syscalls: Add timer measurement library

This commit adds a timer measurement library, mostly based on changes
done to the pselect01.c test and changes all tests that measure timer
precision to use it.

The timer testcases that measure timeouts now just define sampling function and
optional setup and cleanup. The rest of the functionality is implemented in the
lib/tst_timer_test.c library. This change not only removes fair amount of
duplicated code but also allows us to tune thresholds and define testcases in a
single place for all testcases.

The timer measurement library also supports for passing sleep time and
number of iterations as a command-line parameters, can print nifty
frequency plot into the terminal, as well as save test measurements into
a text file.

Signed-off-by: Cyril Hrubis <[email protected]>
Acked-by: Jan Stancek <[email protected]>

Author: metan-ucw

include/tst_test.h

@@ -145,6 +145,9 @@ struct tst_test {
 	void (*test)(unsigned int test_nr);
 	void (*test_all)(void);
 
+	/* Sampling function for timer measurement testcases */
+	int (*sample)(int clk_id, long long usec);
+
 	/* NULL terminated array of resource file names */
 	const char *const *resource_files;
 };
@@ -179,12 +182,12 @@ extern int TEST_ERRNO;
 const char *tst_strerrno(int err);
 const char *tst_strsig(int sig);
 
+void tst_set_timeout(unsigned int timeout);
+
 #ifndef TST_NO_DEFAULT_MAIN
 
 static struct tst_test test;
 
-void tst_set_timeout(unsigned int timeout);
-
 int main(int argc, char *argv[])
 {
 	tst_run_tcases(argc, argv, &test);

include/tst_timer.h

@@ -92,6 +92,32 @@ static inline struct timeval tst_us_to_timeval(long long us)
 	return ret;
 }
 
+/*
+ * Converts ms to struct timespec
+ */
+static inline struct timespec tst_ms_to_timespec(long long us)
+{
+	struct timespec ret;
+
+	ret.tv_sec = us / 1000;
+	ret.tv_nsec = (us % 1000) * 1000000;
+
+	return ret;
+}
+
+/*
+ * Converts us to struct timespec
+ */
+static inline struct timespec tst_us_to_timespec(long long us)
+{
+	struct timespec ret;
+
+	ret.tv_sec = us / 1000000;
+	ret.tv_nsec = (us % 1000000) * 1000;
+
+	return ret;
+}
+
 /*
  * Comparsions
  */

include/tst_timer_test.h

@@ -0,0 +1,57 @@
+/*
+ * Copyright (c) 2017 Cyril Hrubis <[email protected]>
+ *
+ * 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 2 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/>.
+ */
+
+ /*
+
+    Timer measuring library.
+
+    The test is supposed to define sampling function and set it in the tst_test
+    structure the rest of the work is then done by the library.
+
+    int sample(int clk_id, long long usec)
+    {
+	// Any setup done here
+
+	tst_timer_start(clk_id);
+	// Call that is being measured sleeps for usec
+	tst_timer_stop();
+	tst_timer_sample();
+
+	// Any cleanup done here
+
+	// Non-zero return exits the test
+    }
+
+    struct tst_test test = {
+	.tid = "syscall_name()",
+	.sample = sample,
+    };
+
+  */
+
+#ifndef TST_TIMER_TEST__
+#define TST_TIMER_TEST__
+
+#include "tst_test.h"
+#include "tst_timer.h"
+
+void tst_timer_sample(void);
+
+# ifdef TST_NO_DEFAULT_MAIN
+struct tst_test *tst_timer_test_setup(struct tst_test *test);
+# endif /* TST_NO_DEFAULT_MAIN */
+#endif /* TST_TIMER_TEST__ */

lib/tst_test.c

@@ -30,6 +30,7 @@
 #include "tst_device.h"
 #include "lapi/futex.h"
 #include "tst_ansi_color.h"
+#include "tst_timer_test.h"
 
 #include "old_resource.h"
 #include "old_device.h"
@@ -635,25 +636,44 @@ static const char *get_tid(char *argv[])
 static struct tst_device tdev;
 struct tst_device *tst_device;
 
-static void do_setup(int argc, char *argv[])
+static void assert_test_fn(void)
 {
-	if (!tst_test)
-		tst_brk(TBROK, "No tests to run");
+	int cnt = 0;
 
-	if (!tst_test->tid)
-		tst_test->tid = get_tid(argv);
+	if (tst_test->test)
+		cnt++;
 
-	if (!tst_test->test && !tst_test->test_all)
+	if (tst_test->test_all)
+		cnt++;
+
+	if (tst_test->sample)
+		cnt++;
+
+	if (!cnt)
 		tst_brk(TBROK, "No test function speficied");
 
-	if (tst_test->test && tst_test->test_all)
-		tst_brk(TBROK, "You can define either test() or test_all()");
+	if (cnt != 1)
+		tst_brk(TBROK, "You can define only one test function");
 
 	if (tst_test->test && !tst_test->tcnt)
 		tst_brk(TBROK, "Number of tests (tcnt) must not be > 0");
 
-	if (tst_test->test_all && tst_test->tcnt)
-		tst_brk(TBROK, "You can't define tcnt for test_all()");
+	if (!tst_test->test && tst_test->tcnt)
+		tst_brk(TBROK, "You can define tcnt only for test()");
+}
+
+static void do_setup(int argc, char *argv[])
+{
+	if (!tst_test)
+		tst_brk(TBROK, "No tests to run");
+
+	assert_test_fn();
+
+	if (tst_test->sample)
+		tst_test = tst_timer_test_setup(tst_test);
+
+	if (!tst_test->tid)
+		tst_test->tid = get_tid(argv);
 
 	if (tst_test->needs_root && geteuid() != 0)
 		tst_brk(TCONF, "Test needs to be run as root");