[LTP] [Draft PATCH] lib: add TST_DYNAMICAL_RUNTIME option

[Li Wang <liwang@redhat.com>]

Hi, this is a draft patch to reflect the method came up in the thread,
if people agree I will polish it and send a complete one later.

Signed-off-by: Li Wang <liwang@redhat.com>
---
 include/tst_kconfig.h | 44 +++++++++++++++++++++++++++++++++++++++++++
 include/tst_test.h    |  1 +
 include/tst_timer.h   | 30 +++++++++++++++++++++++++++++
 lib/tst_test.c        | 12 ++++++++----
 4 files changed, 83 insertions(+), 4 deletions(-)

diff --git a/include/tst_kconfig.h b/include/tst_kconfig.h
index 23f807409..8f5bc06a7 100644
--- a/include/tst_kconfig.h
+++ b/include/tst_kconfig.h
@@ -98,4 +98,48 @@ struct tst_kcmdline_var {
  */
 void tst_kcmdline_parse(struct tst_kcmdline_var params[], size_t params_len);
 
+/*
+ * List of debug-related kernel config options that may degrade performance when enabled.
+ */
+static const char * const tst_kconf_debug_options[][2] = {
+	/* Lock debugging */
+	{"CONFIG_PROVE_LOCKING=y", NULL},
+	{"CONFIG_LOCKDEP=y", NULL},
+	{"CONFIG_DEBUG_SPINLOCK=y", NULL},
+
+	/* Mutexes debugging */
+	{"CONFIG_DEBUG_RT_MUTEXES=y", NULL},
+	{"CONFIG_DEBUG_MUTEXES=y", NULL},
+
+	/* Memory debugging */
+	{"CONFIG_DEBUG_PAGEALLOC=y", NULL},
+	{"CONFIG_KASAN=y", NULL},
+	{"CONFIG_SLUB_RCU_DEBUG=y", NULL},
+
+	/* Tracing and profiling */
+	{"CONFIG_TRACE_IRQFLAGS=y", NULL},
+	{"CONFIG_LATENCYTOP=y", NULL},
+	{"CONFIG_DEBUG_NET=y", NULL},
+
+	/* Filesystem debugging */
+	{"CONFIG_EXT4_DEBUG=y", NULL},
+	{"CONFIG_QUOTA_DEBUG=y", NULL},
+
+	/* Miscellaneous debugging */
+	{"CONFIG_FAULT_INJECTION=y", NULL},
+	{"CONFIG_DEBUG_OBJECTS=y", NULL},
+
+	{NULL, NULL} /* End of the array */
+};
+
+static inline int tst_kconfig_debug_matches(void)
+{
+	int i, num = 1;
+
+	for (i = 0; tst_kconf_debug_options[i][0] != NULL; i++)
+		num += tst_kconfig_check(tst_kconf_debug_options[i]);
+
+	return num;
+}
+
 #endif	/* TST_KCONFIG_H__ */
diff --git a/include/tst_test.h b/include/tst_test.h
index 8d1819f74..483b707d3 100644
--- a/include/tst_test.h
+++ b/include/tst_test.h
@@ -235,6 +235,7 @@ struct tst_tag {
 extern unsigned int tst_variant;
 
 #define TST_UNLIMITED_RUNTIME (-1)
+#define TST_DYNAMICAL_RUNTIME (-2)
 
 /**
  * struct tst_ulimit_val - An ulimit resource and value.
diff --git a/include/tst_timer.h b/include/tst_timer.h
index 6fb940020..268fc8389 100644
--- a/include/tst_timer.h
+++ b/include/tst_timer.h
@@ -17,6 +17,7 @@
 #include <mqueue.h>
 #include <time.h>
 #include "tst_test.h"
+#include "tst_clocks.h"
 #include "lapi/common_timers.h"
 #include "lapi/posix_types.h"
 #include "lapi/syscalls.h"
@@ -1074,4 +1075,33 @@ static inline long long tst_timer_elapsed_us(void)
 	return tst_timespec_to_us(tst_timer_elapsed());
 }
 
+#define CALLIBRATE_LOOPS 120000000
+
+/*
+ * Measures the time taken by the CPU to perform a specified
+ * number of empty loops for calibration.
+ */
+static inline int tst_callibrate(void)
+{
+	int i;
+	struct timespec start, stop;
+	long long diff;
+
+	for (i = 0; i < CALLIBRATE_LOOPS; i++)
+		__asm__ __volatile__ ("" : "+g" (i) : :);
+
+	tst_clock_gettime(CLOCK_MONOTONIC_RAW, &start);
+
+	for (i = 0; i < CALLIBRATE_LOOPS; i++)
+		__asm__ __volatile__ ("" : "+g" (i) : :);
+
+	tst_clock_gettime(CLOCK_MONOTONIC_RAW, &stop);
+
+	diff = tst_timespec_diff_us(stop, start);
+
+	tst_res(TINFO, "CPU did %i loops in %llius", CALLIBRATE_LOOPS, diff);
+
+	return diff;
+}
+
 #endif /* TST_TIMER */
diff --git a/lib/tst_test.c b/lib/tst_test.c
index 8db554dea..8a4460944 100644
--- a/lib/tst_test.c
+++ b/lib/tst_test.c
@@ -1265,8 +1265,8 @@ static void do_setup(int argc, char *argv[])
 	if (!tst_test)
 		tst_brk(TBROK, "No tests to run");
 
-	if (tst_test->max_runtime < -1) {
-		tst_brk(TBROK, "Invalid runtime value %i",
+	if (tst_test->max_runtime < -2) {
+		tst_brk(TBROK, "Invalid runtime value %d",
 			results->max_runtime);
 	}
 
@@ -1695,7 +1695,6 @@ unsigned int tst_remaining_runtime(void)
 	return 0;
 }
 
-
 unsigned int tst_multiply_timeout(unsigned int timeout)
 {
 	parse_mul(&timeout_mul, "LTP_TIMEOUT_MUL", 0.099, 10000);
@@ -1715,8 +1714,13 @@ static void set_timeout(void)
 		return;
 	}
 
+	if (results->max_runtime == TST_DYNAMICAL_RUNTIME) {
+		tst_res(TINFO, "Timeout is decited in running time");
+		results->max_runtime = (tst_callibrate() / 1000) * tst_kconfig_debug_matches();
+	}
+
 	if (results->max_runtime < 0) {
-		tst_brk(TBROK, "max_runtime must to be >= -1! (%d)",
+		tst_brk(TBROK, "max_runtime must to be >= -2! (%d)",
 			results->max_runtime);
 	}
 
-- 
2.47.0


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