tracefs_hist_start(3) — Linux manual page

NAME | SYNOPSIS | DESCRIPTION | RETURN VALUE | EXAMPLE | FILES | SEE ALSO | AUTHOR | REPORTING BUGS | LICENSE | RESOURCES | COPYING | NOTES | COLOPHON

LIBTRACEFS(3)               libtracefs Manual              LIBTRACEFS(3)

NAME         top

       tracefs_hist_start, tracefs_hist_destroy, tracefs_hist_pause,
       tracefs_hist_continue, tracefs_hist_reset - Pause, continue, or
       clear an existing histogram

SYNOPSIS         top

       #include <tracefs.h>

       int tracefs_hist_start(struct tracefs_instance *instance, struct tracefs_hist *hist);
       int tracefs_hist_destroy(struct tracefs_instance *instance, struct tracefs_hist *hist);
       int tracefs_hist_pause(struct tracefs_instance *instance, struct tracefs_hist *hist);
       int tracefs_hist_continue(struct tracefs_instance *instance, struct tracefs_hist *hist);
       int tracefs_hist_reset(struct tracefs_instance *instance, struct tracefs_hist *hist);

DESCRIPTION         top

       tracefs_hist_start() is called to actually start the histogram
       hist. The instance is the instance to start the histogram in,
       NULL if it should start at the top level.

       tracefs_hist_pause() is called to pause the histogram hist. The
       instance is the instance to pause the histogram in, NULL if it is
       in the top level.

       tracefs_hist_continue() is called to continue a paused histogram
       hist. The instance is the instance to continue the histogram,
       NULL if it is in the top level.

       tracefs_hist_reset() is called to clear / reset the histogram
       hist. The instance is the instance to clear the histogram, NULL
       if it is in the top level.

       tracefs_hist_destroy() is called to delete the histogram where it
       will no longer exist. The instance is the instance to delete the
       histogram from, NULL if it is in the top level.

RETURN VALUE         top

       All the return zero on success or -1 on error.

EXAMPLE         top

           #include <stdlib.h>
           #include <tracefs.h>

           enum commands {
                   START,
                   PAUSE,
                   CONT,
                   RESET,
                   DELETE,
                   SHOW,
           };

           int main (int argc, char **argv, char **env)
           {
                   struct tracefs_instance *instance;
                   struct tracefs_hist *hist;
                   struct tep_handle *tep;
                   enum commands cmd;
                   char *cmd_str;
                   int ret;

                   if (argc < 2) {
                           fprintf(stderr, "usage: %s command\n", argv[0]);
                           exit(-1);
                   }

                   cmd_str = argv[1];

                   if (!strcmp(cmd_str, "start"))
                           cmd = START;
                   else if (!strcmp(cmd_str, "pause"))
                           cmd = PAUSE;
                   else if (!strcmp(cmd_str, "cont"))
                           cmd = CONT;
                   else if (!strcmp(cmd_str, "reset"))
                           cmd = RESET;
                   else if (!strcmp(cmd_str, "delete"))
                           cmd = DELETE;
                   else if (!strcmp(cmd_str, "show"))
                           cmd = SHOW;
                   else {
                           fprintf(stderr, "Unknown command %s\n", cmd_str);
                           exit(-1);
                   }

                   tep = tracefs_local_events(NULL);
                   if (!tep) {
                           perror("Reading tracefs");
                           exit(-1);
                   }

                   instance = tracefs_instance_create("hist_test");
                   if (!instance) {
                           fprintf(stderr, "Failed instance create\n");
                           exit(-1);
                   }

                   hist = tracefs_hist_alloc_2d(tep, "kmem", "kmalloc",
                                                "call_site",TRACEFS_HIST_KEY_SYM,
                                                "bytes_req", 0);
                   if (!hist) {
                           fprintf(stderr, "Failed hist create\n");
                           exit(-1);
                   }

                   ret = tracefs_hist_add_value(hist, "bytes_alloc");
                   ret |= tracefs_hist_add_sort_key(hist, "bytes_req");
                   ret |= tracefs_hist_add_sort_key(hist, "bytes_alloc");

                   ret |= tracefs_hist_sort_key_direction(hist, "bytes_alloc",
                                                          TRACEFS_HIST_SORT_DESCENDING);
                   if (ret) {
                           fprintf(stderr, "Failed modifying histogram\n");
                           exit(-1);
                   }

                   tracefs_error_clear(instance);

                   switch (cmd) {
                   case START:
                           ret = tracefs_hist_start(instance, hist);
                           if (ret) {
                                   char *err = tracefs_error_last(instance);
                                   if (err)
                                           fprintf(stderr, "\n%s\n", err);
                           }
                           break;
                   case PAUSE:
                           ret = tracefs_hist_pause(instance, hist);
                           break;
                   case CONT:
                           ret = tracefs_hist_continue(instance, hist);
                           break;
                   case RESET:
                           ret = tracefs_hist_reset(instance, hist);
                           break;
                   case DELETE:
                           ret = tracefs_hist_destroy(instance, hist);
                           break;
                   case SHOW: {
                           char *content;
                           content = tracefs_event_file_read(instance, "kmem", "kmalloc",
                                                             "hist", NULL);
                           ret = content ? 0 : -1;
                           if (content) {
                                   printf("%s\n", content);
                                   free(content);
                           }
                           break;
                   }
                   }
                   if (ret)
                           fprintf(stderr, "Failed: command\n");
                   exit(ret);
           }

FILES         top

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

SEE ALSO         top

       libtracefs(3), libtraceevent(3), trace-cmd(1),
       tracefs_hist_alloc(3), tracefs_hist_alloc_2d(3),
       tracefs_hist_alloc_nd(3), tracefs_hist_free(3),
       tracefs_hist_add_key(3), tracefs_hist_add_value(3),
       tracefs_hist_add_name(3), tracefs_hist_start(3),
       tracefs_hist_destory(3), tracefs_hist_add_sort_key(3),
       tracefs_hist_sort_key_direction(3)

AUTHOR         top

           Steven Rostedt <rostedt@goodmis.org[1]>
           Tzvetomir Stoyanov <tz.stoyanov@gmail.com[2]>
           sameeruddin shaik <sameeruddin.shaik8@gmail.com[3]>

REPORTING BUGS         top

       Report bugs to <linux-trace-devel@vger.kernel.org[4]>

LICENSE         top

       libtracefs is Free Software licensed under the GNU LGPL 2.1

RESOURCES         top

       https://git.kernel.org/pub/scm/libs/libtrace/libtracefs.git/ 

COPYING         top

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

NOTES         top

        1. rostedt@goodmis.org
           mailto:rostedt@goodmis.org

        2. tz.stoyanov@gmail.com
           mailto:tz.stoyanov@gmail.com

        3. sameeruddin.shaik8@gmail.com
           mailto:sameeruddin.shaik8@gmail.com

        4. linux-trace-devel@vger.kernel.org
           mailto:linux-trace-devel@vger.kernel.org

COLOPHON         top

       This page is part of the libtracefs (Linux kernel trace file
       system library) project.  Information about the project can be
       found at ⟨https://www.trace-cmd.org/⟩.  If you have a bug report
       for this manual page, see ⟨https://www.trace-cmd.org/⟩.  This
       page was obtained from the project's upstream Git repository
       ⟨https://git.kernel.org/pub/scm/libs/libtrace/libtracefs.git⟩ on
       2024-06-14.  (At that time, the date of the most recent commit
       that was found in the repository was 2024-05-17.)  If you
       discover any rendering problems in this HTML version of the page,
       or you believe there is a better or more up-to-date source for
       the page, or you have corrections or improvements to the
       information in this COLOPHON (which is not part of the original
       manual page), send a mail to man-pages@man7.org

libtracefs 1.7.0               12/22/2023                  LIBTRACEFS(3)

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