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 { ITERS_FIRST = 0,
  45        ITERS_ERR = 100,
  46        ITERS_LATER = 400,
  47        ITERS_PRINT = 10,
  48        ITERS_MAX = 1000,
  49 };
  50
  51 struct work_state {
  52         struct vty *vty;
  53         char *str;
  54         int i;
  55 };
  56
  57 static void slow_func(struct vty *vty, const char *str, const int i)
  58 {
  59         double x = 1;
  60         int j;
  61
  62         for (j = 0; j < 300; j++)
  63                 x += sin(x) * j;
  64
  65         if ((i % ITERS_LATER) == 0)
  66                 printf("%s: %d, temporary error, save this somehow and do it later..\n",
  67                        __func__, i);
  68
  69         if ((i % ITERS_ERR) == 0)
  70                 printf("%s: hard error\n", __func__);
  71
  72         if ((i % ITERS_PRINT) == 0)
  73                 printf("%s did %d, x = %g\n", str, i, x);
  74 }
  75
  76 static int clear_something(struct thread *thread)
  77 {
  78         struct work_state *ws = THREAD_ARG(thread);
  79
  80         /* this could be like iterating through 150k of route_table
  81          * or worse, iterating through a list of peers, to bgp_stop them with
  82          * each having 150k route tables to process...
  83          */
  84         while (ws->i < ITERS_MAX) {
  85                 slow_func(ws->vty, ws->str, ws->i);
  86                 ws->i++;
  87                 if (thread_should_yield(thread)) {
  88                         thread_add_background(master, clear_something, ws, 0);
  89                         return 0;
  90                 }
  91         }
  92
  93         /* All done! */
  94         XFREE(MTYPE_TMP, ws->str);
  95         XFREE(MTYPE_TMP, ws);
  96         return 0;
  97 }
  98
  99 DEFUN (clear_foo,
 100        clear_foo_cmd,
 101        "clear foo LINE...",
 102        "clear command\n"
 103        "arbitrary string\n")
 104 {
 105         char *str;
 106         struct work_state *ws;
 107
 108         if (!argc) {
 109                 vty_out(vty, "%% string argument required%s", VTY_NEWLINE);
 110                 return CMD_WARNING;
 111         }
 112
 113         str = argv_concat(argv, argc, 0);
 114
 115         if ((ws = XMALLOC(MTYPE_TMP, sizeof(*ws))) == NULL) {
 116                 zlog_err("%s: unable to allocate work_state", __func__);
 117                 return CMD_WARNING;
 118         }
 119
 120         if (!(ws->str = XSTRDUP(MTYPE_TMP, str))) {
 121                 zlog_err("%s: unable to xstrdup", __func__);
 122                 XFREE(MTYPE_TMP, ws);
 123                 return CMD_WARNING;
 124         }
 125
 126         ws->vty = vty;
 127         ws->i = ITERS_FIRST;
 128
 129         thread_add_background(master, clear_something, ws, 0);
 130
 131         return CMD_SUCCESS;
 132 }
 133
 134 void test_init()
 135 {
 136         install_element(VIEW_NODE, &clear_foo_cmd);
 137 }