uhd: added ability to boost rt priority, added general app notes

2 files changed, 61 insertions, 0 deletions

diff --git a/host/lib/CMakeLists.txt b/host/lib/CMakeLists.txt
index 7b765b0d3..50787f6a2 100644
--- a/host/lib/CMakeLists.txt
+++ b/host/lib/CMakeLists.txt
@@ -74,6 +74,21 @@ INCLUDE(${CMAKE_CURRENT_SOURCE_DIR}/usrp/dboard/CMakeLists.txt)
 INCLUDE(${CMAKE_CURRENT_SOURCE_DIR}/usrp/usrp2/CMakeLists.txt)
 
 ########################################################################
+# Setup defines for process scheduling
+########################################################################
+MESSAGE(STATUS "Configuring process scheduling...")
+
+INCLUDE(CheckIncludeFileCXX)
+CHECK_INCLUDE_FILE_CXX(sched.h HAVE_SCHED_H)
+
+IF(HAVE_SCHED_H)
+    MESSAGE(STATUS "  Process scheduling supported through sched_setscheduler.")
+    ADD_DEFINITIONS(-DHAVE_SCHED_H)
+ELSE(HAVE_SCHED_H)
+    MESSAGE(STATUS "  Process scheduling not supported.")
+ENDIF(HAVE_SCHED_H)
+
+########################################################################
 # Setup defines for module loading
 ########################################################################
 MESSAGE(STATUS "Configuring module loading...")
@@ -99,6 +114,7 @@ LIBUHD_APPEND_SOURCES(
     ${CMAKE_CURRENT_SOURCE_DIR}/device.cpp
     ${CMAKE_CURRENT_SOURCE_DIR}/gain_handler.cpp
     ${CMAKE_CURRENT_SOURCE_DIR}/load_modules.cpp
+    ${CMAKE_CURRENT_SOURCE_DIR}/sched.cpp
     ${CMAKE_CURRENT_SOURCE_DIR}/types.cpp
     ${CMAKE_CURRENT_SOURCE_DIR}/utils.cpp
     ${CMAKE_CURRENT_SOURCE_DIR}/wax.cpp
diff --git a/host/lib/sched.cpp b/host/lib/sched.cpp
new file mode 100644
index 000000000..712014c9c
--- /dev/null
+++ b/host/lib/sched.cpp
@@ -0,0 +1,45 @@
+//
+// Copyright 2010 Ettus Research LLC
+//
+// 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, either version 3 of the License, or
+// (at your option) any later version.
+//
+// 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://www.gnu.org/licenses/>.
+//
+
+#include <uhd/utils/static.hpp>
+#include <stdexcept>
+#include <iostream>
+
+#ifdef HAVE_SCHED_H
+#include <sched.h>
+
+/*
+ * # /etc/security/limits.conf
+#
+@usrp   -       rtprio  99
+*/
+
+UHD_STATIC_BLOCK(setup_process_sched){
+    try{
+        int policy = SCHED_RR;
+        int max_pri = sched_get_priority_max(policy);
+        if (max_pri == -1) throw std::runtime_error("sched_get_priority_max with SCHED_RR failed");
+        sched_param sp; sp.sched_priority = max_pri;
+        int ss_ret = sched_setscheduler(0, policy, &sp);
+        if (ss_ret == -1) throw std::runtime_error("sched_setscheduler with SCHED_RR failed");
+    }
+    catch(const std::exception &e){
+        std::cerr << "Process scheduling error: " << e.what() << std::endl;
+    }
+}
+
+#endif /* HAVE_SCHED_H */