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bsps/arm: Avoid mbuf migration in LPC ethernet

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The receive task will only hand over a mbuf if it gets a new one
immediately.  This avoids mbuf migration out of the receive task in case
of overload.
This commit is contained in:
Sebastian Huber
2012-12-14 09:40:44 +01:00
parent c9562c593b
commit e5a7f8469a
1 changed files with 30 additions and 56 deletions
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86
c/src/lib/libbsp/arm/shared/lpc/network/lpc-ethernet.c
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@@ -7,7 +7,7 @@
*/
/*
* Copyright (c) 2009-2011 embedded brains GmbH. All rights reserved.
* Copyright (c) 2009-2012 embedded brains GmbH. All rights reserved.
*
* embedded brains GmbH
* Obere Lagerstr. 30
@@ -317,6 +317,7 @@ typedef struct {
unsigned receive_interrupts;
unsigned transmitted_frames;
unsigned transmit_interrupts;
unsigned receive_drop_errors;
unsigned receive_overrun_errors;
unsigned receive_fragment_errors;
unsigned receive_crc_errors;
@@ -528,14 +529,11 @@ static void lpc_eth_receive_task(void *arg)
uint32_t const index_max = e->rx_unit_count - 1;
uint32_t produce_index = 0;
uint32_t consume_index = 0;
uint32_t receive_index = 0;
LPC_ETH_PRINTF("%s\n", __func__);
/* Main event loop */
while (true) {
bool wait_for_mbuf = false;
/* Wait for events */
sc = rtems_bsdnet_event_receive(
LPC_ETH_EVENT_INITIALIZE | LPC_ETH_EVENT_INTERRUPT,
@@ -592,7 +590,6 @@ static void lpc_eth_receive_task(void *arg)
/* Initialize indices */
produce_index = lpc_eth->rxproduceindex;
consume_index = lpc_eth->rxconsumeindex;
receive_index = consume_index;
/* Enable receiver */
lpc_eth->command |= ETH_CMD_RX_ENABLE;
@@ -611,49 +608,47 @@ static void lpc_eth_receive_task(void *arg)
/* Get current produce index */
produce_index = lpc_eth->rxproduceindex;
if (receive_index != produce_index) {
if (consume_index != produce_index) {
uint32_t stat = 0;
/* Fragment mbuf */
struct mbuf *m = mbufs [receive_index];
/* Fragment status */
rtems_cache_invalidate_multiple_data_lines(
(void *) &status [receive_index],
(void *) &status [consume_index],
sizeof(status [0])
);
stat = status [receive_index].info;
/* Remove mbuf from table */
mbufs [receive_index] = NULL;
stat = status [consume_index].info;
if (
(stat & ETH_RX_STAT_LAST_FLAG) != 0
&& (stat & LPC_ETH_RX_STAT_ERRORS) == 0
) {
/* Ethernet header */
struct ether_header *eh = mtod(m, struct ether_header *);
/* Received mbuf */
struct mbuf *m = mbufs [consume_index];
/* Discard Ethernet header and CRC */
int sz = (int) (stat & ETH_RX_STAT_RXSIZE_MASK) + 1
- ETHER_HDR_LEN - ETHER_CRC_LEN;
if (lpc_eth_add_new_mbuf(ifp, desc, mbufs, consume_index, false)) {
/* Ethernet header */
struct ether_header *eh = mtod(m, struct ether_header *);
/* Update mbuf */
m->m_len = sz;
m->m_pkthdr.len = sz;
m->m_data = mtod(m, char *) + ETHER_HDR_LEN;
/* Discard Ethernet header and CRC */
int sz = (int) (stat & ETH_RX_STAT_RXSIZE_MASK) + 1
- ETHER_HDR_LEN - ETHER_CRC_LEN;
LPC_ETH_PRINTF("rx: %02" PRIu32 ": %u\n", receive_index, sz);
/* Update mbuf */
m->m_len = sz;
m->m_pkthdr.len = sz;
m->m_data = mtod(m, char *) + ETHER_HDR_LEN;
/* Hand over */
ether_input(ifp, eh, m);
LPC_ETH_PRINTF("rx: %02" PRIu32 ": %u\n", consume_index, sz);
/* Increment received frames counter */
++e->received_frames;
/* Hand over */
ether_input(ifp, eh, m);
/* Increment received frames counter */
++e->received_frames;
} else {
++e->receive_drop_errors;
}
} else {
/* Release mbuf */
m_free(m);
/* Update error counters */
if ((stat & ETH_RX_STAT_OVERRUN) != 0) {
++e->receive_overrun_errors;
@@ -678,37 +673,15 @@ static void lpc_eth_receive_task(void *arg)
}
}
/* Increment receive index */
receive_index = lpc_eth_increment(receive_index, index_max);
/* Increment and update consume index */
consume_index = lpc_eth_increment(consume_index, index_max);
lpc_eth->rxconsumeindex = consume_index;
} else {
/* Nothing to do, enable receive interrupts */
lpc_eth_enable_receive_interrupts();
break;
}
}
/* Wait for mbuf? */
wait_for_mbuf =
lpc_eth_increment(produce_index, index_max) == consume_index;
/* Fill queue with new mbufs */
while (consume_index != produce_index) {
/* Add new mbuf to queue */
if (
!lpc_eth_add_new_mbuf(ifp, desc, mbufs, consume_index, wait_for_mbuf)
) {
break;
}
/* We wait for at most one mbuf */
wait_for_mbuf = false;
/* Increment consume index */
consume_index = lpc_eth_increment(consume_index, index_max);
/* Update consume indices */
lpc_eth->rxconsumeindex = consume_index;
}
}
cleanup:
@@ -1268,6 +1241,7 @@ static void lpc_eth_interface_stats(lpc_eth_driver_entry *e)
printf("receive interrupts: %u\n", e->receive_interrupts);
printf("transmitted frames: %u\n", e->transmitted_frames);
printf("transmit interrupts: %u\n", e->transmit_interrupts);
printf("receive drop errors: %u\n", e->receive_drop_errors);
printf("receive overrun errors: %u\n", e->receive_overrun_errors);
printf("receive fragment errors: %u\n", e->receive_fragment_errors);
printf("receive CRC errors: %u\n", e->receive_crc_errors);