sfc: Report TX completions to BQL after all TX events in interrupt

The limit for BQL is updated each time we call
netdev_tx_completed_queue.
Without this patch the BQL limit was updated for every TX event we
see.
The issue was that this only updated the limit to handle the data
we complete in two events as the first event wouldn't show that
enough traffic had been processed between them.

This was OK when interrupt moderation was off but not when it was
on as more data had to be completed in a single interrupt.

The patch changes this so that we do report the completion to BQL
only when all the TX events in the interrupt have been processed.

Signed-off-by: Shradha Shah <sshah@solarflare.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/drivers/net/ethernet/sfc/efx.c b/drivers/net/ethernet/sfc/efx.c
index 804b9ad553d3841b076d4f3e8ee6ba627396226f..03bc03b67f08b3224f6e0d13b1fc0c189780c1af 100644 (file)
--- a/drivers/net/ethernet/sfc/efx.c
+++ b/drivers/net/ethernet/sfc/efx.c
@@ -245,11 +245,17 @@ static int efx_check_disabled(struct efx_nic *efx)
  */
 static int efx_process_channel(struct efx_channel *channel, int budget)
 {
+       struct efx_tx_queue *tx_queue;
        int spent;
 
        if (unlikely(!channel->enabled))
                return 0;
 
+       efx_for_each_channel_tx_queue(tx_queue, channel) {
+               tx_queue->pkts_compl = 0;
+               tx_queue->bytes_compl = 0;
+       }
+
        spent = efx_nic_process_eventq(channel, budget);
        if (spent && efx_channel_has_rx_queue(channel)) {
                struct efx_rx_queue *rx_queue =
@@ -259,6 +265,14 @@ static int efx_process_channel(struct efx_channel *channel, int budget)
                efx_fast_push_rx_descriptors(rx_queue, true);
        }
 
+       /* Update BQL */
+       efx_for_each_channel_tx_queue(tx_queue, channel) {
+               if (tx_queue->bytes_compl) {
+                       netdev_tx_completed_queue(tx_queue->core_txq,
+                               tx_queue->pkts_compl, tx_queue->bytes_compl);
+               }
+       }
+
        return spent;
 }
 

diff --git a/drivers/net/ethernet/sfc/net_driver.h b/drivers/net/ethernet/sfc/net_driver.h
index d72f522bf9c3b2c0d9df322a7798ec1be6a1aba8..47d1e3a96522668a1cf1c80cacd141d2afbf1193 100644 (file)
--- a/drivers/net/ethernet/sfc/net_driver.h
+++ b/drivers/net/ethernet/sfc/net_driver.h
@@ -241,6 +241,8 @@ struct efx_tx_queue {
        unsigned int read_count ____cacheline_aligned_in_smp;
        unsigned int old_write_count;
        unsigned int merge_events;
+       unsigned int bytes_compl;
+       unsigned int pkts_compl;
 
        /* Members used only on the xmit path */
        unsigned int insert_count ____cacheline_aligned_in_smp;

diff --git a/drivers/net/ethernet/sfc/tx.c b/drivers/net/ethernet/sfc/tx.c
index aaf2987512b5db7472bdef518c4aa4c510612ef7..1833a01465711d56d1b2e09b03090792929d3a1b 100644 (file)
--- a/drivers/net/ethernet/sfc/tx.c
+++ b/drivers/net/ethernet/sfc/tx.c
@@ -617,7 +617,8 @@ void efx_xmit_done(struct efx_tx_queue *tx_queue, unsigned int index)
        EFX_BUG_ON_PARANOID(index > tx_queue->ptr_mask);
 
        efx_dequeue_buffers(tx_queue, index, &pkts_compl, &bytes_compl);
-       netdev_tx_completed_queue(tx_queue->core_txq, pkts_compl, bytes_compl);
+       tx_queue->pkts_compl += pkts_compl;
+       tx_queue->bytes_compl += bytes_compl;
 
        if (pkts_compl > 1)
                ++tx_queue->merge_events;