# libtracecmd(3) Manual Page

## NAME

libtracecmd - 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_iterate_events_reverse(struct tracecmd_input *handle,
                                        cpu_set_t *cpus, int cpu_size,
                                        int (*callback)(struct tracecmd_input *,
                                                        struct tep_record *,
                                                        int, void *),
                                        void *callback_data, bool cont);
            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);
            int tracecmd_follow_missed_events(struct tracecmd_input *handle,
                                               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);
            int *tracecmd_iterate_reset(struct tracecmd_input *handle);

    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);
            int tracecmd_get_tsc2nsec(struct tracecmd_input *handle, int *mult, int pass[]shift, unsigned 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>
    Tzvetomir Stoyanov <tz.stoyanov@gmail.com>

## REPORTING BUGS

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

## 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).