Re: [PATCH V6 08/20] rtla: Helper functions for rtla
From: Tao Zhou
Date: Wed Oct 27 2021 - 10:02:08 EST
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@xxxxxxxxxxx>
> Cc: Ingo Molnar <mingo@xxxxxxxxxx>
> Cc: Tom Zanussi <zanussi@xxxxxxxxxx>
> Cc: Masami Hiramatsu <mhiramat@xxxxxxxxxx>
> Cc: Juri Lelli <juri.lelli@xxxxxxxxxx>
> Cc: Clark Williams <williams@xxxxxxxxxx>
> Cc: John Kacur <jkacur@xxxxxxxxxx>
> Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
> Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
> Cc: Sebastian Andrzej Siewior <bigeasy@xxxxxxxxxxxxx>
> Cc: Daniel Bristot de Oliveira <bristot@xxxxxxxxxx>
> Cc: linux-rt-users@xxxxxxxxxxxxxxx
> Cc: linux-trace-devel@xxxxxxxxxxxxxxx
> Cc: linux-kernel@xxxxxxxxxxxxxxx
> Signed-off-by: Daniel Bristot de Oliveira <bristot@xxxxxxxxxx>
> ---
> 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@xxxxxxxxxx>
> + */
> +
> +#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