Make high pri time thread configurable

Former-commit-id: 7e94207765d2166f46792aea0919786f3f30d7b3

src/config.cpp

@@ -2535,6 +2535,7 @@ standardConfig configs[] = {
     createBoolConfig("use-fork", NULL, IMMUTABLE_CONFIG, cserver.fForkBgSave, 0, NULL, NULL),
     createBoolConfig("allow-write-during-load", NULL, MODIFIABLE_CONFIG, g_pserver->fWriteDuringActiveLoad, 0, NULL, NULL),
     createBoolConfig("io-threads-do-reads", NULL, IMMUTABLE_CONFIG, fDummy, 0, NULL, NULL),
+    createBoolConfig("time-thread-priority", NULL, IMMUTABLE_CONFIG, cserver.time_thread_priority, 0, NULL, NULL),
 
     /* String Configs */
     createStringConfig("aclfile", NULL, IMMUTABLE_CONFIG, ALLOW_EMPTY_STRING, g_pserver->acl_filename, "", NULL, NULL),

src/server.cpp

@@ -6443,9 +6443,11 @@ int main(int argc, char **argv) {
     serverAssert(cserver.cthreads > 0 && cserver.cthreads <= MAX_EVENT_LOOPS);
 
     pthread_create(&cserver.time_thread_id, nullptr, timeThreadMain, nullptr);
+if (cserver.time_thread_priority) {
     struct sched_param time_thread_priority;
     time_thread_priority.sched_priority = sched_get_priority_max(SCHED_FIFO);
     pthread_setschedparam(cserver.time_thread_id, SCHED_FIFO, &time_thread_priority);
+}
 
     pthread_attr_t tattr;
     pthread_attr_init(&tattr);

src/server.h

@@ -2000,6 +2000,7 @@ struct redisServerConst {
     int storage_memory_model = STORAGE_WRITETHROUGH;
     char *storage_conf = nullptr;
     int fForkBgSave = false;
+    int time_thread_priority = false;
 };
 
 struct redisServer {

tests/unit/introspection.tcl

@@ -90,6 +90,7 @@ start_server {tags {"introspection"}} {
             server_cpulist
             bio_cpulist
             aof_rewrite_cpulist
+            time-thread-priority
             bgsave_cpulist
 	        storage-cache-mode
 	        storage-provider-options