[dpdk-dev] [PATCH 2/7] eal: fix multiple definition of per lcore thread id

[David Marchand]

Because of the inline accessor + static declaration in rte_gettid(),
we end up with multiple symbols for RTE_PER_LCORE(_thread_id).
Each compilation unit will pay a cost when accessing this information
for the first time.

$ nm build/app/dpdk-testpmd | grep per_lcore__thread_id
0000000000000054 d per_lcore__thread_id.5037
0000000000000040 d per_lcore__thread_id.5103
0000000000000048 d per_lcore__thread_id.5259
000000000000004c d per_lcore__thread_id.5259
0000000000000044 d per_lcore__thread_id.5933
0000000000000058 d per_lcore__thread_id.6261
0000000000000050 d per_lcore__thread_id.7378
000000000000005c d per_lcore__thread_id.7496
000000000000000c d per_lcore__thread_id.8016
0000000000000010 d per_lcore__thread_id.8431

Make it global as part of the DPDK_21 stable ABI.

Fixes: ef76436c6834 ("eal: get unique thread id")

Signed-off-by: David Marchand <david.marchand at redhat.com>
---
 lib/librte_eal/common/eal_common_thread.c | 1 +
 lib/librte_eal/include/rte_eal.h          | 3 ++-
 lib/librte_eal/rte_eal_version.map        | 7 +++++++
 3 files changed, 10 insertions(+), 1 deletion(-)

diff --git a/lib/librte_eal/common/eal_common_thread.c b/lib/librte_eal/common/eal_common_thread.c
index 25200e5a99..f04d880880 100644
--- a/lib/librte_eal/common/eal_common_thread.c
+++ b/lib/librte_eal/common/eal_common_thread.c
@@ -24,6 +24,7 @@
 #include "eal_thread.h"
 
 RTE_DEFINE_PER_LCORE(unsigned int, _lcore_id) = LCORE_ID_ANY;
+RTE_DEFINE_PER_LCORE(int, _thread_id) = -1;
 static RTE_DEFINE_PER_LCORE(unsigned int, _socket_id) =
 	(unsigned int)SOCKET_ID_ANY;
 static RTE_DEFINE_PER_LCORE(rte_cpuset_t, _cpuset);
diff --git a/lib/librte_eal/include/rte_eal.h b/lib/librte_eal/include/rte_eal.h
index 2f9ed298de..2edf8c6556 100644
--- a/lib/librte_eal/include/rte_eal.h
+++ b/lib/librte_eal/include/rte_eal.h
@@ -447,6 +447,8 @@ enum rte_intr_mode rte_eal_vfio_intr_mode(void);
  */
 int rte_sys_gettid(void);
 
+RTE_DECLARE_PER_LCORE(int, _thread_id);
+
 /**
  * Get system unique thread id.
  *
@@ -456,7 +458,6 @@ int rte_sys_gettid(void);
  */
 static inline int rte_gettid(void)
 {
-	static RTE_DEFINE_PER_LCORE(int, _thread_id) = -1;
 	if (RTE_PER_LCORE(_thread_id) == -1)
 		RTE_PER_LCORE(_thread_id) = rte_sys_gettid();
 	return RTE_PER_LCORE(_thread_id);
diff --git a/lib/librte_eal/rte_eal_version.map b/lib/librte_eal/rte_eal_version.map
index d8038749a4..fdfc3f1a88 100644
--- a/lib/librte_eal/rte_eal_version.map
+++ b/lib/librte_eal/rte_eal_version.map
@@ -221,6 +221,13 @@ DPDK_20.0 {
 	local: *;
 };
 
+DPDK_21 {
+	global:
+
+	per_lcore__thread_id;
+
+} DPDK_20.0;
+
 EXPERIMENTAL {
 	global:
 
-- 
2.23.0