kvm);
>  
> -	nr_online_cpus = sysconf(_SC_NPROCESSORS_ONLN);
>  	thread_pool__init(nr_online_cpus);
>  
>  	for (i = 0; i < nrcpus; i++) {