[PATCH v2] eal/linux: enhanced error handling for affinity

[Jianyue Wu <wujianyue000@163.com>]

Improve the robustness of setting thread affinity in DPDK
by adding detailed error logging.

Changes:
1. Check the return value of pthread_setaffinity_np() and log an error
if the call fails.
2. Include the current thread name, the intended CPU set, and a detailed
error message in the log.

Sample prints:
EAL: Cannot set affinity for thread dpdk-test with cpus 0,
ret: 22, errno: 0, error description: Success
EAL: Cannot set affinity for thread dpdk-worker1 with cpus 1,
ret: 22, errno: 0, error description: Success

Signed-off-by: Jianyue Wu <wujianyue000@163.com>
---
 lib/eal/common/eal_common_thread.c |  2 +-
 lib/eal/common/eal_thread.h        |  2 +-
 lib/eal/unix/rte_thread.c          | 22 ++++++++++++++++++++--
 3 files changed, 22 insertions(+), 4 deletions(-)

diff --git a/lib/eal/common/eal_common_thread.c b/lib/eal/common/eal_common_thread.c
index a53bc639ae..31a2fab2a7 100644
--- a/lib/eal/common/eal_common_thread.c
+++ b/lib/eal/common/eal_common_thread.c
@@ -103,7 +103,7 @@ rte_thread_get_affinity(rte_cpuset_t *cpusetp)
 }
 
 int
-eal_thread_dump_affinity(rte_cpuset_t *cpuset, char *str, unsigned int size)
+eal_thread_dump_affinity(const rte_cpuset_t *cpuset, char *str, unsigned int size)
 {
 	unsigned cpu;
 	int ret;
diff --git a/lib/eal/common/eal_thread.h b/lib/eal/common/eal_thread.h
index 1c3c3442d3..85ab84baa5 100644
--- a/lib/eal/common/eal_thread.h
+++ b/lib/eal/common/eal_thread.h
@@ -50,7 +50,7 @@ unsigned eal_cpu_socket_id(unsigned cpu_id);
  *   0 for success, -1 if truncation happens.
  */
 int
-eal_thread_dump_affinity(rte_cpuset_t *cpuset, char *str, unsigned int size);
+eal_thread_dump_affinity(const rte_cpuset_t *cpuset, char *str, unsigned int size);
 
 /**
  * Dump the current thread cpuset.
diff --git a/lib/eal/unix/rte_thread.c b/lib/eal/unix/rte_thread.c
index 1b4c73f58e..8f9eaf0dcf 100644
--- a/lib/eal/unix/rte_thread.c
+++ b/lib/eal/unix/rte_thread.c
@@ -369,8 +369,26 @@ int
 rte_thread_set_affinity_by_id(rte_thread_t thread_id,
 		const rte_cpuset_t *cpuset)
 {
-	return pthread_setaffinity_np((pthread_t)thread_id.opaque_id,
-		sizeof(*cpuset), cpuset);
+	int ret;
+	char cpus_str[RTE_CPU_AFFINITY_STR_LEN] = {'\0'};
+	char thread_name[RTE_MAX_THREAD_NAME_LEN] = {'\0'};
+
+	errno = 0;
+	ret = pthread_setaffinity_np((pthread_t)thread_id.opaque_id,
+				sizeof(*cpuset), cpuset);
+	if (ret != 0) {
+		if (pthread_getname_np((pthread_t)thread_id.opaque_id,
+					thread_name, sizeof(thread_name)) != 0)
+			EAL_LOG(ERR, "pthread_getname_np failed!");
+		if (eal_thread_dump_affinity(cpuset, cpus_str, RTE_CPU_AFFINITY_STR_LEN) != 0)
+			EAL_LOG(ERR, "eal_thread_dump_affinity failed!");
+		EAL_LOG(ERR, "Cannot set affinity for thread %s with cpus %s, "
+			"ret: %d, errno: %d, error description: %s",
+			thread_name, cpus_str,
+			ret, errno, strerror(errno));
+	}
+
+	return ret;
 }
 
 int
-- 
2.34.1