Imported Upstream version 3.2.2

[debian/gnuradio] / gruel / src / lib / realtime.cc

diff --git a/gruel/src/lib/realtime.cc b/gruel/src/lib/realtime.cc
new file mode 100644 (file)
index 0000000..7397cf3
--- /dev/null
+++ b/gruel/src/lib/realtime.cc
@@ -0,0 +1,146 @@
+/* -*- c++ -*- */
+/*
+ * Copyright 2006,2007,2008 Free Software Foundation, Inc.
+ * 
+ * This file is part of GNU Radio
+ * 
+ * GNU Radio is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 3, or (at your option)
+ * any later version.
+ * 
+ * GNU Radio is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ * 
+ * You should have received a copy of the GNU General Public License
+ * along with GNU Radio; see the file COPYING.  If not, write to
+ * the Free Software Foundation, Inc., 51 Franklin Street,
+ * Boston, MA 02110-1301, USA.
+ */
+
+#ifdef HAVE_CONFIG_H
+#include <config.h>
+#endif
+
+#include <gruel/realtime.h>
+
+#ifdef HAVE_SCHED_H
+#include <sched.h>
+#endif
+
+#include <algorithm>
+#include <math.h>
+#include <string.h>
+#include <errno.h>
+#include <stdio.h>
+
+#if defined(HAVE_PTHREAD_SETSCHEDPARAM) || defined(HAVE_SCHED_SETSCHEDULER)
+#include <pthread.h>
+
+namespace gruel {
+
+  /*!
+   * Rescale our virtual priority so that it maps to the middle 1/2 of
+   * the priorities given by min_real_pri and max_real_pri.
+   */
+  static int
+  rescale_virtual_pri(int virtual_pri, int min_real_pri, int max_real_pri)
+  {
+    float rmin = min_real_pri + (0.25 * (max_real_pri - min_real_pri));
+    float rmax = min_real_pri + (0.75 * (max_real_pri - min_real_pri));
+    float m = (rmax - rmin) / (rt_priority_max() - rt_priority_min());
+    float y = m * (virtual_pri - rt_priority_min()) + rmin;
+    int   y_int = static_cast<int>(rint(y));
+    return std::max(min_real_pri, std::min(max_real_pri, y_int));
+  }
+
+}  // namespace gruel
+
+#endif
+
+
+#if defined(HAVE_PTHREAD_SETSCHEDPARAM)
+
+namespace gruel {
+
+  rt_status_t
+  enable_realtime_scheduling(rt_sched_param p)
+  {
+    int policy = p.policy == RT_SCHED_FIFO ? SCHED_FIFO : SCHED_RR;
+    int min_real_pri = sched_get_priority_min(policy);
+    int max_real_pri = sched_get_priority_max(policy);
+    int pri = rescale_virtual_pri(p.priority, min_real_pri, max_real_pri);
+
+    // FIXME check hard and soft limits with getrlimit, and limit the value we ask for.
+    // fprintf(stderr, "pthread_setschedparam: policy = %d, pri = %d\n", policy, pri);
+
+    struct sched_param param;
+    memset (&param, 0, sizeof (param));
+    param.sched_priority = pri;
+    int result = pthread_setschedparam (pthread_self(), policy, &param);
+    if (result != 0) {
+      if (result == EPERM)     // N.B., return value, not errno
+        return RT_NO_PRIVS;
+      else {
+       fprintf(stderr,
+               "pthread_setschedparam: failed to set real time priority: %s\n",
+               strerror(result));
+        return RT_OTHER_ERROR;
+      }
+    }
+  
+    //printf("SCHED_FIFO enabled with priority = %d\n", pri);
+    return RT_OK;
+  }
+} // namespace gruel
+
+
+#elif defined(HAVE_SCHED_SETSCHEDULER)
+
+namespace gruel {
+
+  rt_status_t
+  enable_realtime_scheduling(rt_sched_param p)
+  {
+    int policy = p.policy == RT_SCHED_FIFO ? SCHED_FIFO : SCHED_RR;
+    int min_real_pri = sched_get_priority_min(policy);
+    int max_real_pri = sched_get_priority_max(policy);
+    int pri = rescale_virtual_pri(p.priority, min_real_pri, max_real_pri);
+
+    // FIXME check hard and soft limits with getrlimit, and limit the value we ask for.
+    // fprintf(stderr, "sched_setscheduler: policy = %d, pri = %d\n", policy, pri);
+
+    int pid = 0;  // this process
+    struct sched_param param;
+    memset(&param, 0, sizeof(param));
+    param.sched_priority = pri;
+    int result = sched_setscheduler(pid, policy, &param);
+    if (result != 0){
+      if (errno == EPERM)
+        return RT_NO_PRIVS;
+      else {
+        perror ("sched_setscheduler: failed to set real time priority");
+        return RT_OTHER_ERROR;
+      }
+    }
+    
+    //printf("SCHED_FIFO enabled with priority = %d\n", pri);
+    return RT_OK;
+  }
+
+} // namespace gruel
+
+#else
+
+namespace gruel {
+
+  rt_status_t
+  enable_realtime_scheduling(rt_sched_param p)
+  {
+    return RT_NOT_IMPLEMENTED;
+  }
+} // namespace gruel
+
+#endif