libtracecmd - Man Page

trace-cmd library APIs

Synopsis

#include <trace-cmd.h>

Open and close trace file:
        struct tracecmd_input *tracecmd_open(const char *file, int flags);
        struct tracecmd_input *tracecmd_open_fd(int fd, int flags);
        struct tracecmd_input *tracecmd_open_head(const char *file, int flags);
        void tracecmd_close(struct tracecmd_input *handle);
        void tracecmd_set_private(struct tracecmd_input *handle, void *data);
        void *tracecmd_get_private(struct tracecmd_input *handle);

Read tracing records from a trace file:
        int tracecmd_init_data(struct tracecmd_input *handle);
        struct tep_record *tracecmd_read_cpu_first(struct tracecmd_input *handle, int cpu);
        struct tep_record *tracecmd_read_data(struct tracecmd_input *handle, int cpu);
        struct tep_record *tracecmd_read_at(struct tracecmd_input *handle, unsigned long long offset, int *cpu);
        void tracecmd_free_record(struct tep_record *record);
        struct tep_handle *tracecmd_get_tep(struct tracecmd_input *handle);

Iterating over events in a trace file:
        int tracecmd_iterate_events(struct tracecmd_input *handle,
                                    cpu_set_t *cpus, int cpu_size,
                                    int (*callback)(struct tracecmd_input *,
                                                    struct tep_record *,
                                                    int, void *),
                                    void *callback_data);
        int tracecmd_iterate_events_multi(struct tracecmd_input **handles,
                                          int nr_handles,
                                          int (*callback)(struct tracecmd_input *,
                                                                   struct tep_record *,
                                                           int, void *),
                                          void *callback_data);
        int tracecmd_follow_event(struct tracecmd_input *handle,
                                  const char *system, const char *event_name,
                                  int (*callback)(struct tracecmd_input *,
                                                  struct tep_event *,
                                                  struct tep_record *,
                                                  int, void *),
                                  void *callback_data);
        struct tracecmd_filter *tracecmd_filter_add(struct tracecmd_input handle,
                                                    const char *filter_str, bool neg);

Read tracing instances from a trace file:
        int *tracecmd_buffer_instances(struct tracecmd_input *handle);
        const char *tracecmd_buffer_instance_name(struct tracecmd_input *handle, int indx);
        struct tracecmd_input *tracecmd_buffer_instance_handle(struct tracecmd_input *handle, int indx);

Handle time stamps from a trace file:
        unsigned long long tracecmd_get_first_ts(struct tracecmd_input *handle);
        void tracecmd_add_ts_offset(struct tracecmd_input *handle, long long offset);

Get traceing peer information from a trace file:
        unsigned long long tracecmd_get_traceid(struct tracecmd_input *handle);
        int tracecmd_get_guest_cpumap(struct tracecmd_input *handle, unsigned long long trace_id, const char **name, int *vcpu_count, const int **cpu_pid);

Mapping host and guest trace files:
        int tracecmd_map_vcpus(struct tracecmd_input **handles, int nr_handles);
        struct tracecmd_cpu_map *tracecmd_get_cpu_map(struct tracecmd_input *handle, int cpu);
        struct tracecmd_cpu_map *tracecmd_map_find_by_host_pid(struct tracecmd_input *handle,
                                                      int host_pid);
        int tracecmd_map_get_host_pid(struct tracecmd_cpu_map *map);
        struct tracecmd_input *tracecmd_map_get_guest(struct tracecmd_cpu_map *map);
        void tracecmd_map_set_private(struct tracecmd_cpu_map *map, void *priv);
        void *tracecmd_map_get_private(struct tracecmd_cpu_map *map);

Control library logs:
        int tracecmd_set_loglevel(enum tep_loglevel level);

Description

The libtracecmd(3) library provides APIs to read, parse and write trace-cmd.dat(5) files, recorded with trace-cmd(1) application and containing tracing information from ftrace, the official Linux kernel tracer.

Files

trace-cmd.h
        Header file to include in order to have access to the library APIs.
-ltracecmd
        Linker switch to add when building a program that uses the library.

See Also

libtraceevent(3) libtracefs(3) trace-cmd(1) trace-cmd.dat(5)

Author

Steven Rostedt <rostedt@goodmis.org[1]>
Tzvetomir Stoyanov <tz.stoyanov@gmail.com[2]>

Reporting Bugs

Report bugs to <linux-trace-devel@vger.kernel.org[3]>

License

libtracecmd is Free Software licensed under the GNU LGPL 2.1

Resources

https://git.kernel.org/pub/scm/utils/trace-cmd/trace-cmd.git/

Copying

Copyright (C) 2020 VMware, Inc. Free use of this software is granted under the terms of the GNU Public License (GPL).

Notes

  1. rostedt@goodmis.org
    mailto:rostedt@goodmis.org
  2. tz.stoyanov@gmail.com
    mailto:tz.stoyanov@gmail.com
  3. linux-trace-devel@vger.kernel.org
    mailto:linux-trace-devel@vger.kernel.org

Info

10/11/2022 libtracefs Manual