core: ask RealtimeKit for RT scheduling

src/Makefile.am

@@ -573,6 +573,7 @@ libpulsecommon_@PA_MAJORMINORMICRO@_la_SOURCES = \
 		pulsecore/conf-parser.c pulsecore/conf-parser.h \
 		pulsecore/core-error.c pulsecore/core-error.h \
 		pulsecore/core-util.c pulsecore/core-util.h \
+		pulsecore/rtkit.c pulsecore/rtkit.h \
 		pulsecore/creds.h \
 		pulsecore/dynarray.c pulsecore/dynarray.h \
 		pulsecore/endianmacros.h \
@@ -1735,6 +1736,11 @@ update-reserve:
 		wget -O modules/$$i http://git.0pointer.de/\?p=reserve.git\;a=blob_plain\;f=$$i\;hb=master ; \
 	done
 
+update-rtkit:
+	for i in rtkit.c rtkit.h ; do \
+		wget -O pulsecore/$$i http://git.0pointer.de/\?p=rtkit.git\;a=blob_plain\;f=$$i\;hb=master ; \
+	done
+
 # Automatically generate linker version script. We use the same one for all public .sos
 update-map-file:
 	( echo "PULSE_0 {" ; \

src/pulsecore/core-util.c

@@ -50,6 +50,10 @@
 
 #ifdef HAVE_SCHED_H
 #include <sched.h>
+
+#if defined(__linux__) && !defined(SCHED_RESET_ON_FORK)
+#define SCHED_RESET_ON_FORK 0x40000000
+#endif
 #endif
 
 #ifdef HAVE_SYS_RESOURCE_H
@@ -92,6 +96,10 @@
 #include <xlocale.h>
 #endif
 
+#ifdef HAVE_DBUS
+#include "rtkit.h"
+#endif
+
 #include <pulse/xmalloc.h>
 #include <pulse/util.h>
 #include <pulse/utf8.h>
@@ -552,16 +560,68 @@ char *pa_strlcpy(char *b, const char *s, size_t l) {
     return b;
 }
 
+static int set_scheduler(int rtprio) {
+    struct sched_param sp;
+    int r;
+#ifdef HAVE_DBUS
+    DBusError error;
+    DBusConnection *bus;
+
+    dbus_error_init(&error);
+#endif
+
+    pa_zero(sp);
+    sp.sched_priority = rtprio;
+
+#ifdef SCHED_RESET_ON_FORK
+    if ((r = pthread_setschedparam(pthread_self(), SCHED_RR|SCHED_RESET_ON_FORK, &sp)) == 0) {
+        pa_log_debug("SCHED_RR|SCHED_RESET_ON_FORK worked.");
+        return 0;
+    }
+#endif
+
+    if ((r = pthread_setschedparam(pthread_self(), SCHED_RR, &sp)) == 0) {
+        pa_log_debug("SCHED_RR worked.");
+        return 0;
+    }
+
+#ifdef HAVE_DBUS
+    /* Try to talk to RealtimeKit */
+
+    if (!(bus = dbus_bus_get(DBUS_BUS_SYSTEM, &error))) {
+        pa_log("Failed to connect to system bus: %s\n", error.message);
+        dbus_error_free(&error);
+        errno = -EIO;
+        return -1;
+    }
+
+    r = rtkit_make_realtime(bus, 0, rtprio);
+    dbus_connection_unref(bus);
+
+    if (r >= 0) {
+        pa_log_debug("RealtimeKit worked.");
+        return 0;
+    }
+
+    errno = -r;
+#else
+    errno = r;
+#endif
+
+    return -1;
+}
+
 /* Make the current thread a realtime thread, and acquire the highest
  * rtprio we can get that is less or equal the specified parameter. If
  * the thread is already realtime, don't do anything. */
 int pa_make_realtime(int rtprio) {
 
 #ifdef _POSIX_PRIORITY_SCHEDULING
-    struct sched_param sp;
     int r, policy;
+    struct sched_param sp;
+    int rtprio_try;
 
-    memset(&sp, 0, sizeof(sp));
+    pa_zero(sp);
     policy = 0;
 
     if ((r = pthread_getschedparam(pthread_self(), &policy, &sp)) != 0) {
@@ -569,29 +629,29 @@ int pa_make_realtime(int rtprio) {
         return -1;
     }
 
-    if (policy == SCHED_FIFO && sp.sched_priority >= rtprio) {
-        pa_log_info("Thread already being scheduled with SCHED_FIFO with priority %i.", sp.sched_priority);
+#ifdef SCHED_RESET_ON_FORK
+    policy &= ~SCHED_RESET_ON_FORK;
+#endif
+
+    if ((policy == SCHED_FIFO || policy == SCHED_RR) && sp.sched_priority >= rtprio) {
+        pa_log_info("Thread already being scheduled with SCHED_FIFO/SCHED_RR with priority %i.", sp.sched_priority);
         return 0;
     }
 
-    sp.sched_priority = rtprio;
-    if ((r = pthread_setschedparam(pthread_self(), SCHED_FIFO, &sp)) != 0) {
-
-        while (sp.sched_priority > 1) {
-            sp.sched_priority --;
-
-            if ((r = pthread_setschedparam(pthread_self(), SCHED_FIFO, &sp)) == 0) {
-                pa_log_info("Successfully enabled SCHED_FIFO scheduling for thread, with priority %i, which is lower than the requested %i.", sp.sched_priority, rtprio);
-                return 0;
-            }
-        }
-
-        pa_log_warn("pthread_setschedparam(): %s", pa_cstrerror(r));
-        return -1;
+    if (set_scheduler(rtprio) >= 0) {
+        pa_log_info("Successfully enabled SCHED_RR scheduling for thread, with priority %i.", rtprio);
+        return 0;
     }
 
-    pa_log_info("Successfully enabled SCHED_FIFO scheduling for thread, with priority %i.", sp.sched_priority);
-    return 0;
+    for (rtprio_try = rtprio-1; rtprio_try >= 1; rtprio_try--) {
+        if (set_scheduler(rtprio_try)) {
+            pa_log_info("Successfully enabled SCHED_RR scheduling for thread, with priority %i, which is lower than the requested %i.", rtprio_try, rtprio);
+            return 0;
+        }
+    }
+
+    pa_log_warn("Failed to acquire real-time scheduling: %s", pa_cstrerror(r));
+    return -1;
 #else
 
     errno = ENOTSUP;

src/pulsecore/rtkit.c

@@ -0,0 +1,189 @@
+/*-*- Mode: C; c-basic-offset: 8 -*-*/
+
+/***
+  Copyright 2009 Lennart Poettering
+
+  Permission is hereby granted, free of charge, to any person
+  obtaining a copy of this software and associated documentation files
+  (the "Software"), to deal in the Software without restriction,
+  including without limitation the rights to use, copy, modify, merge,
+  publish, distribute, sublicense, and/or sell copies of the Software,
+  and to permit persons to whom the Software is furnished to do so,
+  subject to the following conditions:
+
+  The above copyright notice and this permission notice shall be
+  included in all copies or substantial portions of the Software.
+
+  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+  EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+  MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+  NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
+  BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
+  ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+  CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+  SOFTWARE.
+***/
+
+#include <errno.h>
+
+#include "rtkit.h"
+
+#ifdef __linux__
+
+#ifndef _GNU_SOURCE
+#define _GNU_SOURCE
+#endif
+
+#include <string.h>
+#include <unistd.h>
+#include <sys/types.h>
+#include <sys/syscall.h>
+
+static pid_t _gettid(void) {
+        return (pid_t) syscall(SYS_gettid);
+}
+
+static int translate_error(const char *name) {
+        if (strcmp(name, DBUS_ERROR_NO_MEMORY) == 0)
+                return -ENOMEM;
+        if (strcmp(name, DBUS_ERROR_SERVICE_UNKNOWN) == 0 ||
+            strcmp(name, DBUS_ERROR_NAME_HAS_NO_OWNER) == 0)
+                return -ENOENT;
+        if (strcmp(name, DBUS_ERROR_ACCESS_DENIED) == 0 ||
+            strcmp(name, DBUS_ERROR_AUTH_FAILED) == 0)
+                return -EACCES;
+
+        return -EIO;
+}
+
+int rtkit_make_realtime(DBusConnection *connection, pid_t thread, int priority) {
+        DBusMessage *m = NULL, *r = NULL;
+        dbus_uint64_t u64;
+        dbus_uint32_t u32;
+        DBusError error;
+        int ret;
+
+        dbus_error_init(&error);
+
+        if (thread == 0)
+                thread = _gettid();
+
+        if (!(m = dbus_message_new_method_call(
+                              RTKIT_SERVICE_NAME,
+                              RTKIT_OBJECT_PATH,
+                              "org.freedesktop.RealtimeKit1",
+                              "MakeThreadRealtime"))) {
+                ret = -ENOMEM;
+                goto finish;
+        }
+
+        u64 = (dbus_uint64_t) thread;
+        u32 = (dbus_uint32_t) priority;
+
+        if (!dbus_message_append_args(
+                            m,
+                            DBUS_TYPE_UINT64, &u64,
+                            DBUS_TYPE_UINT32, &u32,
+                            DBUS_TYPE_INVALID)) {
+                ret = -ENOMEM;
+                goto finish;
+        }
+
+        if (!(r = dbus_connection_send_with_reply_and_block(connection, m, -1, &error))) {
+                ret = translate_error(error.name);
+                goto finish;
+        }
+
+
+        if (dbus_set_error_from_message(&error, r)) {
+                ret = translate_error(error.name);
+                goto finish;
+        }
+
+        ret = 0;
+
+finish:
+
+        if (m)
+                dbus_message_unref(m);
+
+        if (r)
+                dbus_message_unref(r);
+
+        dbus_error_free(&error);
+
+        return ret;
+}
+
+int rtkit_make_high_priority(DBusConnection *connection, pid_t thread, int nice_level) {
+        DBusMessage *m = NULL, *r = NULL;
+        dbus_uint64_t u64;
+        dbus_int32_t s32;
+        DBusError error;
+        int ret;
+
+        dbus_error_init(&error);
+
+        if (thread == 0)
+                thread = _gettid();
+
+        if (!(m = dbus_message_new_method_call(
+                              RTKIT_SERVICE_NAME,
+                              RTKIT_OBJECT_PATH,
+                              "org.freedesktop.RealtimeKit1",
+                              "MakeThreadHighPriority"))) {
+                ret = -ENOMEM;
+                goto finish;
+        }
+
+        u64 = (dbus_uint64_t) thread;
+        s32 = (dbus_int32_t) nice_level;
+
+        if (!dbus_message_append_args(
+                            m,
+                            DBUS_TYPE_UINT64, &u64,
+                            DBUS_TYPE_INT32, &s32,
+                            DBUS_TYPE_INVALID)) {
+                ret = -ENOMEM;
+                goto finish;
+        }
+
+
+
+        if (!(r = dbus_connection_send_with_reply_and_block(connection, m, -1, &error))) {
+                ret = translate_error(error.name);
+                goto finish;
+        }
+
+
+        if (dbus_set_error_from_message(&error, r)) {
+                ret = translate_error(error.name);
+                goto finish;
+        }
+
+        ret = 0;
+
+finish:
+
+        if (m)
+                dbus_message_unref(m);
+
+        if (r)
+                dbus_message_unref(r);
+
+        dbus_error_free(&error);
+
+        return ret;
+}
+
+#else
+
+int rtkit_make_realtime(DBusConnection *connection, pid_t thread, int priority) {
+        return -ENOTSUP;
+}
+
+int rtkit_make_high_priority(DBusConnection *connection, pid_t thread, int nice_level) {
+        return -ENOTSUP;
+}
+
+#endif

src/pulsecore/rtkit.h

@@ -0,0 +1,62 @@
+/*-*- Mode: C; c-basic-offset: 8 -*-*/
+
+#ifndef foortkithfoo
+#define foortkithfoo
+
+/***
+  Copyright 2009 Lennart Poettering
+
+  Permission is hereby granted, free of charge, to any person
+  obtaining a copy of this software and associated documentation files
+  (the "Software"), to deal in the Software without restriction,
+  including without limitation the rights to use, copy, modify, merge,
+  publish, distribute, sublicense, and/or sell copies of the Software,
+  and to permit persons to whom the Software is furnished to do so,
+  subject to the following conditions:
+
+  The above copyright notice and this permission notice shall be
+  included in all copies or substantial portions of the Software.
+
+  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+  EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+  MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+  NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
+  BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
+  ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+  CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+  SOFTWARE.
+***/
+
+#include <sys/types.h>
+#include <dbus/dbus.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/* This is the reference implementation for a client for
+ * RealtimeKit. You don't have to use this, but if do, just copy these
+ * sources into your repository */
+
+#define RTKIT_SERVICE_NAME "org.freedesktop.RealtimeKit1"
+#define RTKIT_OBJECT_PATH "/org/freedesktop/RealtimeKit1"
+
+/* This is mostly equivalent to sched_setparam(thread, SCHED_RR, {
+ * .sched_priority = priority }). 'thread' needs to be a kernel thread
+ * id as returned by gettid(), not a pthread_t! If 'thread' is 0 the
+ * current thread is used. The returned value is a negative errno
+ * style error code, or 0 on success. */
+int rtkit_make_realtime(DBusConnection *system_bus, pid_t thread, int priority);
+
+/* This is mostly equivalent to setpriority(PRIO_PROCESS, thread,
+ * nice_level). 'thread' needs to be a kernel thread id as returned by
+ * gettid(), not a pthread_t! If 'thread' is 0 the current thread is
+ * used. The returned value is a negative errno style error code, or 0
+ * on success.*/
+int rtkit_make_high_priority(DBusConnection *system_bus, pid_t thread, int nice_level);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif