05/05/2022 08:11, Tyler Retzlaff пишет:
On Wed, May 04, 2022 at 11:55:57PM +0100, Konstantin Ananyev wrote:
04/05/2022 16:46, Tyler Retzlaff пишет:
Provide a portable type-safe thread identifier.
Provide rte_thread_self for obtaining current thread identifier.

Signed-off-by: Narcisa Vasile <navas...@microsoft.com>
Signed-off-by: Tyler Retzlaff <roret...@linux.microsoft.com>
Acked-by: Dmitry Kozlyuk <dmitry.kozl...@gmail.com>
---
  lib/eal/include/rte_thread.h | 22 ++++++++++++++++++++++
  lib/eal/unix/rte_thread.c    | 11 +++++++++++
  lib/eal/version.map          |  3 +++
  lib/eal/windows/rte_thread.c | 10 ++++++++++
  4 files changed, 46 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 */


I know that currently on linux typeof(pthread_id) == unsigned long int.
Though wouldn't it be safer and cleaner to use pthread_t explicitly
on posix-like systems?

i believe the previous discussions are.

* preference for reduced or no conditional compilation.
* preference for sizeof(type) to be `the same' on all platforms.


It would be the same as long as sizes of pthread_t uintptr_t are equal.

* preference for platform agnostic headers. i.e. don't drag
   platform specific headers into the application namespace when
   including rte_xxx.h headers.
Something like:
typedef struct {
#ifdef WINDOWS
        uintptr_t opaque_id;
#else
        pthread_t opaque_id;
#endif
};
AFAIK POSIX itself doesn't require pthread_t to be an 'arithmetic type'.

yes, this is correct. newer posix introduced this to allow the use of
structs. i assume prior reviewers are aware of the recent posix
standard (or should be).

this type makes no attempt to be usable on platforms that use
a handle > sizeof(uintptr_t). though any platform that does is free
to shove a pointer to struct into the handle at the cost of a
dereference if that is their implementation.

Using pthread_t directly still seems like a safest bet to me.
Then we can avoid doing these explicit type conversions before/after each pthread_xxx() call and wouldn't need to worry if we'll ever have platform with bigger pthread_t (though yes, I admit it is very unlikely).
But, if we still prefer to go ahead with 'arch-neutral' approach,
then I think we need to have compilation time check that opaque_id
is big enough to hold pthread_t value:
RTE_BUILD_BUG_ON(sizeof(pthread_t) != sizeof(opaque_id)) or so.





+} 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..82e008f 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 +16,16 @@ struct eal_tls_key {
        pthread_key_t thread_index;
  };
+rte_thread_t
+rte_thread_self(void)
+{
+       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 *))

Reply via email to