[PATCH] osmo-trx[master]: Add '-t' command line option to enable SCHED_RR

[Harald Welte]

Review at  https://gerrit.osmocom.org/3080

Add '-t' command line option to enable SCHED_RR

SCHED_RR allows us to operate osmo-trx reliable even under exceptionally
high system load, as the realtime scheduler priority will have higher
priority than the other "regular" tasks on the system.

Change-Id: Ia2452b9763960b2be37fbeee9d832554da68a53f
Closes: OS#2344
---
M Transceiver52M/osmo-trx.cpp
1 file changed, 29 insertions(+), 2 deletions(-)


  git pull ssh://gerrit.osmocom.org:29418/osmo-trx refs/changes/80/3080/1

diff --git a/Transceiver52M/osmo-trx.cpp b/Transceiver52M/osmo-trx.cpp
index 31a99cf..61b3098 100644
--- a/Transceiver52M/osmo-trx.cpp
+++ b/Transceiver52M/osmo-trx.cpp
@@ -27,6 +27,7 @@
 #include <signal.h>
 #include <stdlib.h>
 #include <unistd.h>
+#include <sched.h>
 
 #include <GSMCommon.h>
 #include <Logger.h>
@@ -77,6 +78,7 @@
        double rssi_offset;
        bool swap_channels;
        bool edge;
+       int sched_rr;
 };
 
 ConfigurationTable gConfig;
@@ -259,7 +261,8 @@
                "  -r    Random Normal Burst test mode with TSC\n"
                "  -A    Random Access Burst test mode with delay\n"
                "  -R    RSSI to dBm offset in dB (default=0)\n"
-               "  -S    Swap channels (UmTRX only)\n",
+               "  -S    Swap channels (UmTRX only)\n"
+               "  -t    SCHED_RR real-time priority (1..32)\n",
                "EMERG, ALERT, CRT, ERR, WARNING, NOTICE, INFO, DEBUG");
 }
 
@@ -283,8 +286,9 @@
        config->rssi_offset = 0.0;
        config->swap_channels = false;
        config->edge = false;
+       config->sched_rr = -1;
 
-       while ((option = getopt(argc, argv, "ha:l:i:p:c:dmxgfo:s:b:r:A:R:Se")) 
!= -1) {
+       while ((option = getopt(argc, argv, 
"ha:l:i:p:c:dmxgfo:s:b:r:A:R:Set:")) != -1) {
                switch (option) {
                case 'h':
                        print_help();
@@ -343,6 +347,9 @@
                case 'e':
                        config->edge = true;
                        break;
+               case 't':
+                       config->sched_rr = atoi(optarg);
+                       break;
                default:
                        print_help();
                        exit(0);
@@ -386,6 +393,21 @@
        exit(0);
 }
 
+static int set_sched_rr(int prio)
+{
+       struct sched_param param;
+       int rc;
+       memset(&param, 0, sizeof(param));
+       param.sched_priority = prio;
+       printf("Setting SCHED_RR priority(%d)\n", param.sched_priority);
+       rc = sched_setscheduler(getpid(), SCHED_RR, &param);
+       if (rc != 0) {
+               std::cerr << "Config: Setting SCHED_RR failed" << std::endl;
+               return -1;
+       }
+       return 0;
+}
+
 int main(int argc, char *argv[])
 {
        int type, chans, ref;
@@ -424,6 +446,11 @@
 
        handle_options(argc, argv, &config);
 
+       if (config.sched_rr != -1) {
+               if (set_sched_rr(config.sched_rr) < 0)
+                       return EXIT_FAILURE;
+       }
+
        setup_signal_handlers();
 
        /* Check database sanity */

-- 
To view, visit https://gerrit.osmocom.org/3080
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Gerrit-MessageType: newchange
Gerrit-Change-Id: Ia2452b9763960b2be37fbeee9d832554da68a53f
Gerrit-PatchSet: 1
Gerrit-Project: osmo-trx
Gerrit-Branch: master
Gerrit-Owner: Harald Welte <lafo...@gnumonks.org>