tests/lib/test_heavy_thread.c

   1 /*
   2  * $Id: heavy-thread.c,v 1.2 2005/04/25 16:42:24 paul Exp $
   3  *
   4  * This file is part of Quagga.
   5  *
   6  * Quagga is free software; you can redistribute it and/or modify it
   7  * under the terms of the GNU General Public License as published by the
   8  * Free Software Foundation; either version 2, or (at your option) any
   9  * later version.
  10  *
  11  * Quagga is distributed in the hope that it will be useful, but
  12  * WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14  * General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU General Public License
  17  * along with Quagga; see the file COPYING.  If not, write to the Free
  18  * Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
  19  * 02111-1307, USA.
  20  */
  21
  22 /* This programme shows the effects of 'heavy' long-running functions
  23  * on the cooperative threading model, as demonstrated by heavy.c, and how
  24  * they can be mitigated using a background thread.
  25  *
  26  * Run it with a config file containing 'password whatever', telnet to it
  27  * (it defaults to port 4000) and enter the 'clear foo string' command.
  28  * then type whatever and observe that, unlike heavy.c, the vty interface
  29  * remains responsive.
  30  */
  31 #include <zebra.h>
  32 #include <math.h>
  33
  34 #include "thread.h"
  35 #include "vty.h"
  36 #include "command.h"
  37 #include "memory.h"
  38 #include "log.h"
  39
  40 #include "tests.h"
  41
  42 extern struct thread_master *master;
  43
  44 enum
  45 {
  46   ITERS_FIRST = 0,
  47   ITERS_ERR = 100,
  48   ITERS_LATER = 400,
  49   ITERS_PRINT = 10,
  50   ITERS_MAX = 1000,
  51 };
  52
  53 struct work_state {
  54   struct vty *vty;
  55   char *str;
  56   int i;
  57 };
  58
  59 static void
  60 slow_func (struct vty *vty, const char *str, const int i)
  61 {
  62   double x = 1;
  63   int j;
  64
  65   for (j = 0; j < 300; j++)
  66     x += sin(x)*j;
  67
  68   if ((i % ITERS_LATER) == 0)
  69     printf ("%s: %d, temporary error, save this somehow and do it later..\n",
  70             __func__, i);
  71
  72   if ((i % ITERS_ERR) == 0)
  73     printf ("%s: hard error\n", __func__);
  74
  75   if ((i % ITERS_PRINT) == 0)
  76     printf ("%s did %d, x = %g\n", str, i, x);
  77 }
  78
  79 static int
  80 clear_something (struct thread *thread)
  81 {
  82   struct work_state *ws = THREAD_ARG(thread);
  83
  84   /* this could be like iterating through 150k of route_table
  85    * or worse, iterating through a list of peers, to bgp_stop them with
  86    * each having 150k route tables to process...
  87    */
  88   while (ws->i < ITERS_MAX)
  89     {
  90       slow_func(ws->vty, ws->str, ws->i);
  91       ws->i++;
  92       if (thread_should_yield(thread))
  93         {
  94           thread_add_background(master, clear_something, ws, 0);
  95           return 0;
  96         }
  97     }
  98
  99   /* All done! */
 100   XFREE (MTYPE_TMP, ws->str);
 101   XFREE (MTYPE_TMP, ws);
 102   return 0;
 103 }
 104
 105 DEFUN (clear_foo,
 106        clear_foo_cmd,
 107        "clear foo LINE...",
 108        "clear command\n"
 109        "arbitrary string\n")
 110 {
 111   char *str;
 112   struct work_state *ws;
 113
 114   if (!argc)
 115     {
 116       vty_out (vty, "%% string argument required%s", VTY_NEWLINE);
 117       return CMD_WARNING;
 118     }
 119
 120   str = argv_concat (argv, argc, 0);
 121
 122   if ((ws = XMALLOC(MTYPE_TMP, sizeof(*ws))) == NULL)
 123     {
 124       zlog_err ("%s: unable to allocate work_state", __func__);
 125       return CMD_WARNING;
 126     }
 127
 128   if (!(ws->str = XSTRDUP (MTYPE_TMP, str)))
 129     {
 130       zlog_err ("%s: unable to xstrdup", __func__);
 131       XFREE (MTYPE_TMP, ws);
 132       return CMD_WARNING;
 133     }
 134
 135   ws->vty = vty;
 136   ws->i = ITERS_FIRST;
 137
 138   thread_add_background(master, clear_something, ws, 0);
 139
 140   return CMD_SUCCESS;
 141 }
 142
 143 void
 144 test_init()
 145 {
 146   install_element (VIEW_NODE, &clear_foo_cmd);
 147 }