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Add additional doorbells on ENA Tx path

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The new ENA HAL is introducing API, which can determine on Tx path if
the doorbell is needed.

That way, it can tell the driver, that it should call an doorbell.
The old threshold value wasn't removed, as not all HW is supporting this
feature - so it was reworked to also work with the new API.

Submitted by:  Michal Krawczyk <mk@semihalf.com>
Obtained from: Semihalf
Sponsored by:  Amazon, Inc.
This commit is contained in:
Marcin Wojtas 2019-05-30 13:33:31 +00:00
parent 82f5a7921c
commit af66d7d029
2 changed files with 19 additions and 12 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

28
sys/dev/ena/ena.c
View File

@ -590,6 +590,7 @@ ena_setup_tx_resources(struct ena_adapter *adapter, int qid)
tx_ring->next_to_use = 0;
tx_ring->next_to_clean = 0;
tx_ring->acum_pkts = 0;
/* Make sure that drbr is empty */
ENA_RING_MTX_LOCK(tx_ring);
@ -3007,6 +3008,18 @@ ena_xmit_mbuf(struct ena_ring *tx_ring, struct mbuf **mbuf)
/* Set flags and meta data */
ena_tx_csum(&ena_tx_ctx, *mbuf);
if (tx_ring->acum_pkts == DB_THRESHOLD ||
ena_com_is_doorbell_needed(tx_ring->ena_com_io_sq, &ena_tx_ctx)) {
ena_trace(ENA_DBG | ENA_TXPTH,
"llq tx max burst size of queue %d achieved, writing doorbell to send burst\n",
tx_ring->que->id);
wmb();
ena_com_write_sq_doorbell(tx_ring->ena_com_io_sq);
counter_u64_add(tx_ring->tx_stats.doorbells, 1);
tx_ring->acum_pkts = 0;
}
/* Prepare the packet's descriptors and send them to device */
rc = ena_com_prepare_tx(io_sq, &ena_tx_ctx, &nb_hw_desc);
if (unlikely(rc != 0)) {
@ -3096,7 +3109,6 @@ ena_start_xmit(struct ena_ring *tx_ring)
struct ena_adapter *adapter = tx_ring->adapter;
struct ena_com_io_sq* io_sq;
int ena_qid;
int acum_pkts = 0;
int ret = 0;
if (unlikely((if_getdrvflags(adapter->ifp) & IFF_DRV_RUNNING) == 0))
@ -3137,25 +3149,17 @@ ena_start_xmit(struct ena_ring *tx_ring)
IFF_DRV_RUNNING) == 0))
return;
acum_pkts++;
tx_ring->acum_pkts++;
BPF_MTAP(adapter->ifp, mbuf);
if (unlikely(acum_pkts == DB_THRESHOLD)) {
acum_pkts = 0;
wmb();
/* Trigger the dma engine */
ena_com_write_sq_doorbell(io_sq);
counter_u64_add(tx_ring->tx_stats.doorbells, 1);
}
}
if (likely(acum_pkts != 0)) {
if (likely(tx_ring->acum_pkts != 0)) {
wmb();
/* Trigger the dma engine */
ena_com_write_sq_doorbell(io_sq);
counter_u64_add(tx_ring->tx_stats.doorbells, 1);
tx_ring->acum_pkts = 0;
}
if (unlikely(!tx_ring->running))

3
sys/dev/ena/ena.h
View File

@ -319,6 +319,9 @@ struct ena_ring {
bool running;
};
/* How many packets are sent in one Tx loop, used for doorbells */
uint32_t acum_pkts;
/* Used for LLQ */
uint8_t *push_buf_intermediate_buf;
} __aligned(CACHE_LINE_SIZE);