Add testcase for preemptions on wakeup under P-EDF and P-FP

Resuming higher-priority tasks should of course preempt lower-priority
tasks. This test case infers if higher-priority tasks are unreasonably
delayed.

3 files changed, 85 insertions, 0 deletions

diff --git a/Makefile b/Makefile
index 391dc65..4702f6e 100644
--- a/Makefile
+++ b/Makefile
@@ -185,6 +185,7 @@ vpath %.c tests/
 
 src-runtests = $(wildcard tests/*.c)
 obj-runtests = $(patsubst tests/%.c,%.o,${src-runtests})
+lib-runtests = -lrt
 
 # generate list of tests automatically
 test_catalog.inc: $(filter-out tests/runner.c,${src-runtests})
diff --git a/include/tests.h b/include/tests.h
index 79e1575..ed2b409 100644
--- a/include/tests.h
+++ b/include/tests.h
@@ -50,4 +50,6 @@ struct testsuite {
 
 #define TESTCASE(function, plugins, description) void test_ ## function (void)
 
+#define FORK_TASK(code) ({int __pid = fork(); if (__pid == 0) {code; exit(0);}; __pid;})
+
 #endif
diff --git a/tests/sched.c b/tests/sched.c
new file mode 100644
index 0000000..ab47a91
--- /dev/null
+++ b/tests/sched.c
@@ -0,0 +1,82 @@
+#include <sys/wait.h> /* for waitpid() */
+#include <unistd.h>
+#include <stdio.h>
+
+#include "tests.h"
+#include "litmus.h"
+
+TESTCASE(preempt_on_resume, P_FP | PSN_EDF,
+         "preempt lower-priority task when a higher-priority task resumes")
+{
+        int child_hi, child_lo, status, waiters;
+        lt_t delay = ms2lt(100);
+        double start, stop;
+
+        struct rt_task params;
+        params.cpu        = 0;
+        params.exec_cost  =  ms2lt(10000);
+        params.period     = ms2lt(100000);
+        params.relative_deadline = params.period;
+        params.phase      = 0;
+        params.cls        = RT_CLASS_HARD;
+        params.budget_policy = NO_ENFORCEMENT;
+
+        child_lo = FORK_TASK(
+                params.priority = LITMUS_LOWEST_PRIORITY;
+                SYSCALL( set_rt_task_param(gettid(), &params) );
+                SYSCALL( be_migrate_to(params.cpu) );
+                SYSCALL( task_mode(LITMUS_RT_TASK) );
+
+                SYSCALL( wait_for_ts_release() );
+
+                start = cputime();
+
+                while (cputime() - start < 10)
+                        ;
+
+                );
+
+        child_hi = FORK_TASK(
+                params.priority = LITMUS_HIGHEST_PRIORITY;
+                params.relative_deadline -= 1000000;
+                SYSCALL( set_rt_task_param(gettid(), &params) );
+                SYSCALL( be_migrate_to(params.cpu) );
+                SYSCALL( task_mode(LITMUS_RT_TASK) );
+
+                SYSCALL( wait_for_ts_release() );
+
+                start = cputime();
+
+                while (cputime() - start < 0.1)
+                        ;
+
+                start = wctime();
+                SYSCALL( lt_sleep(ms2lt(100)) );
+                stop = wctime();
+
+                SYSCALL( kill(child_lo, SIGUSR2) );
+
+                if (stop - start >= 0.2)
+                        fprintf(stderr, "\nHi-prio delay = %fsec\n",
+                                stop - start - (ms2lt(100) / 1E9));
+
+                /* Assert we woke up 'soonish' after the sleep. */
+                ASSERT( stop - start < 0.2 );
+                );
+
+
+        do {
+                waiters = get_nr_ts_release_waiters();
+                ASSERT( waiters >= 0 );
+        } while (waiters != 2);
+
+        waiters = release_ts(&delay);
+
+        SYSCALL( waitpid(child_hi, &status, 0) );
+        ASSERT( status == 0 );
+
+        SYSCALL( waitpid(child_lo, &status, 0) );
+        ASSERT( status ==  SIGUSR2);
+}
+
+