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NAME |SYNOPSIS |DESCRIPTION |RETURN VALUE |EXAMPLE |FILES |SEE ALSO |AUTHOR |REPORTING BUGS |LICENSE |RESOURCES |COPYING |NOTES |COLOPHON | |
LIBTRACEFS(3) libtracefs ManualLIBTRACEFS(3)tracefs_hist_start, tracefs_hist_destroy, tracefs_hist_pause, tracefs_hist_continue, tracefs_hist_reset - Pause, continue, or clear an existing histogram
#include <tracefs.h> inttracefs_hist_start(struct tracefs_instance *instance, struct tracefs_hist *hist); inttracefs_hist_destroy(struct tracefs_instance *instance, struct tracefs_hist *hist); inttracefs_hist_pause(struct tracefs_instance *instance, struct tracefs_hist *hist); inttracefs_hist_continue(struct tracefs_instance *instance, struct tracefs_hist *hist); inttracefs_hist_reset(struct tracefs_instance *instance, struct tracefs_hist *hist);
tracefs_hist_start()is called to actually start the histogramhist. Theinstance 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 histogramhist. Theinstance 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 histogramhist. Theinstance is the instance to continue the histogram, NULL if it is in the top level.tracefs_hist_reset()is called to clear / reset the histogramhist. Theinstance 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. Theinstance is the instance to delete the histogram from, NULL if it is in the top level.
All the return zero on success or -1 on error.
#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); }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.
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)
Steven Rostedt<rostedt@goodmis.org[1]>Tzvetomir Stoyanov<tz.stoyanov@gmail.com[2]>sameeruddin shaik<sameeruddin.shaik8@gmail.com[3]>
Report bugs to <linux-trace-devel@vger.kernel.org[4]>
libtracefs is Free Software licensed under the GNU LGPL 2.1
https://git.kernel.org/pub/scm/libs/libtrace/libtracefs.git/
Copyright (C) 2020 VMware, Inc. Free use of this software is granted under the terms of the GNU Public License (GPL).
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
This page is part of thelibtracefs (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 2025-08-11. (At that time, the date of the most recent commit that was found in the repository was 2025-06-02.) 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 isnot part of the original manual page), send a mail to man-pages@man7.orglibtracefs 1.7.0 12/22/2023LIBTRACEFS(3)Pages that refer to this page:tracefs_filter_pid_function(3), tracefs_filter_string_append(3), tracefs_hist_add_sort_key(3), tracefs_hist_alloc(3), tracefs_hist_start(3), tracefs_sql(3), tracefs_synth_alloc(3), tracefs_synth_create(3), tracefs_synth_echo_cmd(3)
HTML rendering created 2025-09-06 byMichael Kerrisk, author ofThe Linux Programming Interface. For details of in-depthLinux/UNIX system programming training courses that I teach, lookhere. Hosting byjambit GmbH. | |