[PATCH v6 1/3] eal: add basic thread ID and current thread identifier API

[Tyler Retzlaff <roretzla@linux.microsoft.com>]

Provide a portable type-safe thread identifier.
Provide rte_thread_self for obtaining current thread identifier.

Signed-off-by: Narcisa Vasile <navasile@microsoft.com>
Signed-off-by: Tyler Retzlaff <roretzla@linux.microsoft.com>
Acked-by: Dmitry Kozlyuk <dmitry.kozliuk@gmail.com>
---
 lib/eal/include/rte_thread.h | 22 ++++++++++++++++++++++
 lib/eal/unix/rte_thread.c    | 13 +++++++++++++
 lib/eal/version.map          |  3 +++
 lib/eal/windows/rte_thread.c | 10 ++++++++++
 4 files changed, 48 insertions(+)

diff --git a/lib/eal/include/rte_thread.h b/lib/eal/include/rte_thread.h
index 8be8ed8..14478ba 100644
--- a/lib/eal/include/rte_thread.h
+++ b/lib/eal/include/rte_thread.h
@@ -1,7 +1,10 @@
 /* SPDX-License-Identifier: BSD-3-Clause
  * Copyright(c) 2021 Mellanox Technologies, Ltd
+ * Copyright (C) 2022 Microsoft Corporation
  */
 
+#include <stdint.h>
+
 #include <rte_os.h>
 #include <rte_compat.h>
 
@@ -21,10 +24,29 @@
 #endif
 
 /**
+ * Thread id descriptor.
+ */
+typedef struct {
+	uintptr_t opaque_id; /**< thread identifier */
+} rte_thread_t;
+
+/**
  * TLS key type, an opaque pointer.
  */
 typedef struct eal_tls_key *rte_thread_key;
 
+/**
+ * @warning
+ * @b EXPERIMENTAL: this API may change without prior notice.
+ *
+ * Get the id of the calling thread.
+ *
+ * @return
+ *   Return the thread id of the calling thread.
+ */
+__rte_experimental
+rte_thread_t rte_thread_self(void);
+
 #ifdef RTE_HAS_CPUSET
 
 /**
diff --git a/lib/eal/unix/rte_thread.c b/lib/eal/unix/rte_thread.c
index c34ede9..5e5beb1 100644
--- a/lib/eal/unix/rte_thread.c
+++ b/lib/eal/unix/rte_thread.c
@@ -1,5 +1,6 @@
 /* SPDX-License-Identifier: BSD-3-Clause
  * Copyright 2021 Mellanox Technologies, Ltd
+ * Copyright (C) 2022 Microsoft Corporation
  */
 
 #include <errno.h>
@@ -15,6 +16,18 @@ struct eal_tls_key {
 	pthread_key_t thread_index;
 };
 
+rte_thread_t
+rte_thread_self(void)
+{
+	RTE_BUILD_BUG_ON(sizeof(pthread_t) > sizeof(uintptr_t));
+
+	rte_thread_t thread_id;
+
+	thread_id.opaque_id = (uintptr_t)pthread_self();
+
+	return thread_id;
+}
+
 int
 rte_thread_key_create(rte_thread_key *key, void (*destructor)(void *))
 {
diff --git a/lib/eal/version.map b/lib/eal/version.map
index b53eeb3..05ce8f9 100644
--- a/lib/eal/version.map
+++ b/lib/eal/version.map
@@ -420,6 +420,9 @@ EXPERIMENTAL {
 	rte_intr_instance_free;
 	rte_intr_type_get;
 	rte_intr_type_set;
+
+	# added in 22.07
+	rte_thread_self;
 };
 
 INTERNAL {
diff --git a/lib/eal/windows/rte_thread.c b/lib/eal/windows/rte_thread.c
index 667287c..59fed3c 100644
--- a/lib/eal/windows/rte_thread.c
+++ b/lib/eal/windows/rte_thread.c
@@ -11,6 +11,16 @@ struct eal_tls_key {
 	DWORD thread_index;
 };
 
+rte_thread_t
+rte_thread_self(void)
+{
+	rte_thread_t thread_id;
+
+	thread_id.opaque_id = GetCurrentThreadId();
+
+	return thread_id;
+}
+
 int
 rte_thread_key_create(rte_thread_key *key,
 		__rte_unused void (*destructor)(void *))
-- 
1.8.3.1