Re: [PATCH V2 2/4] irqtop: add max iteration support

[zhenwei pi <pizhenwei@bytedance.com>]

On 3/1/25 00:13, Joe Jin wrote:
> Add support for setting the number of iterations. This is useful in
> non-interactive mode.
> 
> Signed-off-by: Joe Jin <joe.jin@oracle.com>
> Cc: Zhenwei Pi <pizhenwei@bytedance.com>
> Cc: Sami Kerola <kerolasa@iki.fi>
> Cc: Karel Zak <kzak@redhat.com>
> ---
>   bash-completion/irqtop  |  5 +++++
>   sys-utils/irqtop.1.adoc |  3 +++
>   sys-utils/irqtop.c      | 19 +++++++++++++++++--
>   3 files changed, 25 insertions(+), 2 deletions(-)
> 
> diff --git a/bash-completion/irqtop b/bash-completion/irqtop
> index 215281ee8..d18ef99bb 100644
> --- a/bash-completion/irqtop
> +++ b/bash-completion/irqtop
> @@ -22,6 +22,10 @@ _irqtop_module()
>   			COMPREPLY=( $(compgen -W "secs" -- $cur) )
>   			return 0
>   			;;
> +		'-n'|'--iter')
> +			COMPREPLY=( $(compgen -W "the max iterations" -- $cur) )
> +			return 0
> +			;;
>   		'-s'|'--sort')
>   			COMPREPLY=( $(compgen -W "irq total delta name" -- $cur) )
>   			return 0
> @@ -47,6 +51,7 @@ _irqtop_module()
>   		--cpu-stat
>   		--cpu-list
>   		--delay
> +		--iter
>   		--sort
>   		--output
>   		--softirq
> diff --git a/sys-utils/irqtop.1.adoc b/sys-utils/irqtop.1.adoc
> index e81f4fbb6..75930f5cf 100644
> --- a/sys-utils/irqtop.1.adoc
> +++ b/sys-utils/irqtop.1.adoc
> @@ -37,6 +37,9 @@ Specify cpus in list format to show.
>   *-d*, *--delay* _seconds_::
>   Update interrupt output every _seconds_ intervals.
>   
> +*-n*, *--iter* _number_::
> +Specifies the maximum iterations before quitting.
> +
>   *-s*, *--sort* _column_::
>   Specify sort criteria by column name. See *--help* output to get column names. The sort criteria may be changes in interactive mode.
>   
> diff --git a/sys-utils/irqtop.c b/sys-utils/irqtop.c
> index 81a137be0..17c7d72cb 100644
> --- a/sys-utils/irqtop.c
> +++ b/sys-utils/irqtop.c
> @@ -83,6 +83,7 @@ struct irqtop_ctl {
>   	cpu_set_t *cpuset;
>   
>   	enum irqtop_cpustat_mode cpustat_mode;
> +	int64_t	iter;
>   	bool	batch;
>   	bool	request_exit,
>   		softirq;
> @@ -190,6 +191,12 @@ static int update_screen(struct irqtop_ctl *ctl, struct irq_output *out)
>   	if (ctl->prev_stat)
>   		free_irqstat(ctl->prev_stat);
>   	ctl->prev_stat = stat;
> +
> +	if (ctl->iter > 0) {
> +		ctl->iter--;
> +		if (ctl->iter == 0)
> +			ctl->request_exit = 1;
> +	}
>   	return 0;
>   }

If ctl->iter is initialized as int64_max, then we have codes like:

if (--ctl->iter == 0) {
     ctl->request_exit = 1;
}

>   
> @@ -295,6 +302,7 @@ static void __attribute__((__noreturn__)) usage(void)
>   	fputs(_(" -c, --cpu-stat <mode> show per-cpu stat (auto, enable, disable)\n"), stdout);
>   	fputs(_(" -C, --cpu-list <list> specify cpus in list format\n"), stdout);
>   	fputs(_(" -d, --delay <secs>   delay updates\n"), stdout);
> +	fputs(_(" -n, --iter <number>  the maximum number of iterations\n"), stdout);
>   	fputs(_(" -o, --output <list>  define which output columns to use\n"), stdout);
>   	fputs(_(" -s, --sort <column>  specify sort column\n"), stdout);
>   	fputs(_(" -S, --softirq        show softirqs instead of interrupts\n"), stdout);
> @@ -327,6 +335,7 @@ static void parse_args(	struct irqtop_ctl *ctl,
>   		{"cpu-stat", required_argument, NULL, 'c'},
>   		{"cpu-list", required_argument, NULL, 'C'},
>   		{"delay", required_argument, NULL, 'd'},
> +		{"iter", required_argument, NULL, 'n'},
>   		{"sort", required_argument, NULL, 's'},
>   		{"output", required_argument, NULL, 'o'},
>   		{"softirq", no_argument, NULL, 'S'},
> @@ -337,7 +346,7 @@ static void parse_args(	struct irqtop_ctl *ctl,
>   	};
>   	int o;
>   
> -	while ((o = getopt_long(argc, argv, "bc:C:d:o:s:St:hV", longopts, NULL)) != -1) {
> +	while ((o = getopt_long(argc, argv, "bc:C:d:n:o:s:St:hV", longopts, NULL)) != -1) {
>   		switch (o) {
>   		case 'b':
>   			ctl->batch = 1;
> @@ -377,6 +386,11 @@ static void parse_args(	struct irqtop_ctl *ctl,
>   				ctl->timer.it_value = ctl->timer.it_interval;
>   			}
>   			break;
> +		case 'n':
> +			ctl->iter = str2num_or_err(optarg, 10,
> +					_("failed to parse iter argument"),
> +					0, INT_MAX);
> +			break;
>   		case 's':
>   			set_sort_func_by_name(out, optarg);
>   			break;
> @@ -423,7 +437,8 @@ int main(int argc, char **argv)
>   	};
>   	struct irqtop_ctl ctl = {
>   		.timer.it_interval = {3, 0},
> -		.timer.it_value = {3, 0}
> +		.timer.it_value = {3, 0},
> +		.iter = -1
>   	};
>   
>   	setlocale(LC_ALL, "");