[PATCH v8 4/5] eal: add option to put timestamp on console output

[Stephen Hemminger <stephen@networkplumber.org>]

When debugging driver or startup issues, it is useful to have
a timestamp on each message printed. The messages in syslog
already have a timestamp, but often syslog is not available
during testing. The timestamp format is chosen to look
like the default Linux dmesg timestamp.

The first few lines are not timestamped because the flag is stored
in internal configuration which is stored in shared memory
which is not setup up until a little later in startup process.

This logging skips the unnecessary step of going through stdio,
which makes it more robust against being called in interrupt
handlers etc.

Example:
$ dpdk-testpmd --log-timestamp -- -i
EAL: Detected CPU lcores: 16
EAL: Detected NUMA nodes: 1
EAL: Detected static linkage of DPDK
EAL: Multi-process socket /var/run/dpdk/rte/mp_socket
EAL: Selected IOVA mode 'VA'
[       0.112264] testpmd: No probed ethernet devices
Interactive-mode selected
[       0.184573] testpmd: create a new mbuf pool <mb_pool_0>: n=163456, size=2176, socket=0
[       0.184612] testpmd: preferred mempool ops selected: ring_mp_mc

Signed-off-by: Stephen Hemminger <stephen@networkplumber.org>
---
 app/test/test_eal_flags.c           |  9 ++++++++
 doc/guides/prog_guide/log_lib.rst   | 10 +++++++++
 lib/eal/common/eal_common_options.c | 10 +++++++--
 lib/eal/common/eal_options.h        |  2 ++
 lib/log/log_internal.h              |  9 ++++++++
 lib/log/log_unix.c                  | 32 +++++++++++++++++++++++++++--
 lib/log/log_windows.c               |  6 ++++++
 lib/log/version.map                 |  1 +
 8 files changed, 75 insertions(+), 4 deletions(-)

diff --git a/app/test/test_eal_flags.c b/app/test/test_eal_flags.c
index 6cb4b0675730..07a038fb6051 100644
--- a/app/test/test_eal_flags.c
+++ b/app/test/test_eal_flags.c
@@ -1055,6 +1055,10 @@ test_misc_flags(void)
 	const char * const argv22[] = {prgname, prefix, mp_flag,
 				       "--huge-worker-stack=512"};
 
+	/* Try running with --log-timestamp */
+	const char * const argv23[] = {prgname, prefix, mp_flag,
+				       "--log-timestamp" };
+
 	/* run all tests also applicable to FreeBSD first */
 
 	if (launch_proc(argv0) == 0) {
@@ -1162,6 +1166,11 @@ test_misc_flags(void)
 		printf("Error - process did not run ok with --huge-worker-stack=size parameter\n");
 		goto fail;
 	}
+	if (launch_proc(argv23) != 0) {
+		printf("Error - process did not run ok with --log-timestamp parameter\n");
+		goto fail;
+	}
+
 
 	rmdir(hugepath_dir3);
 	rmdir(hugepath_dir2);
diff --git a/doc/guides/prog_guide/log_lib.rst b/doc/guides/prog_guide/log_lib.rst
index aacb36c36ce0..1d6b2e3cea5d 100644
--- a/doc/guides/prog_guide/log_lib.rst
+++ b/doc/guides/prog_guide/log_lib.rst
@@ -73,6 +73,16 @@ For example::
 	/path/to/app --syslog local0
 
 
+Console timestamp
+~~~~~~~~~~~~~~~~~
+
+On Linux and FreeBSD, an optional timestamp can be added before each
+message by adding the ``--log-timestamp`` option.
+For example::
+
+	/path/to/app --log-level=lib.*:debug --log-timestamp
+
+
 Using Logging APIs to Generate Log Messages
 -------------------------------------------
 
diff --git a/lib/eal/common/eal_common_options.c b/lib/eal/common/eal_common_options.c
index 7310d10dfd78..9bc95433d27c 100644
--- a/lib/eal/common/eal_common_options.c
+++ b/lib/eal/common/eal_common_options.c
@@ -77,6 +77,7 @@ eal_long_options[] = {
 	{OPT_IOVA_MODE,	        1, NULL, OPT_IOVA_MODE_NUM        },
 	{OPT_LCORES,            1, NULL, OPT_LCORES_NUM           },
 	{OPT_LOG_LEVEL,         1, NULL, OPT_LOG_LEVEL_NUM        },
+	{OPT_LOG_TIMESTAMP,     0, NULL, OPT_LOG_TIMESTAMP_NUM    },
 	{OPT_TRACE,             1, NULL, OPT_TRACE_NUM            },
 	{OPT_TRACE_DIR,         1, NULL, OPT_TRACE_DIR_NUM        },
 	{OPT_TRACE_BUF_SIZE,    1, NULL, OPT_TRACE_BUF_SIZE_NUM   },
@@ -1663,6 +1664,7 @@ eal_log_level_parse(int argc, char * const argv[])
 
 		switch (opt) {
 		case OPT_LOG_LEVEL_NUM:
+		case OPT_LOG_TIMESTAMP_NUM:
 			if (eal_parse_common_option(opt, optarg, internal_conf) < 0)
 				return -1;
 			break;
@@ -1890,7 +1892,7 @@ eal_parse_common_option(int opt, const char *optarg,
 		break;
 #endif
 
-	case OPT_LOG_LEVEL_NUM: {
+	case OPT_LOG_LEVEL_NUM:
 		if (eal_parse_log_level(optarg) < 0) {
 			EAL_LOG(ERR,
 				"invalid parameters for --"
@@ -1898,7 +1900,10 @@ eal_parse_common_option(int opt, const char *optarg,
 			return -1;
 		}
 		break;
-	}
+
+	case OPT_LOG_TIMESTAMP_NUM:
+		eal_log_enable_timestamp();
+		break;
 
 #ifndef RTE_EXEC_ENV_WINDOWS
 	case OPT_TRACE_NUM: {
@@ -2261,6 +2266,7 @@ eal_common_usage(void)
 	       "  --"OPT_PROC_TYPE"         Type of this process (primary|secondary|auto)\n"
 #ifndef RTE_EXEC_ENV_WINDOWS
 	       "  --"OPT_SYSLOG"            Set syslog facility\n"
+	       "  --"OPT_LOG_TIMESTAMP"     Timestamp log output\n"
 #endif
 	       "  --"OPT_LOG_LEVEL"=<level> Set global log level\n"
 	       "  --"OPT_LOG_LEVEL"=<type-match>:<level>\n"
diff --git a/lib/eal/common/eal_options.h b/lib/eal/common/eal_options.h
index f3f2e104f6d7..e24c9eca53ca 100644
--- a/lib/eal/common/eal_options.h
+++ b/lib/eal/common/eal_options.h
@@ -35,6 +35,8 @@ enum {
 	OPT_LCORES_NUM,
 #define OPT_LOG_LEVEL         "log-level"
 	OPT_LOG_LEVEL_NUM,
+#define OPT_LOG_TIMESTAMP     "log-timestamp"
+	OPT_LOG_TIMESTAMP_NUM,
 #define OPT_TRACE             "trace"
 	OPT_TRACE_NUM,
 #define OPT_TRACE_DIR         "trace-dir"
diff --git a/lib/log/log_internal.h b/lib/log/log_internal.h
index c77e687e28bc..1af27fe8f9d3 100644
--- a/lib/log/log_internal.h
+++ b/lib/log/log_internal.h
@@ -5,8 +5,10 @@
 #ifndef LOG_INTERNAL_H
 #define LOG_INTERNAL_H
 
+#include <stdbool.h>
 #include <stdio.h>
 #include <stdint.h>
+#include <time.h>
 
 #include <rte_compat.h>
 
@@ -44,4 +46,11 @@ const char *eal_log_level2str(uint32_t level);
 __rte_internal
 void rte_eal_log_cleanup(void);
 
+/*
+ * Add timestamp to console logs
+ */
+__rte_internal
+void eal_log_enable_timestamp(void);
+
+
 #endif /* LOG_INTERNAL_H */
diff --git a/lib/log/log_unix.c b/lib/log/log_unix.c
index a415bae5774d..71ce366b6825 100644
--- a/lib/log/log_unix.c
+++ b/lib/log/log_unix.c
@@ -2,24 +2,52 @@
  * Copyright(c) 2010-2014 Intel Corporation
  */
 
+#include <stdbool.h>
 #include <stdio.h>
 #include <sys/types.h>
+#include <sys/uio.h>
 #include <syslog.h>
+#include <time.h>
+#include <unistd.h>
 
 #include <rte_log.h>
 
 #include "log_internal.h"
 
+static bool timestamp_enabled;
+static struct timespec log_started;
+
+void
+eal_log_enable_timestamp(void)
+{
+	timestamp_enabled = true;
+	clock_gettime(CLOCK_MONOTONIC, &log_started);
+}
+
 /*
  * default log function
  */
 static ssize_t
 console_log_write(__rte_unused void *c, const char *buf, size_t size)
 {
+	struct timespec ts;
 	ssize_t ret;
 
-	/* write on stderr */
-	ret = fwrite(buf, 1, size, stderr);
+	if (timestamp_enabled) {
+		clock_gettime(CLOCK_MONOTONIC, &ts);
+		ts.tv_sec -= log_started.tv_sec;
+		ts.tv_nsec -= log_started.tv_nsec;
+		if (ts.tv_nsec < 0) {
+			--ts.tv_sec;
+			ts.tv_nsec += 1000000000ul;
+		}
+
+		ret = fprintf(stderr, "[%8lu.%06lu] %.*s",
+			      ts.tv_sec, ts.tv_nsec / 1000u,
+			      (int) size, buf);
+	} else {
+		ret = fwrite(buf, 1, size, stderr);
+	}
 	fflush(stderr);
 
 	/* Syslog error levels are from 0 to 7, so subtract 1 to convert */
diff --git a/lib/log/log_windows.c b/lib/log/log_windows.c
index a6a08895501e..0c471bfb15f6 100644
--- a/lib/log/log_windows.c
+++ b/lib/log/log_windows.c
@@ -6,6 +6,12 @@
 #include <rte_log.h>
 #include "log_internal.h"
 
+void
+eal_log_enable_timestamp(void)
+{
+	/* not implemented */
+}
+
 /* set the log to default function, called during eal init process. */
 int
 eal_log_init(__rte_unused const char *id, __rte_unused int facility)
diff --git a/lib/log/version.map b/lib/log/version.map
index 6ecc656d1d65..32c555f29e79 100644
--- a/lib/log/version.map
+++ b/lib/log/version.map
@@ -25,6 +25,7 @@ DPDK_24 {
 INTERNAL {
 	global:
 
+	eal_log_enable_timestamp;
 	eal_log_get_default;
 	eal_log_init;
 	eal_log_level2str;
-- 
2.43.0