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Bluetooth: h4: Use k_fifo instead of k_sem

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So far the use of k_sem meant that there was no major benefit of
having more than 2 or 3 RX buffers since there was no queuing
mechanism. Instead of using k_sem, introduce a k_fifo and use that to
queue up incoming buffers. This way the RX buffer count can be
increased with measurable effects on throughput.

Change-Id: I8122b233aeee7c8e145de3fff5f10bcfe348efaa
Signed-off-by: Johan Hedberg <johan.hedberg@intel.com>
This commit is contained in:
Johan Hedberg 2016-12-31 14:41:45 +02:00
commit 37aa1a1f8b
1 changed files with 67 additions and 48 deletions
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115
drivers/bluetooth/hci/h4.c
View file

@ -54,7 +54,7 @@ static BT_STACK_NOINIT(rx_thread_stack, CONFIG_BLUETOOTH_RX_STACK_SIZE);
static struct {
struct net_buf *buf;
struct k_sem sem;
struct k_fifo fifo;
uint16_t remaining;
uint16_t discard;
@ -67,7 +67,7 @@ static struct {
struct bt_hci_acl_hdr acl;
};
} rx = {
.sem = K_SEM_INITIALIZER(rx.sem, 0, 1),
.fifo = K_FIFO_INITIALIZER(rx.fifo),
};
static struct device *h4_dev;
@ -102,8 +102,8 @@ static inline void get_acl_hdr(void)
rx.remaining -= uart_fifo_read(h4_dev, (uint8_t *)hdr + to_read,
rx.remaining);
if (!rx.remaining) {
BT_DBG("Got ACL header");
rx.remaining = sys_le16_to_cpu(hdr->len);
BT_DBG("Got ACL header. Payload %u bytes", rx.remaining);
rx.have_hdr = true;
}
}
@ -116,28 +116,21 @@ static inline void get_evt_hdr(void)
rx.remaining -= uart_fifo_read(h4_dev, (uint8_t *)hdr + to_read,
rx.remaining);
if (!rx.remaining) {
BT_DBG("Got event header");
rx.remaining = hdr->len;
BT_DBG("Got event header. Payload %u bytes", rx.remaining);
rx.have_hdr = true;
}
}
static inline void buf_set_type(struct net_buf *buf)
{
if (rx.type == H4_EVT) {
bt_buf_set_type(buf, BT_BUF_EVT);
} else {
bt_buf_set_type(buf, BT_BUF_ACL_IN);
}
}
static inline void copy_hdr(struct net_buf *buf)
{
if (rx.type == H4_EVT) {
net_buf_add_mem(buf, &rx.evt, sizeof(rx.evt));
BT_DBG("buf %p EVT len %u", buf, sys_le16_to_cpu(rx.evt.len));
} else {
net_buf_add_mem(buf, &rx.acl, sizeof(rx.acl));
BT_DBG("buf %p ACL len %u", buf, sys_le16_to_cpu(rx.acl.len));
}
}
@ -152,34 +145,40 @@ static void rx_thread(void *p1, void *p2, void *p3)
BT_DBG("started");
while (1) {
BT_DBG("waiting for semaphore");
k_sem_take(&rx.sem, K_FOREVER);
BT_DBG("got semaphore, rx.buf %p have_hdr %u",
rx.buf, rx.have_hdr);
BT_DBG("rx.buf %p", rx.buf);
if (rx.buf) {
buf = rx.buf;
buf_set_type(buf);
rx.buf = NULL;
rx.have_hdr = false;
rx.type = H4_NONE;
uart_irq_rx_enable(h4_dev);
BT_DBG("Calling bt_recv()");
bt_recv(buf);
} else {
if (!rx.buf) {
rx.buf = bt_buf_get_rx(K_FOREVER);
BT_DBG("Got rx.buf %p", rx.buf);
if (rx.remaining > net_buf_tailroom(rx.buf)) {
BT_ERR("Not enough space in buffer");
rx.discard = rx.remaining;
rx.remaining = 0;
rx.have_hdr = 0;
} else {
rx.have_hdr = false;
} else if (rx.have_hdr) {
copy_hdr(rx.buf);
}
uart_irq_rx_enable(h4_dev);
}
/* Let the ISR continue receiving new packets */
uart_irq_rx_enable(h4_dev);
buf = net_buf_get(&rx.fifo, K_FOREVER);
do {
uart_irq_rx_enable(h4_dev);
BT_DBG("Calling bt_recv(%p)", buf);
bt_recv(buf);
/* Give other threads a chance to run if the ISR
* is receiving data so fast that rx.fifo never
* or very rarely goes empty.
*/
k_yield();
uart_irq_rx_disable(h4_dev);
buf = net_buf_get(&rx.fifo, K_NO_WAIT);
} while (buf);
}
}
@ -193,17 +192,28 @@ static size_t h4_discard(struct device *uart, size_t len)
/* Returns false if RX IRQ was disabled and control given to the RX thread */
static inline bool read_payload(void)
{
struct net_buf *buf;
bool prio;
int read;
if (!rx.buf) {
rx.buf = bt_buf_get_rx(K_NO_WAIT);
if (!rx.buf) {
BT_DBG("Failed to allocate, deferring to rx_thread");
uart_irq_rx_disable(h4_dev);
BT_DBG("giving semaphore");
k_sem_give(&rx.sem);
return false;
}
BT_DBG("Allocated rx.buf %p", rx.buf);
if (rx.remaining > net_buf_tailroom(rx.buf)) {
BT_ERR("Not enough space in buffer");
rx.discard = rx.remaining;
rx.remaining = 0;
rx.have_hdr = false;
return true;
}
copy_hdr(rx.buf);
}
@ -219,19 +229,29 @@ static inline bool read_payload(void)
return true;
}
if (rx.type == H4_EVT && bt_hci_evt_is_prio(rx.evt.evt)) {
buf_set_type(rx.buf);
BT_DBG("Calling bt_recv()");
bt_recv(rx.buf);
rx.buf = NULL;
rx.have_hdr = false;
rx.type = H4_NONE;
return true;
prio = (rx.type == H4_EVT && bt_hci_evt_is_prio(rx.evt.evt));
buf = rx.buf;
rx.buf = NULL;
if (rx.type == H4_EVT) {
bt_buf_set_type(buf, BT_BUF_EVT);
} else {
uart_irq_rx_disable(h4_dev);
k_sem_give(&rx.sem);
return false;
bt_buf_set_type(buf, BT_BUF_ACL_IN);
}
rx.type = H4_NONE;
rx.have_hdr = false;
if (prio) {
BT_DBG("Calling bt_recv(%p)", buf);
bt_recv(buf);
} else {
BT_DBG("Putting buf %p to rx fifo", buf);
net_buf_put(&rx.fifo, buf);
}
return true;
}
static inline void read_header(void)
@ -256,7 +276,7 @@ static inline void read_header(void)
BT_ERR("Not enough space in buffer");
rx.discard = rx.remaining;
rx.remaining = 0;
rx.have_hdr = 0;
rx.have_hdr = false;
} else {
copy_hdr(rx.buf);
}
@ -292,6 +312,7 @@ static void bt_uart_isr(struct device *unused)
continue;
}
/* Returns false if RX interrupt was disabled */
if (!read_payload()) {
return;
}
@ -339,8 +360,6 @@ static int h4_open(void)
uart_irq_callback_set(h4_dev, bt_uart_isr);
uart_irq_rx_enable(h4_dev);
k_thread_spawn(rx_thread_stack, sizeof(rx_thread_stack), rx_thread,
NULL, NULL, NULL, K_PRIO_COOP(7), 0, K_NO_WAIT);