From b72fcd6421f599422d76a969795a7f523c405684 Mon Sep 17 00:00:00 2001
From: jiangheng12 <jiangheng14@huawei.com>
Date: Fri, 10 Mar 2023 19:54:47 +0800
Subject: [PATCH] when send ring full whether dynamic alloc mbuf is
 configurable reduce cpu usage when send ring full

---
 src/common/gazelle_opt.h        |  3 +++
 src/lstack/core/lstack_cfg.c    |  7 +++++
 src/lstack/core/lstack_lwip.c   | 46 +++++++++++++++++++++++++++++----
 src/lstack/include/lstack_cfg.h |  1 +
 src/lstack/lstack.conf          |  4 +++
 5 files changed, 56 insertions(+), 5 deletions(-)

diff --git a/src/common/gazelle_opt.h b/src/common/gazelle_opt.h
index 76b89ce..745fdd8 100644
--- a/src/common/gazelle_opt.h
+++ b/src/common/gazelle_opt.h
@@ -87,4 +87,7 @@
 #define GAZELLE_RUN_DIR                  "/var/run/gazelle/"
 #define GAZELLE_FILE_PERMISSION          0700
 
+#define SEND_TIME_WAIT_NS 20000
+#define SECOND_NSECOND 1000000000
+
 #endif /* _GAZELLE_OPT_H_ */
diff --git a/src/lstack/core/lstack_cfg.c b/src/lstack/core/lstack_cfg.c
index 1f7dda1..86d0f14 100644
--- a/src/lstack/core/lstack_cfg.c
+++ b/src/lstack/core/lstack_cfg.c
@@ -65,6 +65,7 @@ static int32_t parse_nic_read_number(void);
 static int32_t parse_tcp_conn_count(void);
 static int32_t parse_mbuf_count_per_conn(void);
 static int32_t parse_send_ring_size(void);
+static int32_t parse_expand_send_ring(void);
 
 static inline int32_t parse_int(void *arg, char * arg_string, int32_t default_val,
                              int32_t min_val, int32_t max_val)
@@ -112,6 +113,7 @@ static struct config_vector_t g_config_tbl[] = {
     { "rpc_number", parse_rpc_number },
     { "nic_read_number", parse_nic_read_number },
     { "send_ring_size", parse_send_ring_size },
+    { "expand_send_ring", parse_expand_send_ring },
     { NULL,           NULL }
 };
 
@@ -721,6 +723,11 @@ static int32_t parse_send_ring_size(void)
     return parse_int(&g_config_params.send_ring_size, "send_ring_size", 32, 1, SOCK_SEND_RING_SIZE_MAX);
 }
 
+static int32_t parse_expand_send_ring(void)
+{
+    return parse_int(&g_config_params.expand_send_ring, "expand_send_ring", 0, 0, 1);
+}
+
 static int32_t parse_mbuf_count_per_conn(void)
 {
     return parse_int(&g_config_params.mbuf_count_per_conn, "mbuf_count_per_conn",
diff --git a/src/lstack/core/lstack_lwip.c b/src/lstack/core/lstack_lwip.c
index b9f97e0..dcd7e05 100644
--- a/src/lstack/core/lstack_lwip.c
+++ b/src/lstack/core/lstack_lwip.c
@@ -126,10 +126,12 @@ static struct pbuf *init_mbuf_to_pbuf(struct rte_mbuf *mbuf, pbuf_layer layer, u
 }
 
 /* true: need replenish again */
-static bool replenish_send_idlembuf(struct protocol_stack *stack, struct rte_ring *ring)
+static bool replenish_send_idlembuf(struct protocol_stack *stack, struct lwip_sock *sock)
 {
     void *pbuf[SOCK_SEND_RING_SIZE_MAX];
 
+    struct rte_ring *ring = sock->send_ring;
+
     uint32_t replenish_cnt = gazelle_ring_free_count(ring);
     if (replenish_cnt == 0) {
         return false;
@@ -152,6 +154,10 @@ static bool replenish_send_idlembuf(struct protocol_stack *stack, struct rte_rin
         pbuf_free(pbuf[i]);
     }
 
+    if (!get_global_cfg_params()->expand_send_ring) {
+        sem_post(&sock->snd_ring_sem);
+    }
+
     return false;
 }
 
@@ -181,7 +187,7 @@ void gazelle_init_sock(int32_t fd)
         LSTACK_LOG(ERR, LSTACK, "sock_send create failed. errno: %d.\n", rte_errno);
         return;
     }
-    (void)replenish_send_idlembuf(stack, sock->send_ring);
+    (void)replenish_send_idlembuf(stack, sock);
 
     sock->stack = stack;
     sock->stack->conn_num++;
@@ -490,6 +496,17 @@ static inline size_t merge_data_lastpbuf(struct lwip_sock *sock, void *buf, size
     return send_len;
 }
 
+int sem_timedwait_nsecs(sem_t *sem)
+{
+    struct timespec ts;
+    clock_gettime(CLOCK_REALTIME, &ts);
+    long long wait_nsec = ts.tv_nsec + SEND_TIME_WAIT_NS;
+    ts.tv_nsec = wait_nsec % SECOND_NSECOND;
+    long add = wait_nsec / SECOND_NSECOND;
+    ts.tv_sec += add;
+    return sem_timedwait(sem, &ts);
+}
+
 ssize_t write_stack_data(struct lwip_sock *sock, const void *buf, size_t len)
 {
     if (sock->errevent > 0) {
@@ -518,6 +535,16 @@ ssize_t write_stack_data(struct lwip_sock *sock, const void *buf, size_t len)
 
     /* send_ring is full, data attach last pbuf */
     if (write_avail == 0) {
+        if (!get_global_cfg_params()->expand_send_ring) {
+            sem_timedwait_nsecs(&sock->snd_ring_sem);
+            if (likely(sock->send_ring != NULL)) {
+                write_avail = gazelle_ring_readable_count(sock->send_ring);
+            }
+            goto END;
+        }
+        if (unlikely(sock->send_ring == NULL)) {
+            goto END;
+        }
         struct pbuf *last_pbuf = gazelle_ring_readlast(sock->send_ring);
         if (last_pbuf) {
             send_len += app_direct_attach(stack, last_pbuf, (char *)buf + send_len, len - send_len, write_num);
@@ -536,8 +563,17 @@ ssize_t write_stack_data(struct lwip_sock *sock, const void *buf, size_t len)
     }
 
     /* send_ring have idle */
-    send_len += (write_num <= write_avail) ? app_buff_write(sock, (char *)buf + send_len, len - send_len, write_num) :
-        app_direct_write(stack, sock, (char *)buf + send_len, len - send_len, write_num);
+    if (get_global_cfg_params()->expand_send_ring) {
+        send_len += (write_num <= write_avail) ? app_buff_write(sock, (char *)buf + send_len, len - send_len, write_num) :
+            app_direct_write(stack, sock, (char *)buf + send_len, len - send_len, write_num);
+    } else {
+        if (write_num > write_avail) {
+            write_num = write_avail;
+            len = write_num * MBUF_MAX_DATA_LEN;
+        }
+        send_len += app_buff_write(sock, (char *)buf + send_len, len - send_len, write_num);
+    }
+
     if (wakeup) {
         wakeup->stat.app_write_cnt += write_num;
     }
@@ -558,7 +594,7 @@ static inline bool replenish_send_ring(struct protocol_stack *stack, struct lwip
 {
     bool replenish_again = false;
 
-    replenish_again = replenish_send_idlembuf(stack, sock->send_ring);
+    replenish_again = replenish_send_idlembuf(stack, sock);
 
     if ((sock->epoll_events & EPOLLOUT) && NETCONN_IS_OUTIDLE(sock)) {
         add_sock_event(sock, EPOLLOUT);
diff --git a/src/lstack/include/lstack_cfg.h b/src/lstack/include/lstack_cfg.h
index 6af081d..5f16c19 100644
--- a/src/lstack/include/lstack_cfg.h
+++ b/src/lstack/include/lstack_cfg.h
@@ -90,6 +90,7 @@ struct cfg_params {
     struct secondary_attach_arg sec_attach_arg;
     char unix_socket_filename[NAME_MAX];
     uint16_t send_ring_size;
+    bool expand_send_ring;
 };
 
 struct cfg_params *get_global_cfg_params(void);
diff --git a/src/lstack/lstack.conf b/src/lstack/lstack.conf
index fb68c32..a4571ff 100644
--- a/src/lstack/lstack.conf
+++ b/src/lstack/lstack.conf
@@ -22,6 +22,10 @@ mbuf_count_per_conn = 170
 
 # send ring size, default is 32, max is 2048
 send_ring_size = 256
+
+# 0: when send ring full, send return
+# 1: when send ring full, alloc mbuf from mempool to send data
+expand_send_ring = 0
  
 #protocol stack thread per loop params
 #send connect to nic
-- 
2.33.0