diff options
Diffstat (limited to 'tools/tracing/rtla/src/trace.c')
| -rw-r--r-- | tools/tracing/rtla/src/trace.c | 192 |
1 files changed, 192 insertions, 0 deletions
diff --git a/tools/tracing/rtla/src/trace.c b/tools/tracing/rtla/src/trace.c new file mode 100644 index 000000000000..107a0c6387f7 --- /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_name) +{ + enum tracefs_tracers tracer; + int retval; + + tracer = TRACEFS_TRACER_CUSTOM; + + debug_msg("enabling %s tracer\n", tracer_name); + + retval = tracefs_tracer_set(inst, tracer, tracer_name); + if (retval < 0) { + if (errno == ENODEV) + err_msg("tracer %s not found!\n", tracer_name); + + err_msg("failed to enable the tracer %s\n", tracer_name); + 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); +} |