update

matrix/lib/thread.cc

@@ -0,0 +1,100 @@
+// -*- mode: c++; c-basic-offset: 2; indent-tabs-mode: nil; -*-
+// Copyright (C) 2013 Henner Zeller <h.zeller@acm.org>
+//
+// This program 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 version 2.
+//
+// This program 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 this program.  If not, see <http://gnu.org/licenses/gpl-2.0.txt>
+
+#include "thread.h"
+
+#include <assert.h>
+#include <limits.h>
+#include <sched.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+namespace rgb_matrix {
+void *Thread::PthreadCallRun(void *tobject) {
+  reinterpret_cast<Thread*>(tobject)->Run();
+  return NULL;
+}
+
+Thread::Thread() : started_(false) {}
+Thread::~Thread() {
+  WaitStopped();
+}
+
+void Thread::WaitStopped() {
+  if (!started_) return;
+  int result = pthread_join(thread_, NULL);
+  if (result != 0) {
+    perror("Issue joining thread");
+  }
+  started_ = false;
+}
+
+void Thread::Start(int priority, uint32_t affinity_mask) {
+  assert(!started_);  // Did you call WaitStopped() ?
+  pthread_create(&thread_, NULL, &PthreadCallRun, this);
+  int err;
+
+  if (priority > 0) {
+    struct sched_param p;
+    p.sched_priority = priority;
+    if ((err = pthread_setschedparam(thread_, SCHED_FIFO, &p))) {
+      char buffer[PATH_MAX];
+      const char *bin = realpath("/proc/self/exe", buffer);  // Linux specific.
+      fprintf(stderr, "Can't set realtime thread priority=%d: %s.\n"
+              "\tYou are probably not running as root ?\n"
+              "\tThis will seriously mess with color stability and flicker\n"
+              "\tof the matrix. Please run as `root` (e.g. by invoking this\n"
+              "\tprogram with `sudo`), or setting the capability on this\n"
+              "\tbinary by calling\n"
+              "\tsudo setcap 'cap_sys_nice=eip' %s\n",
+              p.sched_priority, strerror(err), bin ? bin : "<this binary>");
+    }
+  }
+
+  if (affinity_mask != 0) {
+    cpu_set_t cpu_mask;
+    CPU_ZERO(&cpu_mask);
+    for (int i = 0; i < 32; ++i) {
+      if ((affinity_mask & (1<<i)) != 0) {
+        CPU_SET(i, &cpu_mask);
+      }
+    }
+    if ((err=pthread_setaffinity_np(thread_, sizeof(cpu_mask), &cpu_mask))) {
+      // On a Pi1, this won't work as there is only one core. Don't worry in
+      // that case.
+    }
+  }
+
+  started_ = true;
+}
+
+bool Mutex::WaitOn(pthread_cond_t *cond, long timeout_ms) {
+  if (timeout_ms < 0) {
+    pthread_cond_wait(cond, &mutex_);
+    return true;
+  }
+  else {
+    struct timespec t;
+    clock_gettime(CLOCK_REALTIME, &t);
+    t.tv_sec += timeout_ms / 1000;
+    t.tv_nsec += (timeout_ms % 1000) * 1000000;
+    t.tv_sec += t.tv_nsec / 1000000000;
+    t.tv_nsec %= 1000000000;
+    // TODO(hzeller): It doesn't seem we return with EINTR on signal. We should.
+    return pthread_cond_timedwait(cond, &mutex_, &t) == 0;
+  }
+}
+}  // namespace rgb_matrix