tests/lib/test_heavy_thread.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  */
   4
   5 /* This programme shows the effects of 'heavy' long-running functions
   6  * on the cooperative threading model, as demonstrated by heavy.c, and how
   7  * they can be mitigated using a background thread.
   8  *
   9  * Run it with a config file containing 'password whatever', telnet to it
  10  * (it defaults to port 4000) and enter the 'clear foo string' command.
  11  * then type whatever and observe that, unlike heavy.c, the vty interface
  12  * remains responsive.
  13  */
  14 #include <zebra.h>
  15 #include <math.h>
  16
  17 #include "thread.h"
  18 #include "vty.h"
  19 #include "command.h"
  20 #include "memory.h"
  21 #include "log.h"
  22
  23 #include "tests.h"
  24
  25 extern struct thread_master *master;
  26
  27 enum { ITERS_FIRST = 0,
  28        ITERS_ERR = 100,
  29        ITERS_LATER = 400,
  30        ITERS_PRINT = 10,
  31        ITERS_MAX = 1000,
  32 };
  33
  34 struct work_state {
  35         struct vty *vty;
  36         char *str;
  37         int i;
  38 };
  39
  40 static void slow_func(struct vty *vty, const char *str, const int i)
  41 {
  42         double x = 1;
  43         int j;
  44
  45         for (j = 0; j < 300; j++)
  46                 x += sin(x) * j;
  47
  48         if ((i % ITERS_LATER) == 0)
  49                 printf("%s: %d, temporary error, save this somehow and do it later..\n",
  50                        __func__, i);
  51
  52         if ((i % ITERS_ERR) == 0)
  53                 printf("%s: hard error\n", __func__);
  54
  55         if ((i % ITERS_PRINT) == 0)
  56                 printf("%s did %d, x = %g\n", str, i, x);
  57 }
  58
  59 static void clear_something(struct thread *thread)
  60 {
  61         struct work_state *ws = THREAD_ARG(thread);
  62
  63         /* this could be like iterating through 150k of route_table
  64          * or worse, iterating through a list of peers, to bgp_stop them with
  65          * each having 150k route tables to process...
  66          */
  67         while (ws->i < ITERS_MAX) {
  68                 slow_func(ws->vty, ws->str, ws->i);
  69                 ws->i++;
  70                 if (thread_should_yield(thread)) {
  71                         thread_add_timer_msec(master, clear_something, ws, 0,
  72                                               NULL);
  73                         return;
  74                 }
  75         }
  76
  77         /* All done! */
  78         XFREE(MTYPE_TMP, ws->str);
  79         XFREE(MTYPE_TMP, ws);
  80 }
  81
  82 DEFUN (clear_foo,
  83        clear_foo_cmd,
  84        "clear foo LINE...",
  85        "clear command\n"
  86        "arbitrary string\n")
  87 {
  88         char *str;
  89         struct work_state *ws;
  90
  91         if (!argc) {
  92                 vty_out(vty, "%% string argument required\n");
  93                 return CMD_WARNING;
  94         }
  95
  96         str = argv_concat(argv, argc, 0);
  97
  98         ws = XMALLOC(MTYPE_TMP, sizeof(*ws));
  99
 100         ws->str = XSTRDUP(MTYPE_TMP, str);
 101
 102         ws->vty = vty;
 103         ws->i = ITERS_FIRST;
 104
 105         thread_add_timer_msec(master, clear_something, ws, 0, NULL);
 106
 107         return CMD_SUCCESS;
 108 }
 109
 110 void test_init(void)
 111 {
 112         install_element(VIEW_NODE, &clear_foo_cmd);
 113 }