diff options
| author | David Riddoch <driddoch@solarflare.com> | 2012-04-11 13:12:41 +0100 |
|---|---|---|
| committer | Ben Hutchings <bhutchings@solarflare.com> | 2012-05-10 02:22:17 +0100 |
| commit | 64235187c2b32913fc41dfafc98e3a77ea7c0217 (patch) | |
| tree | 4d2faf81428d4c5c3741823c0c5700a39f80db4a | |
| parent | da9ca505829f6c270b239536b1b169644d7cf072 (diff) | |
| download | blackbird-op-linux-64235187c2b32913fc41dfafc98e3a77ea7c0217.tar.gz blackbird-op-linux-64235187c2b32913fc41dfafc98e3a77ea7c0217.zip | |
sfc: By default refill RX rings as soon as space for a batch
Previously we refilled with much larger batches, which caused large latency
spikes. We now have many more much much smaller spikes!
Signed-off-by: Ben Hutchings <bhutchings@solarflare.com>
| -rw-r--r-- | drivers/net/ethernet/sfc/rx.c | 18 |
1 files changed, 12 insertions, 6 deletions
diff --git a/drivers/net/ethernet/sfc/rx.c b/drivers/net/ethernet/sfc/rx.c index 254fec81894e..243e91f3dff9 100644 --- a/drivers/net/ethernet/sfc/rx.c +++ b/drivers/net/ethernet/sfc/rx.c @@ -76,7 +76,7 @@ static int rx_alloc_method = RX_ALLOC_METHOD_AUTO; /* This is the percentage fill level below which new RX descriptors * will be added to the RX descriptor ring. */ -static unsigned int rx_refill_threshold = 90; +static unsigned int rx_refill_threshold; /* * RX maximum head room required. @@ -363,8 +363,7 @@ void efx_fast_push_rx_descriptors(struct efx_rx_queue *rx_queue) } space = rx_queue->max_fill - fill_level; - if (space < EFX_RX_BATCH) - goto out; + EFX_BUG_ON_PARANOID(space < EFX_RX_BATCH); netif_vdbg(rx_queue->efx, rx_status, rx_queue->efx->net_dev, "RX queue %d fast-filling descriptor ring from" @@ -676,7 +675,7 @@ int efx_probe_rx_queue(struct efx_rx_queue *rx_queue) void efx_init_rx_queue(struct efx_rx_queue *rx_queue) { struct efx_nic *efx = rx_queue->efx; - unsigned int max_fill, trigger; + unsigned int max_fill, trigger, max_trigger; netif_dbg(rx_queue->efx, drv, rx_queue->efx->net_dev, "initialising RX queue %d\n", efx_rx_queue_index(rx_queue)); @@ -689,7 +688,14 @@ void efx_init_rx_queue(struct efx_rx_queue *rx_queue) /* Initialise limit fields */ max_fill = efx->rxq_entries - EFX_RXD_HEAD_ROOM; - trigger = max_fill * min(rx_refill_threshold, 100U) / 100U; + max_trigger = max_fill - EFX_RX_BATCH; + if (rx_refill_threshold != 0) { + trigger = max_fill * min(rx_refill_threshold, 100U) / 100U; + if (trigger > max_trigger) + trigger = max_trigger; + } else { + trigger = max_trigger; + } rx_queue->max_fill = max_fill; rx_queue->fast_fill_trigger = trigger; @@ -739,5 +745,5 @@ MODULE_PARM_DESC(rx_alloc_method, "Allocation method used for RX buffers"); module_param(rx_refill_threshold, uint, 0444); MODULE_PARM_DESC(rx_refill_threshold, - "RX descriptor ring fast/slow fill threshold (%)"); + "RX descriptor ring refill threshold (%)"); |
