Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18;
Date:   Wed, 27 Oct 2021 22:02:46 +0800
From:   Tao Zhou <tao.zhou@linux.dev>
To:     Daniel Bristot de Oliveira <bristot@kernel.org>
Cc:     Steven Rostedt <rostedt@goodmis.org>,
        Ingo Molnar <mingo@redhat.com>,
        Tom Zanussi <zanussi@kernel.org>,
        Masami Hiramatsu <mhiramat@kernel.org>,
        Juri Lelli <juri.lelli@redhat.com>,
        Clark Williams <williams@redhat.com>,
        John Kacur <jkacur@redhat.com>,
        Peter Zijlstra <peterz@infradead.org>,
        Thomas Gleixner <tglx@linutronix.de>,
        Sebastian Andrzej Siewior <bigeasy@linutronix.de>,
        linux-rt-users@vger.kernel.org, linux-trace-devel@vger.kernel.org,
        linux-kernel@vger.kernel.org, Tao Zhou <tao.zhou@linux.dev>
Subject: Re: [PATCH V6 08/20] rtla: Helper functions for rtla
Message-ID: <YXlcBhnqiKVxV4UX@geo.homenetwork>
References: <cover.1635284863.git.bristot@kernel.org>
 <183637700a31169e5d6d1c8a827c5365599ec806.1635284863.git.bristot@kernel.org>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <183637700a31169e5d6d1c8a827c5365599ec806.1635284863.git.bristot@kernel.org>
Precedence: bulk

Hi Daniel,

On Wed, Oct 27, 2021 at 12:06:19AM +0200, Daniel Bristot de Oliveira wrote:

> This is a set of utils and tracer helper functions. They are used by
> rtla mostly to parse config, display data and some trace operations that
> are not part of libtracefs (because they are only useful it for this
> case).
> 
> Cc: Steven Rostedt <rostedt@goodmis.org>
> Cc: Ingo Molnar <mingo@redhat.com>
> Cc: Tom Zanussi <zanussi@kernel.org>
> Cc: Masami Hiramatsu <mhiramat@kernel.org>
> Cc: Juri Lelli <juri.lelli@redhat.com>
> Cc: Clark Williams <williams@redhat.com>
> Cc: John Kacur <jkacur@redhat.com>
> Cc: Peter Zijlstra <peterz@infradead.org>
> Cc: Thomas Gleixner <tglx@linutronix.de>
> Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
> Cc: Daniel Bristot de Oliveira <bristot@kernel.org>
> Cc: linux-rt-users@vger.kernel.org
> Cc: linux-trace-devel@vger.kernel.org
> Cc: linux-kernel@vger.kernel.org
> Signed-off-by: Daniel Bristot de Oliveira <bristot@kernel.org>
> ---
>  tools/tracing/rtla/src/trace.c | 192 +++++++++++++++
>  tools/tracing/rtla/src/trace.h |  27 ++
>  tools/tracing/rtla/src/utils.c | 433 +++++++++++++++++++++++++++++++++
>  tools/tracing/rtla/src/utils.h |  56 +++++
>  4 files changed, 708 insertions(+)
>  create mode 100644 tools/tracing/rtla/src/trace.c
>  create mode 100644 tools/tracing/rtla/src/trace.h
>  create mode 100644 tools/tracing/rtla/src/utils.c
>  create mode 100644 tools/tracing/rtla/src/utils.h
> 
> diff --git a/tools/tracing/rtla/src/trace.c b/tools/tracing/rtla/src/trace.c
> new file mode 100644
> index 000000000000..ab11c29cdcc2
> --- /dev/null
> +++ b/tools/tracing/rtla/src/trace.c
> @@ -0,0 +1,192 @@
> +// SPDX-License-Identifier: GPL-2.0
> +#define _GNU_SOURCE
> +#include <sys/sendfile.h>
> +#include <tracefs.h>
> +#include <signal.h>
> +#include <stdlib.h>
> +#include <unistd.h>
> +#include <errno.h>
> +
> +#include "trace.h"
> +#include "utils.h"
> +
> +/*
> + * enable_tracer_by_name - enable a tracer on the given instance
> + */
> +int enable_tracer_by_name(struct tracefs_instance *inst, const char *tracer)
> +{
> +	enum tracefs_tracers t;
> +	int retval;
> +
> +	t = TRACEFS_TRACER_CUSTOM;
> +
> +	debug_msg("enabling %s tracer\n", tracer);
> +
> +	retval = tracefs_tracer_set(inst, t, tracer);
> +	if (retval < 0) {
> +		if (errno == ENODEV)
> +			err_msg("tracer %s not found!\n", tracer);
> +
> +		err_msg("failed to enable the tracer %s\n", tracer);
> +		return -1;
> +	}
> +
> +	return 0;
> +}
> +
> +/*
> + * disable_tracer - set nop tracer to the insta
> + */
> +void disable_tracer(struct tracefs_instance *inst)
> +{
> +	enum tracefs_tracers t = TRACEFS_TRACER_NOP;
> +	int retval;
> +
> +	retval = tracefs_tracer_set(inst, t);
> +	if (retval < 0)
> +		err_msg("oops, error disabling tracer\n");
> +}
> +
> +/*
> + * create_instance - create a trace instance with *instance_name
> + */
> +struct tracefs_instance *create_instance(char *instance_name)
> +{
> +	return tracefs_instance_create(instance_name);
> +}
> +
> +/*
> + * destroy_instance - remove a trace instance and free the data
> + */
> +void destroy_instance(struct tracefs_instance *inst)
> +{
> +	tracefs_instance_destroy(inst);
> +	tracefs_instance_free(inst);
> +}
> +
> +/*
> + * save_trace_to_file - save the trace output of the instance to the file
> + */
> +int save_trace_to_file(struct tracefs_instance *inst, const char *filename)
> +{
> +	const char *file = "trace";
> +	mode_t mode = 0644;
> +	char *buffer[4096];
> +	int out_fd, in_fd;
> +	int retval = -1;
> +
> +	in_fd = tracefs_instance_file_open(inst, file, O_RDONLY);
> +	if (in_fd < 0) {
> +		err_msg("Failed to open trace file\n");
> +		return -1;
> +	}
> +
> +	out_fd = creat(filename, mode);
> +	if (out_fd < 0) {
> +		err_msg("Failed to create output file %s\n", filename);
> +		goto out_close_in;
> +	}
> +
> +	do {
> +		retval = read(in_fd, buffer, sizeof(buffer));
> +		if (retval <= 0)
> +			goto out_close;
> +
> +		retval = write(out_fd, buffer, retval);
> +		if (retval < 0)
> +			goto out_close;
> +	} while (retval > 0);
> +
> +	retval = 0;
> +out_close:
> +	close(out_fd);
> +out_close_in:
> +	close(in_fd);
> +	return retval;
> +}
> +
> +/*
> + * collect_registered_events - call the existing callback function for the event
> + *
> + * If an event has a registered callback function, call it.
> + * Otherwise, ignore the event.
> + */
> +int
> +collect_registered_events(struct tep_event *event, struct tep_record *record,
> +			  int cpu, void *context)
> +{
> +	struct trace_instance *trace = context;
> +	struct trace_seq *s = trace->seq;
> +
> +	if (!event->handler)
> +		return 0;
> +
> +	event->handler(s, record, event, context);
> +
> +	return 0;
> +}
> +
> +/*
> + * trace_instance_destroy - destroy and free a rtla trace instance
> + */
> +void trace_instance_destroy(struct trace_instance *trace)
> +{
> +	if (trace->inst) {
> +		disable_tracer(trace->inst);
> +		destroy_instance(trace->inst);
> +	}
> +
> +	if (trace->seq)
> +		free(trace->seq);
> +
> +	if (trace->tep)
> +		tep_free(trace->tep);
> +}
> +
> +/*
> + * trace_instance_init - create an rtla trace instance
> + *
> + * It is more than the tracefs instance, as it contains other
> + * things required for the tracing, such as the local events and
> + * a seq file.
> + *
> + * Note that the trace instance is returned disabled. This allows
> + * the tool to apply some other configs, like setting priority
> + * to the kernel threads, before starting generating trace entries.
> + */
> +int trace_instance_init(struct trace_instance *trace, char *tool_name)
> +{
> +	trace->seq = calloc(1, sizeof(*trace->seq));
> +	if (!trace->seq)
> +		goto out_err;
> +
> +	trace_seq_init(trace->seq);
> +
> +	trace->inst = create_instance(tool_name);
> +	if (!trace->inst)
> +		goto out_err;
> +
> +	trace->tep = tracefs_local_events(NULL);
> +	if (!trace->tep)
> +		goto out_err;
> +
> +	/*
> +	 * Let the main enable the record after setting some other
> +	 * things such as the priority of the tracer's threads.
> +	 */
> +	tracefs_trace_off(trace->inst);
> +
> +	return 0;
> +
> +out_err:
> +	trace_instance_destroy(trace);
> +	return 1;
> +}
> +
> +/*
> + * trace_instance_start - start tracing a given rtla instance
> + */
> +int trace_instance_start(struct trace_instance *trace)
> +{
> +	return tracefs_trace_on(trace->inst);
> +}
> diff --git a/tools/tracing/rtla/src/trace.h b/tools/tracing/rtla/src/trace.h
> new file mode 100644
> index 000000000000..7c3930909b70
> --- /dev/null
> +++ b/tools/tracing/rtla/src/trace.h
> @@ -0,0 +1,27 @@
> +// SPDX-License-Identifier: GPL-2.0
> +#include <tracefs.h>
> +#include <stddef.h>
> +
> +struct trace_instance {
> +	struct tracefs_instance		*inst;
> +	struct tep_handle		*tep;
> +	struct trace_seq		*seq;
> +};
> +
> +int trace_instance_init(struct trace_instance *trace, char *tool_name);
> +int trace_instance_start(struct trace_instance *trace);
> +void trace_instance_destroy(struct trace_instance *trace);
> +
> +struct trace_seq *get_trace_seq(void);
> +int enable_tracer_by_name(struct tracefs_instance *inst, const char *tracer);
> +void disable_tracer(struct tracefs_instance *inst);
> +
> +int enable_osnoise(struct trace_instance *trace);
> +int enable_timerlat(struct trace_instance *trace);
> +
> +struct tracefs_instance *create_instance(char *instance_name);
> +void destroy_instance(struct tracefs_instance *inst);
> +
> +int save_trace_to_file(struct tracefs_instance *inst, const char *filename);
> +int collect_registered_events(struct tep_event *tep, struct tep_record *record,
> +			      int cpu, void *context);
> diff --git a/tools/tracing/rtla/src/utils.c b/tools/tracing/rtla/src/utils.c
> new file mode 100644
> index 000000000000..4a35e62b1514
> --- /dev/null
> +++ b/tools/tracing/rtla/src/utils.c
> @@ -0,0 +1,433 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Copyright (C) 2021 Red Hat Inc, Daniel Bristot de Oliveira <bristot@kernel.org>
> + */
> +
> +#include <proc/readproc.h>
> +#include <stdarg.h>
> +#include <stdlib.h>
> +#include <string.h>
> +#include <unistd.h>
> +#include <ctype.h>
> +#include <errno.h>
> +#include <sched.h>
> +#include <stdio.h>
> +
> +#include "utils.h"
> +
> +#define MAX_MSG_LENGTH	1024
> +int config_debug;
> +
> +/*
> + * err_msg - print an error message to the stderr
> + */
> +void err_msg(const char *fmt, ...)
> +{
> +	char message[MAX_MSG_LENGTH];
> +	va_list ap;
> +
> +	va_start(ap, fmt);
> +	vsnprintf(message, sizeof(message), fmt, ap);
> +	va_end(ap);
> +
> +	fprintf(stderr, "%s", message);
> +}
> +
> +/*
> + * debug_msg - print a debug message to stderr if debug is set
> + */
> +void debug_msg(const char *fmt, ...)
> +{
> +	char message[MAX_MSG_LENGTH];
> +	va_list ap;
> +
> +	if (!config_debug)
> +		return;
> +
> +	va_start(ap, fmt);
> +	vsnprintf(message, sizeof(message), fmt, ap);
> +	va_end(ap);
> +
> +	fprintf(stderr, "%s", message);
> +}
> +
> +/*
> + * get_long_from_str - get a long int from a string
> + */
> +long get_long_from_str(char *start)
> +{
> +	long value;
> +	char *end;
> +
> +	errno = 0;
> +	value = strtol(start, &end, 10);
> +	if (errno || start == end)
> +		return -1;
> +
> +	return value;
> +}
> +
> +/*
> + * get_duration - fill output with a human readable duration since start_time
> + */
> +void get_duration(time_t start_time, char *output, int output_size)
> +{
> +	time_t now = time(NULL);
> +	struct tm *tm_info;
> +	time_t duration;
> +
> +	duration = difftime(now, start_time);
> +	tm_info = localtime(&duration);
> +
> +	snprintf(output, output_size, "%3d %02d:%02d:%02d",
> +			tm_info->tm_yday,
> +			tm_info->tm_hour - 1,
> +			tm_info->tm_min,
> +			tm_info->tm_sec);
> +}
> +
> +/*
> + * parse_cpu_list - parse a cpu_list filling a char vector with cpus set
> + *
> + * Receives a cpu list, like 1-3,5 (cpus 1, 2, 3, 5), and then set the char
> + * in the monitored_cpus.
> + *
> + * XXX: convert to a bitmask.
> + */
> +int parse_cpu_list(char *cpu_list, char **monitored_cpus)
> +{
> +	char *mon_cpus;
> +	const char *p;
> +	int end_cpu;
> +	int nr_cpus;
> +	int cpu;
> +	int i;
> +
> +	nr_cpus = sysconf(_SC_NPROCESSORS_CONF);
> +
> +	mon_cpus = malloc(nr_cpus * sizeof(char));
> +	memset(mon_cpus, 0, (nr_cpus * sizeof(char)));
> +
> +	for (p = cpu_list; *p; ) {
> +		cpu = atoi(p);
> +		if (cpu < 0 || (!cpu && *p != '0') || cpu >= nr_cpus)
> +			goto err;
> +
> +		while (isdigit(*p))
> +			p++;
> +		if (*p == '-') {
> +			p++;
> +			end_cpu = atoi(p);
> +			if (end_cpu < cpu || (!end_cpu && *p != '0') || end_cpu >= nr_cpus)
> +				goto err;
> +			while (isdigit(*p))
> +				p++;
> +		} else
> +			end_cpu = cpu;
> +
> +		if (cpu == end_cpu) {
> +			debug_msg("cpu_list: adding cpu %d\n", cpu);
> +			mon_cpus[cpu] = 1;
> +		} else {
> +			for (i = cpu; i <= end_cpu; i++) {
> +				debug_msg("cpu_list: adding cpu %d\n", i);
> +				mon_cpus[i] = 1;
> +			}
> +		}
> +
> +		if (*p == ',')
> +			p++;
> +	}
> +
> +	*monitored_cpus = mon_cpus;
> +
> +	return 0;
> +
> +err:
> +	debug_msg("Error parsing the cpu list %s", cpu_list);
> +	return 1;
> +}
> +
> +/*
> + * parse_duration - parse duration with s/m/h/d suffix converting it to seconds
> + */
> +long parse_seconds_duration(char *val)
> +{
> +	char *end;
> +	long t;
> +
> +	t = strtol(val, &end, 10);
> +
> +	if (end) {
> +		switch (*end) {
> +		case 's':
> +		case 'S':
> +			break;
> +		case 'm':
> +		case 'M':
> +			t *= 60;
> +			break;
> +		case 'h':
> +		case 'H':
> +			t *= 60 * 60;
> +			break;
> +
> +		case 'd':
> +		case 'D':
> +			t *= 24 * 60 * 60;
> +			break;
> +		}
> +	}
> +
> +	return t;
> +}
> +
> +/*
> + * parse_ns_duration - parse duration with ns/us/ms/s converting it to nanoseconds
> + */
> +long parse_ns_duration(char *val)
> +{
> +	char *end;
> +	long t;
> +
> +	t = strtol(val, &end, 10);
> +
> +	if (end) {
> +		if (!strncmp(end, "ns", 2)) {
> +			return t;
> +		} else if (!strncmp(end, "us", 2)) {
> +			t *= 1000;
> +			return t;
> +		} else if (!strncmp(end, "ms", 2)) {
> +			t *= 1000 * 1000;
> +			return t;
> +		} else if (!strncmp(end, "s", 1)) {
> +			t *= 1000 * 1000 * 100;
                               ^^^
Ah, 1000 not 100. 


Thanks,
Tao
> +		}
> +		return -1;
> +	}
> +
> +	return t;
> +}
> +
> +/*
> + * This is a set of helper functions to use SCHED_DEADLINE.
> + */
> +#ifdef __x86_64__
> +# define __NR_sched_setattr	314
> +# define __NR_sched_getattr	315
> +#elif __i386__
> +# define __NR_sched_setattr	351
> +# define __NR_sched_getattr	352
> +#elif __arm__
> +# define __NR_sched_setattr	380
> +# define __NR_sched_getattr	381
> +#elif __aarch64__
> +# define __NR_sched_setattr	274
> +# define __NR_sched_getattr	275
> +#elif __powerpc__
> +# define __NR_sched_setattr	355
> +# define __NR_sched_getattr	356
> +#elif __s390x__
> +# define __NR_sched_setattr	345
> +# define __NR_sched_getattr	346
> +#endif
> +
> +#define SCHED_DEADLINE		6
> +
> +static inline int sched_setattr(pid_t pid, const struct sched_attr *attr,
> +				unsigned int flags) {
> +	return syscall(__NR_sched_setattr, pid, attr, flags);
> +}
> +
> +static inline int sched_getattr(pid_t pid, struct sched_attr *attr,
> +				unsigned int size, unsigned int flags)
> +{
> +	return syscall(__NR_sched_getattr, pid, attr, size, flags);
> +}
> +
> +int __set_sched_attr(int pid, struct sched_attr *attr)
> +{
> +	int flags = 0;
> +	int retval;
> +
> +	retval = sched_setattr(pid, attr, flags);
> +	if (retval < 0) {
> +		err_msg("boost_with_deadline failed to boost pid %d: %s\n",
> +			pid, strerror(errno));
> +		return 1;
> +	}
> +
> +	return 0;
> +}
> +/*
> + * set_comm_sched_attr - set sched params to threads starting with char *comm
> + *
> + * This function uses procps to list the currently running threads and then
> + * set the sched_attr *attr to the threads that start with char *comm. It is
> + * mainly used to set the priority to the kernel threads created by the
> + * tracers.
> + */
> +int set_comm_sched_attr(const char *comm, struct sched_attr *attr)
> +{
> +	int flags = PROC_FILLCOM | PROC_FILLSTAT;
> +	PROCTAB *ptp;
> +	proc_t task;
> +	int retval;
> +
> +	ptp = openproc(flags);
> +	if (!ptp) {
> +		err_msg("error openproc()\n");
> +		return -ENOENT;
> +	}
> +
> +	memset(&task, 0, sizeof(task));
> +
> +	while (readproc(ptp, &task)) {
> +		retval = strncmp(comm, task.cmd, strlen(comm));
> +		if (retval)
> +			continue;
> +		retval = __set_sched_attr(task.tid, attr);
> +		if (retval)
> +			goto out_err;
> +	}
> +
> +	closeproc(ptp);
> +	return 0;
> +
> +out_err:
> +	closeproc(ptp);
> +	return 1;
> +}
> +
> +#define INVALID_VAL	(~0L)
> +static long get_long_ns_after_colon(char *start)
> +{
> +	long val = INVALID_VAL;
> +
> +	/* find the ":" */
> +	start = strstr(start, ":");
> +	if (!start)
> +		return -1;
> +
> +	/* skip ":" */
> +	start++;
> +	val = parse_ns_duration(start);
> +
> +	return val;
> +}
> +
> +static long get_long_after_colon(char *start)
> +{
> +	long val = INVALID_VAL;
> +
> +	/* find the ":" */
> +	start = strstr(start, ":");
> +	if (!start)
> +		return -1;
> +
> +	/* skip ":" */
> +	start++;
> +	val = get_long_from_str(start);
> +
> +	return val;
> +}
> +
> +/*
> + * parse priority in the format:
> + * SCHED_OTHER:
> + *		o:<prio>
> + *		O:<prio>
> + * SCHED_RR:
> + *		r:<prio>
> + *		R:<prio>
> + * SCHED_FIFO:
> + *		f:<prio>
> + *		F:<prio>
> + * SCHED_DEADLINE:
> + *		d:runtime:period
> + *		D:runtime:period
> + */
> +int parse_prio(char *arg, struct sched_attr *sched_param)
> +{
> +	long prio;
> +	long runtime;
> +	long period;
> +
> +	memset(sched_param, 0, sizeof(*sched_param));
> +	sched_param->size = sizeof(*sched_param);
> +
> +	switch (arg[0]) {
> +	case 'd':
> +	case 'D':
> +		/* d:runtime:period */
> +		if (strlen(arg) < 4)
> +			return -1;
> +
> +		runtime = get_long_ns_after_colon(arg);
> +		if (runtime == INVALID_VAL)
> +			return -1;
> +
> +		period = get_long_ns_after_colon(&arg[2]);
> +		if (period == INVALID_VAL)
> +			return -1;
> +
> +		if (runtime > period)
> +			return -1;
> +
> +		sched_param->sched_policy   = SCHED_DEADLINE;
> +		sched_param->sched_runtime  = runtime;
> +		sched_param->sched_deadline = period;
> +		sched_param->sched_period   = period;
> +		break;
> +	case 'f':
> +	case 'F':
> +		/* f:prio */
> +		prio = get_long_after_colon(arg);
> +		if (prio == INVALID_VAL)
> +			return -1;
> +
> +		if (prio < sched_get_priority_min(SCHED_FIFO))
> +			return -1;
> +		if (prio > sched_get_priority_max(SCHED_FIFO))
> +			return -1;
> +
> +		sched_param->sched_policy   = SCHED_FIFO;
> +		sched_param->sched_priority = prio;
> +		break;
> +	case 'r':
> +	case 'R':
> +		/* r:prio */
> +		prio = get_long_after_colon(arg);
> +		if (prio == INVALID_VAL)
> +			return -1;
> +
> +		if (prio < sched_get_priority_min(SCHED_RR))
> +			return -1;
> +		if (prio > sched_get_priority_max(SCHED_RR))
> +			return -1;
> +
> +		sched_param->sched_policy   = SCHED_RR;
> +		sched_param->sched_priority = prio;
> +		break;
> +	case 'o':
> +	case 'O':
> +		/* o:prio */
> +		prio = get_long_after_colon(arg);
> +		if (prio == INVALID_VAL)
> +			return -1;
> +
> +		if (prio < sched_get_priority_min(SCHED_OTHER))
> +			return -1;
> +		if (prio > sched_get_priority_max(SCHED_OTHER))
> +			return -1;
> +
> +		sched_param->sched_policy   = SCHED_OTHER;
> +		sched_param->sched_priority = prio;
> +		break;
> +	default:
> +		return -1;
> +	}
> +	return 0;
> +}
> diff --git a/tools/tracing/rtla/src/utils.h b/tools/tracing/rtla/src/utils.h
> new file mode 100644
> index 000000000000..2bce867387b4
> --- /dev/null
> +++ b/tools/tracing/rtla/src/utils.h
> @@ -0,0 +1,56 @@
> +// SPDX-License-Identifier: GPL-2.0
> +#include <stdint.h>
> +#include <time.h>
> +
> +/*
> + * '18446744073709551615\0'
> + */
> +#define BUFF_U64_STR_SIZE	24
> +
> +#define container_of(ptr, type, member)({			\
> +	const typeof(((type *)0)->member) *__mptr = (ptr);	\
> +	(type *)((char *)__mptr - offsetof(type, member)) ; })
> +
> +extern int config_debug;
> +void debug_msg(const char *fmt, ...);
> +void err_msg(const char *fmt, ...);
> +
> +long parse_seconds_duration(char *val);
> +void get_duration(time_t start_time, char *output, int output_size);
> +
> +int parse_cpu_list(char *cpu_list, char **monitored_cpus);
> +long get_long_from_str(char *start);
> +
> +static inline void
> +update_min(unsigned long long *a, unsigned long long *b)
> +{
> +	if (*a > *b)
> +		*a = *b;
> +}
> +
> +static inline void
> +update_max(unsigned long long *a, unsigned long long *b)
> +{
> +	if (*a < *b)
> +		*a = *b;
> +}
> +
> +static inline void
> +update_sum(unsigned long long *a, unsigned long long *b)
> +{
> +	*a += *b;
> +}
> +
> +struct sched_attr {
> +	uint32_t size;
> +	uint32_t sched_policy;
> +	uint64_t sched_flags;
> +	int32_t sched_nice;
> +	uint32_t sched_priority;
> +	uint64_t sched_runtime;
> +	uint64_t sched_deadline;
> +	uint64_t sched_period;
> +};
> +
> +int parse_prio(char *arg, struct sched_attr *sched_param);
> +int set_comm_sched_attr(const char *comm, struct sched_attr *attr);
> -- 
> 2.31.1