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
40extern struct thread_master *master;
41
42enum
43{
44  ITERS_FIRST = 0,
45  ITERS_ERR = 100,
46  ITERS_LATER = 400,
47  ITERS_PRINT = 10,
48  ITERS_MAX = 1000,
49};
50
51struct work_state {
52  struct vty *vty;
53  char *str;
54  int i;
55};
56
57static void
58slow_func (struct vty *vty, const char *str, const int i)
59{
60  double x = 1;
61  int j;
62
63  for (j = 0; j < 300; j++)
64    x += sin(x)*j;
65
66  if ((i % ITERS_LATER) == 0)
67    printf ("%s: %d, temporary error, save this somehow and do it later..\n",
68            __func__, i);
69
70  if ((i % ITERS_ERR) == 0)
71    printf ("%s: hard error\n", __func__);
72
73  if ((i % ITERS_PRINT) == 0)
74    printf ("%s did %d, x = %g\n", str, i, x);
75}
76
77static int
78clear_something (struct thread *thread)
79{
80  struct work_state *ws = THREAD_ARG(thread);
81
82  /* this could be like iterating through 150k of route_table
83   * or worse, iterating through a list of peers, to bgp_stop them with
84   * each having 150k route tables to process...
85   */
86  while (ws->i < ITERS_MAX)
87    {
88      slow_func(ws->vty, ws->str, ws->i);
89      ws->i++;
90      if (thread_should_yield(thread))
91        {
92	  thread_add_background(master, clear_something, ws, 0);
93	  return 0;
94        }
95    }
96
97  /* All done! */
98  XFREE (MTYPE_TMP, ws->str);
99  XFREE (MTYPE_TMP, ws);
100  return 0;
101}
102
103DEFUN (clear_foo,
104       clear_foo_cmd,
105       "clear foo .LINE",
106       "clear command\n"
107       "arbitrary string\n")
108{
109  char *str;
110  struct work_state *ws;
111
112  if (!argc)
113    {
114      vty_out (vty, "%% string argument required%s", VTY_NEWLINE);
115      return CMD_WARNING;
116    }
117
118  str = argv_concat (argv, argc, 0);
119
120  if ((ws = XMALLOC(MTYPE_TMP, sizeof(*ws))) == NULL)
121    {
122      zlog_err ("%s: unable to allocate work_state", __func__);
123      return CMD_WARNING;
124    }
125
126  if (!(ws->str = XSTRDUP (MTYPE_TMP, str)))
127    {
128      zlog_err ("%s: unable to xstrdup", __func__);
129      XFREE (MTYPE_TMP, ws);
130      return CMD_WARNING;
131    }
132
133  ws->vty = vty;
134  ws->i = ITERS_FIRST;
135
136  thread_add_background(master, clear_something, ws, 0);
137
138  return CMD_SUCCESS;
139}
140
141void
142test_init()
143{
144  install_element (VIEW_NODE, &clear_foo_cmd);
145}
146