DPDK allows calling some part of its API from a non-EAL thread but this
has some limitations.
OVS (and other applications) has its own thread management but still
want to avoid such limitations by hacking RTE_PER_LCORE(_lcore_id) and
faking EAL threads potentially unknown of some DPDK component.
Introduce a new API to register non-EAL thread and associate them to a
free lcore with a new EXTERNAL role.
This role denotes lcores that do not run DPDK mainloop and as such
prevents use of rte_eal_wait_lcore() and consorts.
Signed-off-by: David Marchand <david.march...@redhat.com>
---
doc/guides/howto/debug_troubleshoot.rst | 5 ++-
lib/librte_eal/common/eal_common_lcore.c | 44 +++++++++++++++++--
lib/librte_eal/common/eal_common_thread.c | 45 ++++++++++++++++++++
lib/librte_eal/common/eal_private.h | 17 ++++++++
lib/librte_eal/include/rte_eal.h | 9 ----
lib/librte_eal/include/rte_lcore.h | 52 +++++++++++++++++------
lib/librte_eal/rte_eal_version.map | 4 ++
7 files changed, 147 insertions(+), 29 deletions(-)
diff --git a/doc/guides/howto/debug_troubleshoot.rst
b/doc/guides/howto/debug_troubleshoot.rst
index cef016b2fe..056f556a73 100644
--- a/doc/guides/howto/debug_troubleshoot.rst
+++ b/doc/guides/howto/debug_troubleshoot.rst
@@ -307,8 +307,9 @@ Custom worker function :numref:`dtg_distributor_worker`.
#. Configuration issue isolation
- * Identify core role using ``rte_eal_lcore_role`` to identify RTE, OFF and
- SERVICE. Check performance functions are mapped to run on the cores.
+ * Identify core role using ``rte_eal_lcore_role`` to identify RTE, OFF,
+ SERVICE and EXTERNAL. Check performance functions are mapped to run on the
+ cores.
* For high-performance execution logic ensure running it on correct NUMA
and non-master core.
diff --git a/lib/librte_eal/common/eal_common_lcore.c
b/lib/librte_eal/common/eal_common_lcore.c
index 5404922a87..35d6c1295e 100644
--- a/lib/librte_eal/common/eal_common_lcore.c
+++ b/lib/librte_eal/common/eal_common_lcore.c
@@ -6,13 +6,15 @@
#include <limits.h>
#include <string.h>
-#include <rte_errno.h>
-#include <rte_log.h>
-#include <rte_eal.h>
-#include <rte_lcore.h>
#include <rte_common.h>
#include <rte_debug.h>
+#include <rte_eal.h>
+#include <rte_errno.h>
+#include <rte_lcore.h>
+#include <rte_log.h>
+#include <rte_spinlock.h>
+#include "eal_internal_cfg.h"
#include "eal_private.h"
#include "eal_thread.h"
@@ -209,3 +211,37 @@ rte_socket_id_by_idx(unsigned int idx)
}
return config->numa_nodes[idx];
}
+
+rte_spinlock_t external_lcore_lock = RTE_SPINLOCK_INITIALIZER;
+
+unsigned int
+eal_lcore_external_reserve(void)
+{
+ struct rte_config *cfg = rte_eal_get_configuration();
+ unsigned int lcore_id;
+
+ rte_spinlock_lock(&external_lcore_lock);
+ for (lcore_id = 0; lcore_id < RTE_MAX_LCORE; lcore_id++) {
+ if (rte_eal_lcore_role(lcore_id) != ROLE_OFF)
+ continue;
+ cfg->lcore_role[lcore_id] = ROLE_EXTERNAL;
+ cfg->lcore_count++;
+ break;
+ }
+ rte_spinlock_unlock(&external_lcore_lock);
+
+ return lcore_id;
+}
+
+void
+eal_lcore_external_release(unsigned int lcore_id)
+{
+ struct rte_config *cfg = rte_eal_get_configuration();
+
+ rte_spinlock_lock(&external_lcore_lock);
+ if (rte_eal_lcore_role(lcore_id) == ROLE_EXTERNAL) {
+ cfg->lcore_role[lcore_id] = ROLE_OFF;
+ cfg->lcore_count--;
+ }
+ rte_spinlock_unlock(&external_lcore_lock);
+}
diff --git a/lib/librte_eal/common/eal_common_thread.c
b/lib/librte_eal/common/eal_common_thread.c
index 8a973ca8ac..d57a6ec797 100644
--- a/lib/librte_eal/common/eal_common_thread.c
+++ b/lib/librte_eal/common/eal_common_thread.c
@@ -29,6 +29,7 @@ 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);
+static RTE_DEFINE_PER_LCORE(bool, thread_registered);
unsigned rte_socket_id(void)
{
@@ -255,3 +256,47 @@ rte_ctrl_thread_create(pthread_t *thread, const char *name,
pthread_join(*thread, NULL);
return -ret;
}
+
+void
+rte_thread_register(void)
+{
+ unsigned int lcore_id;
+ rte_cpuset_t cpuset;
+
+ /* EAL init flushes all lcores, we can't register before. */
+ assert(internal_config.init_complete == 1);
+
+ if (RTE_PER_LCORE(thread_registered))
+ return;
+
+ if (pthread_getaffinity_np(pthread_self(), sizeof(cpuset),
+ &cpuset) != 0)
+ CPU_ZERO(&cpuset);
+
+ lcore_id = eal_lcore_external_reserve();
+ if (lcore_id >= RTE_MAX_LCORE)
+ lcore_id = LCORE_ID_ANY;
+
+ rte_thread_init(lcore_id, &cpuset);
+
+ RTE_LOG(DEBUG, EAL, "Registered thread as lcore %u.\n", lcore_id);
+ RTE_PER_LCORE(thread_registered) = true;
+}
+
+void
+rte_thread_unregister(void)
+{
+ unsigned int lcore_id;
+
+ if (!RTE_PER_LCORE(thread_registered))
+ return;
+
+ lcore_id = RTE_PER_LCORE(_lcore_id);
+ if (lcore_id != LCORE_ID_ANY)
+ eal_lcore_external_release(lcore_id);
+
+ rte_thread_uninit();
+
+ RTE_LOG(DEBUG, EAL, "Unregistered thread (was lcore %u).\n", lcore_id);
+ RTE_PER_LCORE(thread_registered) = false;
+}
diff --git a/lib/librte_eal/common/eal_private.h
b/lib/librte_eal/common/eal_private.h
index 869ce183ad..8dd850f68a 100644
--- a/lib/librte_eal/common/eal_private.h
+++ b/lib/librte_eal/common/eal_private.h
@@ -274,6 +274,23 @@ uint64_t get_tsc_freq(void);
*/
uint64_t get_tsc_freq_arch(void);
+/**
+ * Ask for a free lcore to associate to a non-EAL thread.
+ *
+ * @return
+ * The id of a lcore with role ROLE_EXTERNAL or RTE_MAX_LCORE if none was
+ * available.
+ */
+unsigned int eal_lcore_external_reserve(void);
+
+/**
+ * Release an external lcore.
+ *
+ * @param lcore_id
+ * The lcore with role ROLE_EXTERNAL to release.
+ */
+void eal_lcore_external_release(unsigned int lcore_id);
+
/**
* Prepare physical memory mapping
* i.e. hugepages on Linux and
diff --git a/lib/librte_eal/include/rte_eal.h b/lib/librte_eal/include/rte_eal.h
index 2edf8c6556..0913d1947c 100644
--- a/lib/librte_eal/include/rte_eal.h
+++ b/lib/librte_eal/include/rte_eal.h
@@ -31,15 +31,6 @@ extern "C" {
/* Maximum thread_name length. */
#define RTE_MAX_THREAD_NAME_LEN 16
-/**
- * The lcore role (used in RTE or not).
- */
-enum rte_lcore_role_t {
- ROLE_RTE,
- ROLE_OFF,
- ROLE_SERVICE,
-};
-
/**
* The type of process in a linux, multi-process setup
*/
diff --git a/lib/librte_eal/include/rte_lcore.h
b/lib/librte_eal/include/rte_lcore.h
index 5c1d1926e9..d59c4edc67 100644
--- a/lib/librte_eal/include/rte_lcore.h
+++ b/lib/librte_eal/include/rte_lcore.h
@@ -24,6 +24,16 @@ extern "C" {
RTE_DECLARE_PER_LCORE(unsigned, _lcore_id); /**< Per thread "lcore id". */
+/**
+ * The lcore role (used in RTE or not).
+ */
+enum rte_lcore_role_t {
+ ROLE_RTE,
+ ROLE_OFF,
+ ROLE_SERVICE,
+ ROLE_EXTERNAL,
+};
+
/**
* Get a lcore's role.
*
@@ -34,6 +44,20 @@ RTE_DECLARE_PER_LCORE(unsigned, _lcore_id); /**< Per thread
"lcore id". */
*/
enum rte_lcore_role_t rte_eal_lcore_role(unsigned int lcore_id);
+/**
+ * Test if the core supplied has a specific role
+ *
+ * @param lcore_id
+ * The identifier of the lcore, which MUST be between 0 and
+ * RTE_MAX_LCORE-1.
+ * @param role
+ * The role to be checked against.
+ * @return
+ * Boolean value: positive if test is true; otherwise returns 0.
+ */
+int
+rte_lcore_has_role(unsigned int lcore_id, enum rte_lcore_role_t role);
+
/**
* Return the Application thread ID of the execution unit.
*
@@ -256,6 +280,20 @@ int rte_thread_setname(pthread_t id, const char *name);
__rte_experimental
int rte_thread_getname(pthread_t id, char *name, size_t len);
+/**
+ * Register current non-EAL thread as a lcore.
+ */
+__rte_experimental
+void
+rte_thread_register(void);
+
+/**
+ * Unregister current thread and release lcore if one was associated.
+ */
+__rte_experimental
+void
+rte_thread_unregister(void);
+
/**
* Create a control thread.
*
@@ -283,20 +321,6 @@ rte_ctrl_thread_create(pthread_t *thread, const char *name,
const pthread_attr_t *attr,
void *(*start_routine)(void *), void *arg);
-/**
- * Test if the core supplied has a specific role
- *
- * @param lcore_id
- * The identifier of the lcore, which MUST be between 0 and
- * RTE_MAX_LCORE-1.
- * @param role
- * The role to be checked against.
- * @return
- * Boolean value: positive if test is true; otherwise returns 0.
- */
-int
-rte_lcore_has_role(unsigned int lcore_id, enum rte_lcore_role_t role);
-
#ifdef __cplusplus
}
#endif
diff --git a/lib/librte_eal/rte_eal_version.map
b/lib/librte_eal/rte_eal_version.map
index fdfc3f1a88..f5b68d2815 100644
--- a/lib/librte_eal/rte_eal_version.map
+++ b/lib/librte_eal/rte_eal_version.map
@@ -393,4 +393,8 @@ EXPERIMENTAL {
rte_trace_point_lookup;
rte_trace_regexp;
rte_trace_save;
+
+ # added in 20.08
+ rte_thread_register;
+ rte_thread_unregister;
};
--
2.23.0
