[dpdk-dev] [RFC PATCH 1/7] eal: add linear thread id as pthread-local variable

[Cunming Liang]

Signed-off-by: Cunming Liang <cunming.liang at intel.com>
---
 lib/librte_eal/common/include/rte_eal.h   |   5 ++
 lib/librte_eal/common/include/rte_lcore.h |  12 ++++
 lib/librte_eal/linuxapp/eal/eal_thread.c  | 115 ++++++++++++++++++++++++++++--
 3 files changed, 126 insertions(+), 6 deletions(-)

diff --git a/lib/librte_eal/common/include/rte_eal.h b/lib/librte_eal/common/include/rte_eal.h
index f4ecd2e..2640167 100644
--- a/lib/librte_eal/common/include/rte_eal.h
+++ b/lib/librte_eal/common/include/rte_eal.h
@@ -262,6 +262,11 @@ rte_set_application_usage_hook( rte_usage_hook_t usage_func );
  */
 int rte_eal_has_hugepages(void);
 
+#ifndef RTE_MAX_THREAD
+#define RTE_MAX_THREAD                RTE_MAX_LCORE
+#endif
+
+
 #ifdef __cplusplus
 }
 #endif
diff --git a/lib/librte_eal/common/include/rte_lcore.h b/lib/librte_eal/common/include/rte_lcore.h
index 49b2c03..cd83d47 100644
--- a/lib/librte_eal/common/include/rte_lcore.h
+++ b/lib/librte_eal/common/include/rte_lcore.h
@@ -73,6 +73,7 @@ struct lcore_config {
 extern struct lcore_config lcore_config[RTE_MAX_LCORE];
 
 RTE_DECLARE_PER_LCORE(unsigned, _lcore_id); /**< Per core "core id". */
+RTE_DECLARE_PER_LCORE(unsigned, _thread_id); /**< Per thread "linear tid". */
 
 /**
  * Return the ID of the execution unit we are running on.
@@ -86,6 +87,17 @@ rte_lcore_id(void)
 }
 
 /**
+ * Return the linear thread ID of the cache unit we are running on.
+ * @return
+ *   core ID
+ */
+static inline unsigned long
+rte_linear_thread_id(void)
+{
+	return RTE_PER_LCORE(_thread_id);
+}
+
+/**
  * Get the id of the master lcore
  *
  * @return
diff --git a/lib/librte_eal/linuxapp/eal/eal_thread.c b/lib/librte_eal/linuxapp/eal/eal_thread.c
index 80a985f..52478d6 100644
--- a/lib/librte_eal/linuxapp/eal/eal_thread.c
+++ b/lib/librte_eal/linuxapp/eal/eal_thread.c
@@ -39,6 +39,7 @@
 #include <pthread.h>
 #include <sched.h>
 #include <sys/queue.h>
+#include <string.h>
 
 #include <rte_debug.h>
 #include <rte_atomic.h>
@@ -51,12 +52,19 @@
 #include <rte_eal.h>
 #include <rte_per_lcore.h>
 #include <rte_lcore.h>
+#include <rte_spinlock.h>
+#include <rte_common.h>
 
 #include "eal_private.h"
 #include "eal_thread.h"
 
+#define LINEAR_THREAD_ID_POOL        "THREAD_ID_POOL"
+
 RTE_DEFINE_PER_LCORE(unsigned, _lcore_id);
 
+/* define linear thread id as thread-local variables */
+RTE_DEFINE_PER_LCORE(unsigned, _thread_id);
+
 /*
  * Send a message to a slave lcore identified by slave_id to call a
  * function f with argument arg. Once the execution is done, the
@@ -94,12 +102,13 @@ rte_eal_remote_launch(int (*f)(void *), void *arg, unsigned slave_id)
 	return 0;
 }
 
+
 /* set affinity for current thread */
 static int
-eal_thread_set_affinity(void)
+__eal_thread_set_affinity(pthread_t thread, unsigned lcore)
 {
+
 	int s;
-	pthread_t thread;
 
 /*
  * According to the section VERSIONS of the CPU_ALLOC man page:
@@ -126,9 +135,8 @@ eal_thread_set_affinity(void)
 
 	size = CPU_ALLOC_SIZE(RTE_MAX_LCORE);
 	CPU_ZERO_S(size, cpusetp);
-	CPU_SET_S(rte_lcore_id(), size, cpusetp);
+	CPU_SET_S(lcore, size, cpusetp);
 
-	thread = pthread_self();
 	s = pthread_setaffinity_np(thread, size, cpusetp);
 	if (s != 0) {
 		RTE_LOG(ERR, EAL, "pthread_setaffinity_np failed\n");
@@ -140,9 +148,8 @@ eal_thread_set_affinity(void)
 #else /* CPU_ALLOC */
 	cpu_set_t cpuset;
 	CPU_ZERO( &cpuset );
-	CPU_SET( rte_lcore_id(), &cpuset );
+	CPU_SET(lcore, &cpuset );
 
-	thread = pthread_self();
 	s = pthread_setaffinity_np(thread, sizeof( cpuset ), &cpuset);
 	if (s != 0) {
 		RTE_LOG(ERR, EAL, "pthread_setaffinity_np failed\n");
@@ -152,6 +159,15 @@ eal_thread_set_affinity(void)
 	return 0;
 }
 
+/* set affinity for current thread */
+static int
+eal_thread_set_affinity(void)
+{
+	pthread_t thread = pthread_self();
+
+	return __eal_thread_set_affinity(thread, rte_lcore_id());
+}
+
 void eal_thread_init_master(unsigned lcore_id)
 {
 	/* set the lcore ID in per-lcore memory area */
@@ -162,6 +178,87 @@ void eal_thread_init_master(unsigned lcore_id)
 		rte_panic("cannot set affinity\n");
 }
 
+/* linear thread id control block */
+struct eal_thread_cb {
+	rte_spinlock_t lock;
+	uint64_t nb_bucket;
+	uint64_t bitmap[0];
+};
+
+static struct eal_thread_cb *
+__create_tid_pool(void)
+{
+	const struct rte_memzone *mz;
+	struct eal_thread_cb *pcb;
+	uint64_t sz;
+	uint64_t nb_bucket;
+
+	nb_bucket = RTE_ALIGN_CEIL(RTE_MAX_THREAD, 64) / 64;
+	sz = sizeof(*pcb) + nb_bucket * sizeof(uint64_t);
+	mz = rte_memzone_reserve(LINEAR_THREAD_ID_POOL,
+				 sz, rte_socket_id(), 0);
+	if (mz == NULL)
+		rte_panic("Cannot allocate linear thread ID pool\n");
+
+	pcb = mz->addr;
+	rte_spinlock_init(&pcb->lock);
+	pcb->nb_bucket = nb_bucket;
+	memset(pcb->bitmap, 0, nb_bucket * sizeof(uint64_t));
+
+	return pcb;
+}
+
+static int
+__get_linear_tid(uint64_t *tid)
+{
+	const struct rte_memzone *mz;
+	struct eal_thread_cb *pcb;
+	uint64_t i;
+	uint8_t shift = 0;
+
+	mz = rte_memzone_lookup(LINEAR_THREAD_ID_POOL);
+	if (mz != NULL)
+		pcb = mz->addr;
+	else
+		pcb = __create_tid_pool();
+
+	rte_spinlock_lock(&pcb->lock);
+	for (i = 0; i < pcb->nb_bucket; i++) {
+		if (pcb->bitmap[i] == (uint64_t)-1)
+			continue;
+		shift = 0; 
+		while (pcb->bitmap[i] & (1UL << shift))
+			shift ++;
+		pcb->bitmap[i] |= (1UL << shift);
+		break;
+	}
+	rte_spinlock_unlock(&pcb->lock);
+
+	if (i == pcb->nb_bucket)
+		return -1;
+
+	*tid = i * 64 + shift;
+	return 0;
+}
+
+static void __rte_unused
+__put_linear_tid(uint64_t tid)
+{
+	const struct rte_memzone *mz;
+	struct eal_thread_cb *pcb;
+	uint8_t shift;
+
+	mz = rte_memzone_lookup(LINEAR_THREAD_ID_POOL);
+	if (!mz)
+		return;
+
+	pcb = mz->addr;
+	rte_spinlock_lock(&pcb->lock);
+	shift = tid & 0x3F;
+	pcb->bitmap[tid / 64] &= ~(1UL << shift);
+	rte_spinlock_unlock(&pcb->lock);	
+}
+
 /* main loop of threads */
 __attribute__((noreturn)) void *
 eal_thread_loop(__attribute__((unused)) void *arg)
@@ -169,6 +266,7 @@ eal_thread_loop(__attribute__((unused)) void *arg)
 	char c;
 	int n, ret;
 	unsigned lcore_id;
+	unsigned long ltid = 0;
 	pthread_t thread_id;
 	int m2s, s2m;
 
@@ -191,6 +289,11 @@ eal_thread_loop(__attribute__((unused)) void *arg)
 	/* set the lcore ID in per-lcore memory area */
 	RTE_PER_LCORE(_lcore_id) = lcore_id;
 
+	/* set the linear thread ID in per-lcore memory area */
+	if (__get_linear_tid(&ltid) < 0)
+		rte_panic("cannot get cache slot id\n");
+	RTE_PER_LCORE(_thread_id) = ltid;
+
 	/* set CPU affinity */
 	if (eal_thread_set_affinity() < 0)
 		rte_panic("cannot set affinity\n");
-- 
1.8.1.4