NSH: Add a time command that can be used to time other commands

ChangeLog.txt

@@ -1506,4 +1506,5 @@
 	  driver.  From Alan Carvalho de Assis (2015-12-15).
 	* apps/examples/ostest:  Add a test of POSIX timers using
 	  SIGEV_THREAD (20156-12-30).
-
+	* apps/nshlib:  Add a 'time' command that may be used to time the
+	  execution of other commands (2015-12-31).

nshlib/Kconfig

@@ -395,6 +395,11 @@ config NSH_DISABLE_SLEEP
 	bool "Disable sleep"
 	default n
 
+config NSH_DISABLE_TIME
+	bool "Disable time"
+	default y if DEFAULT_SMALL
+	default n if !DEFAULT_SMALL
+
 config NSH_DISABLE_TEST
 	bool "Disable test"
 	default n

nshlib/README.txt

@@ -1000,6 +1000,23 @@ o sleep <sec>
 
   Pause execution (sleep) of <sec> seconds.
 
+o time "<command>"
+
+  Perform command timing.  This command will execute the following <command>
+  string and then show how much time was required to execute the command.
+  Time is shown with a resolution of 100 microseconds which may be beyond
+  the resolution of many configurations.  Note that the <command> string
+  must be enclosed in quotation marks.
+
+  Example:
+
+    nsh> time "sleep 2"
+
+    2.0001 sec
+
+  The addition 100 microseconds in this example is the additional overhead
+  of the time command execution itself which is included in the total.
+
 o unset <name>
 
   Remove the value associated with the environment variable
@@ -1133,6 +1150,7 @@ Command Dependencies on Configuration Settings
   shutdown   CONFIG_BOARDCTL_POWEROFF || CONFIG_BOARDCTL_RESET
   sleep      !CONFIG_DISABLE_SIGNALS
   test       !CONFIG_NSH_DISABLESCRIPT
+  time       ---
   umount     !CONFIG_DISABLE_MOUNTPOINT && CONFIG_NFILE_DESCRIPTORS > 0 && CONFIG_FS_READABLE
   uname      !CONFIG_NSH_DISABLE_UNAME
   unset      !CONFIG_DISABLE_ENVIRON
@@ -1173,9 +1191,10 @@ also allow it to squeeze into very small memory footprints.
   CONFIG_NSH_DISABLE_PING6,     CONFIG_NSH_DISABLE_PUT,       CONFIG_NSH_DISABLE_PWD,
   CONFIG_NSH_DISABLE_REBOOT,    CONFIG_NSH_DISABLE_RM,        CONFIG_NSH_DISABLE_RMDIR,
   CONFIG_NSH_DISABLE_SET,       CONFIG_NSH_DISABLE_SH,        CONFIG_NSH_DISABLE_SHUTDOWN,
-  CONFIG_NSH_DISABLE_SLEEP,     CONFIG_NSH_DISABLE_TEST,      CONFIG_NSH_DISABLE_UMOUNT,
-  CONFIG_NSH_DISABLE_UNSET,     CONFIG_NSH_DISABLE_URLDECODE, CONFIG_NSH_DISABLE_URLENCODE,
-  CONFIG_NSH_DISABLE_USLEEP,    CONFIG_NSH_DISABLE_WGET,      CONFIG_NSH_DISABLE_XD
+  CONFIG_NSH_DISABLE_SLEEP,     CONFIG_NSH_DISABLE_TEST,      CONFIG_NSH_DIABLE_TIME,
+  CONFIG_NSH_DISABLE_UMOUNT,    CONFIG_NSH_DISABLE_UNSET,     CONFIG_NSH_DISABLE_URLDECODE,
+  CONFIG_NSH_DISABLE_URLENCODE, CONFIG_NSH_DISABLE_USLEEP,    CONFIG_NSH_DISABLE_WGET,
+  CONFIG_NSH_DISABLE_XD
 
 Verbose help output can be suppressed by defining CONFIG_NSH_HELP_TERSE.  In that
 case, the help command is still available but will be slightly smaller.

nshlib/nsh.h

@@ -934,6 +934,9 @@ void nsh_usbtrace(void);
 #ifndef CONFIG_NSH_DISABLE_FREE
   int cmd_free(FAR struct nsh_vtbl_s *vtbl, int argc, char **argv);
 #endif
+#ifndef CONFIG_NSH_DISABLE_TIME
+  int cmd_time(FAR struct nsh_vtbl_s *vtbl, int argc, char **argv);
+#endif
 #ifndef CONFIG_NSH_DISABLE_PS
   int cmd_ps(FAR struct nsh_vtbl_s *vtbl, int argc, char **argv);
 #endif

nshlib/nsh_command.c

@@ -435,6 +435,10 @@ static const struct cmdmap_s g_cmdmap[] =
   { "test",     cmd_test,     3, CONFIG_NSH_MAXARGUMENTS, "<expression>" },
 #endif
 
+#ifndef CONFIG_NSH_DISABLE_TIME
+  { "time",     cmd_time,     2, 2, "\"<command>\"" },
+#endif
+
 #ifndef CONFIG_NSH_DISABLESCRIPT
   { "true",     cmd_true,     1, 1, NULL },
 #endif

nshlib/nsh_timcmds.c

@@ -53,9 +53,11 @@
 
 #define MAX_TIME_STRING 80
 
-/****************************************************************************
- * Private Types
- ****************************************************************************/
+#ifdef CONFIG_CLOCK_MONOTONIC
+#  define TIME_CLOCK CLOCK_MONOTONIC
+#else
+#  define TIME_CLOCK CLOCK_REALTIME
+#endif
 
 /****************************************************************************
  * Private Function Prototypes
@@ -283,6 +285,67 @@ errout_bad_parm:
  * Public Functions
  ****************************************************************************/
 
+/****************************************************************************
+ * Name: cmd_time
+ ****************************************************************************/
+
+#ifndef CONFIG_NSH_DISABLE_TIME
+int cmd_time(FAR struct nsh_vtbl_s *vtbl, int argc, char **argv)
+{
+  struct timespec start;
+  bool bgsave;
+  bool redirsave;
+  int ret;
+
+  /* Get the current time */
+
+  ret = clock_gettime(TIME_CLOCK, &start);
+  if (ret < 0)
+    {
+       nsh_output(vtbl, g_fmtcmdfailed, argv[0], "clock_gettime", NSH_ERRNO);
+       return ERROR;
+    }
+
+  /* Save state */
+
+  bgsave    = vtbl->np.np_bg;
+  redirsave = vtbl->np.np_redirect;
+
+  /* Execute the command */
+
+  ret = nsh_parse(vtbl, argv[1]);
+  if (ret >= 0)
+    {
+      struct timespec end;
+      struct timespec diff;
+
+      ret = clock_gettime(TIME_CLOCK, &end);
+      if (ret < 0)
+        {
+           nsh_output(vtbl, g_fmtcmdfailed, argv[0], "clock_gettime", NSH_ERRNO);
+           ret = ERROR;
+        }
+      else
+        {
+          diff.tv_sec = end.tv_sec - start.tv_sec;
+          if (start.tv_nsec > end.tv_nsec)
+            {
+              diff.tv_sec--;
+              end.tv_nsec += 1000000000;
+            }
+
+          diff.tv_nsec = end.tv_nsec - start.tv_nsec;
+          nsh_output(vtbl, "\n%lu.%04lu sec\n", (unsigned long)diff.tv_sec,
+                     (unsigned long)diff.tv_nsec / 10000000);
+        }
+    }
+
+  vtbl->np.np_bg       = bgsave;
+  vtbl->np.np_redirect = redirsave;
+  return ret;
+}
+#endif
+
 /****************************************************************************
  * Name: cmd_date
  ****************************************************************************/