[dpdk-dev] [PATCH v10 2/3] eal: deduplicate timer functions

[Thomas Monjalon <thomas.monjalon@6wind.com>]

From: Ravi Kerur <rkerur@gmail.com>

Move common functions from BSD/Linux to eal_common_timer.c.
BSD uses sysctl and Linux uses CLOCK_MONOTIC_RAW to calibrate TSC.
HPET is specific to Linux and not integrated in the common init.

Signed-off-by: Ravi Kerur <rkerur@gmail.com>
Signed-off-by: Thomas Monjalon <thomas.monjalon@6wind.com>
---
 lib/librte_eal/bsdapp/eal/Makefile                 |  1 +
 lib/librte_eal/bsdapp/eal/eal_timer.c              | 58 ++--------------
 .../eal/eal_timer.c => common/eal_common_timer.c}  | 79 +++-------------------
 lib/librte_eal/common/eal_private.h                | 14 ++++
 lib/librte_eal/linuxapp/eal/Makefile               |  1 +
 lib/librte_eal/linuxapp/eal/eal_timer.c            | 60 ++--------------
 6 files changed, 39 insertions(+), 174 deletions(-)
 copy lib/librte_eal/{bsdapp/eal/eal_timer.c => common/eal_common_timer.c} (57%)

diff --git a/lib/librte_eal/bsdapp/eal/Makefile b/lib/librte_eal/bsdapp/eal/Makefile
index 24733ae..a969435 100644
--- a/lib/librte_eal/bsdapp/eal/Makefile
+++ b/lib/librte_eal/bsdapp/eal/Makefile
@@ -61,6 +61,7 @@ SRCS-$(CONFIG_RTE_LIBRTE_EAL_BSDAPP) += eal_alarm.c
 
 # from common dir
 SRCS-$(CONFIG_RTE_LIBRTE_EAL_BSDAPP) += eal_common_lcore.c
+SRCS-$(CONFIG_RTE_LIBRTE_EAL_BSDAPP) += eal_common_timer.c
 SRCS-$(CONFIG_RTE_LIBRTE_EAL_BSDAPP) += eal_common_memzone.c
 SRCS-$(CONFIG_RTE_LIBRTE_EAL_BSDAPP) += eal_common_log.c
 SRCS-$(CONFIG_RTE_LIBRTE_EAL_BSDAPP) += eal_common_launch.c
diff --git a/lib/librte_eal/bsdapp/eal/eal_timer.c b/lib/librte_eal/bsdapp/eal/eal_timer.c
index 7147abe..f12d9bd 100644
--- a/lib/librte_eal/bsdapp/eal/eal_timer.c
+++ b/lib/librte_eal/bsdapp/eal/eal_timer.c
@@ -55,29 +55,12 @@
 
 enum timer_source eal_timer_source = EAL_TIMER_TSC;
 
-/* The frequency of the RDTSC timer resolution */
-static uint64_t eal_tsc_resolution_hz = 0;
-
-void
-rte_delay_us(unsigned us)
-{
-	const uint64_t start = rte_get_timer_cycles();
-	const uint64_t ticks = (uint64_t)us * rte_get_timer_hz() / 1E6;
-	while ((rte_get_timer_cycles() - start) < ticks)
-		rte_pause();
-}
-
 uint64_t
-rte_get_tsc_hz(void)
-{
-	return eal_tsc_resolution_hz;
-}
-
-static int
-set_tsc_freq_from_sysctl(void)
+get_tsc_freq(void)
 {
 	size_t sz;
 	int tmp;
+	uint64_t tsc_hz;
 
 	sz = sizeof(tmp);
 	tmp = 0;
@@ -94,42 +77,13 @@ set_tsc_freq_from_sysctl(void)
 	else if (tmp != 1)
 		RTE_LOG(WARNING, EAL, "TSC is not invariant\n");
 
-	sz = sizeof(eal_tsc_resolution_hz);
-	if (sysctlbyname("machdep.tsc_freq", &eal_tsc_resolution_hz, &sz, NULL, 0)) {
+	sz = sizeof(tsc_hz);
+	if (sysctlbyname("machdep.tsc_freq", &tsc_hz, &sz, NULL, 0)) {
 		RTE_LOG(WARNING, EAL, "%s\n", strerror(errno));
-		return -1;
+		return 0;
 	}
 
-	return 0;
-}
-
-static void
-set_tsc_freq_fallback(void)
-{
-	RTE_LOG(WARNING, EAL, "WARNING: clock_gettime cannot use "
-			"CLOCK_MONOTONIC_RAW and HPET is not available"
-			" - clock timings may be less accurate.\n");
-	/* assume that the sleep(1) will sleep for 1 second */
-	uint64_t start = rte_rdtsc();
-	sleep(1);
-	eal_tsc_resolution_hz = rte_rdtsc() - start;
-}
-
-/*
- * This function measures the TSC frequency. It uses a variety of approaches.
- *
- * 1. Read the TSC frequency value provided by the kernel
- * 2. If above does not work, just sleep for 1 second and tune off that,
- *    printing a warning about inaccuracy of timing
- */
-static void
-set_tsc_freq(void)
-{
-	if (set_tsc_freq_from_sysctl() < 0)
-		set_tsc_freq_fallback();
-
-	RTE_LOG(INFO, EAL, "TSC frequency is ~%"PRIu64" KHz\n",
-			eal_tsc_resolution_hz/1000);
+	return tsc_hz;
 }
 
 int
diff --git a/lib/librte_eal/bsdapp/eal/eal_timer.c b/lib/librte_eal/common/eal_common_timer.c
similarity index 57%
copy from lib/librte_eal/bsdapp/eal/eal_timer.c
copy to lib/librte_eal/common/eal_common_timer.c
index 7147abe..2956703 100644
--- a/lib/librte_eal/bsdapp/eal/eal_timer.c
+++ b/lib/librte_eal/common/eal_common_timer.c
@@ -30,6 +30,7 @@
  *   (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  *   OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
+
 #include <string.h>
 #include <stdio.h>
 #include <unistd.h>
@@ -41,22 +42,11 @@
 #include <rte_common.h>
 #include <rte_log.h>
 #include <rte_cycles.h>
-#include <rte_memory.h>
-#include <rte_memzone.h>
-#include <rte_eal.h>
-#include <rte_debug.h>
 
 #include "eal_private.h"
-#include "eal_internal_cfg.h"
-
-#ifdef RTE_LIBEAL_USE_HPET
-#warning HPET is not supported in FreeBSD
-#endif
-
-enum timer_source eal_timer_source = EAL_TIMER_TSC;
 
 /* The frequency of the RDTSC timer resolution */
-static uint64_t eal_tsc_resolution_hz = 0;
+static uint64_t eal_tsc_resolution_hz;
 
 void
 rte_delay_us(unsigned us)
@@ -73,68 +63,21 @@ rte_get_tsc_hz(void)
 	return eal_tsc_resolution_hz;
 }
 
-static int
-set_tsc_freq_from_sysctl(void)
+static uint64_t
+estimate_tsc_freq(void)
 {
-	size_t sz;
-	int tmp;
-
-	sz = sizeof(tmp);
-	tmp = 0;
-
-	if (sysctlbyname("kern.timecounter.smp_tsc", &tmp, &sz, NULL, 0))
-		RTE_LOG(WARNING, EAL, "%s\n", strerror(errno));
-	else if (tmp != 1)
-		RTE_LOG(WARNING, EAL, "TSC is not safe to use in SMP mode\n");
-
-	tmp = 0;
-
-	if (sysctlbyname("kern.timecounter.invariant_tsc", &tmp, &sz, NULL, 0))
-		RTE_LOG(WARNING, EAL, "%s\n", strerror(errno));
-	else if (tmp != 1)
-		RTE_LOG(WARNING, EAL, "TSC is not invariant\n");
-
-	sz = sizeof(eal_tsc_resolution_hz);
-	if (sysctlbyname("machdep.tsc_freq", &eal_tsc_resolution_hz, &sz, NULL, 0)) {
-		RTE_LOG(WARNING, EAL, "%s\n", strerror(errno));
-		return -1;
-	}
-
-	return 0;
-}
-
-static void
-set_tsc_freq_fallback(void)
-{
-	RTE_LOG(WARNING, EAL, "WARNING: clock_gettime cannot use "
-			"CLOCK_MONOTONIC_RAW and HPET is not available"
-			" - clock timings may be less accurate.\n");
+	RTE_LOG(WARNING, EAL, "WARNING: TSC frequency estimated roughly"
+		" - clock timings may be less accurate.\n");
 	/* assume that the sleep(1) will sleep for 1 second */
 	uint64_t start = rte_rdtsc();
 	sleep(1);
-	eal_tsc_resolution_hz = rte_rdtsc() - start;
+	return rte_rdtsc() - start;
 }
 
-/*
- * This function measures the TSC frequency. It uses a variety of approaches.
- *
- * 1. Read the TSC frequency value provided by the kernel
- * 2. If above does not work, just sleep for 1 second and tune off that,
- *    printing a warning about inaccuracy of timing
- */
-static void
+void
 set_tsc_freq(void)
 {
-	if (set_tsc_freq_from_sysctl() < 0)
-		set_tsc_freq_fallback();
-
-	RTE_LOG(INFO, EAL, "TSC frequency is ~%"PRIu64" KHz\n",
-			eal_tsc_resolution_hz/1000);
-}
-
-int
-rte_eal_timer_init(void)
-{
-	set_tsc_freq();
-	return 0;
+	uint64_t freq = get_tsc_freq() || estimate_tsc_freq();
+	RTE_LOG(INFO, EAL, "TSC frequency is ~%" PRIu64 " KHz\n", freq / 1000);
+	eal_tsc_resolution_hz = freq;
 }
diff --git a/lib/librte_eal/common/eal_private.h b/lib/librte_eal/common/eal_private.h
index 8505b05..f8e8869 100644
--- a/lib/librte_eal/common/eal_private.h
+++ b/lib/librte_eal/common/eal_private.h
@@ -314,4 +314,18 @@ unsigned eal_cpu_core_id(unsigned lcore_id);
  */
 int eal_cpu_detected(unsigned lcore_id);
 
+/**
+ * Set TSC frequency from precise value or estimation
+ *
+ * This function is private to the EAL.
+ */
+void set_tsc_freq(void);
+
+/**
+ * Get precise TSC frequency from system
+ *
+ * This function is private to the EAL.
+ */
+uint64_t get_tsc_freq(void);
+
 #endif /* _EAL_PRIVATE_H_ */
diff --git a/lib/librte_eal/linuxapp/eal/Makefile b/lib/librte_eal/linuxapp/eal/Makefile
index f4f8cdf..376d275 100644
--- a/lib/librte_eal/linuxapp/eal/Makefile
+++ b/lib/librte_eal/linuxapp/eal/Makefile
@@ -71,6 +71,7 @@ endif
 
 # from common dir
 SRCS-$(CONFIG_RTE_LIBRTE_EAL_LINUXAPP) += eal_common_lcore.c
+SRCS-$(CONFIG_RTE_LIBRTE_EAL_LINUXAPP) += eal_common_timer.c
 SRCS-$(CONFIG_RTE_LIBRTE_EAL_LINUXAPP) += eal_common_memzone.c
 SRCS-$(CONFIG_RTE_LIBRTE_EAL_LINUXAPP) += eal_common_log.c
 SRCS-$(CONFIG_RTE_LIBRTE_EAL_LINUXAPP) += eal_common_launch.c
diff --git a/lib/librte_eal/linuxapp/eal/eal_timer.c b/lib/librte_eal/linuxapp/eal/eal_timer.c
index 94909ed..76a8a65 100644
--- a/lib/librte_eal/linuxapp/eal/eal_timer.c
+++ b/lib/librte_eal/linuxapp/eal/eal_timer.c
@@ -57,9 +57,6 @@
 
 enum timer_source eal_timer_source = EAL_TIMER_HPET;
 
-/* The frequency of the RDTSC timer resolution */
-static uint64_t eal_tsc_resolution_hz = 0;
-
 #ifdef RTE_LIBEAL_USE_HPET
 
 #define DEV_HPET "/dev/hpet"
@@ -160,23 +157,6 @@ rte_get_hpet_cycles(void)
 
 #endif
 
-
-void
-rte_delay_us(unsigned us)
-{
-	const uint64_t start = rte_get_timer_cycles();
-	const uint64_t ticks = (uint64_t)us * rte_get_timer_hz() / 1E6;
-	while ((rte_get_timer_cycles() - start) < ticks)
-		rte_pause();
-}
-
-uint64_t
-rte_get_tsc_hz(void)
-{
-	return eal_tsc_resolution_hz;
-}
-
-
 #ifdef RTE_LIBEAL_USE_HPET
 /*
  * Open and mmap /dev/hpet (high precision event timer) that will
@@ -275,8 +255,8 @@ check_tsc_flags(void)
 	fclose(stream);
 }
 
-static int
-set_tsc_freq_from_clock(void)
+uint64_t
+get_tsc_freq(void)
 {
 #ifdef CLOCK_MONOTONIC_RAW
 #define NS_PER_SEC 1E9
@@ -284,6 +264,7 @@ set_tsc_freq_from_clock(void)
 	struct timespec sleeptime = {.tv_nsec = 5E8 }; /* 1/2 second */
 
 	struct timespec t_start, t_end;
+	uint64_t tsc_hz;
 
 	if (clock_gettime(CLOCK_MONOTONIC_RAW, &t_start) == 0) {
 		uint64_t ns, end, start = rte_rdtsc();
@@ -294,40 +275,11 @@ set_tsc_freq_from_clock(void)
 		ns += (t_end.tv_nsec - t_start.tv_nsec);
 
 		double secs = (double)ns/NS_PER_SEC;
-		eal_tsc_resolution_hz = (uint64_t)((end - start)/secs);
-		return 0;
+		tsc_hz = (uint64_t)((end - start)/secs);
+		return tsc_hz;
 	}
 #endif
-	return -1;
-}
-
-static void
-set_tsc_freq_fallback(void)
-{
-	RTE_LOG(WARNING, EAL, "WARNING: clock_gettime cannot use "
-			"CLOCK_MONOTONIC_RAW and HPET is not available"
-			" - clock timings may be less accurate.\n");
-	/* assume that the sleep(1) will sleep for 1 second */
-	uint64_t start = rte_rdtsc();
-	sleep(1);
-	eal_tsc_resolution_hz = rte_rdtsc() - start;
-}
-/*
- * This function measures the TSC frequency. It uses a variety of approaches.
- *
- * 1. If kernel provides CLOCK_MONOTONIC_RAW we use that to tune the TSC value
- * 2. If kernel does not provide that, and we have HPET support, tune using HPET
- * 3. Lastly, if neither of the above can be used, just sleep for 1 second and
- * tune off that, printing a warning about inaccuracy of timing
- */
-static void
-set_tsc_freq(void)
-{
-	if (set_tsc_freq_from_clock() < 0)
-		set_tsc_freq_fallback();
-
-	RTE_LOG(INFO, EAL, "TSC frequency is ~%"PRIu64" KHz\n",
-			eal_tsc_resolution_hz/1000);
+	return 0;
 }
 
 int
-- 
2.4.2