[Intel-wired-lan] [RFC PATCH] i40e: enable PCIe relax ordering for SPARC
tndave
tushar.n.dave at oracle.com
Mon Dec 5 22:23:59 UTC 2016
On 12/05/2016 01:54 PM, Alexander Duyck wrote:
> On Mon, Dec 5, 2016 at 9:07 AM, Tushar Dave <tushar.n.dave at oracle.com> wrote:
>> Unlike previous generation NIC (e.g. ixgbe) i40e doesn't seem to have
>> standard CSR where PCIe relaxed ordering can be set. Without PCIe relax
>> ordering enabled, i40e performance is significantly low on SPARC.
>>
>> This patch sets PCIe relax ordering for SPARC arch by setting dma attr
>> DMA_ATTR_WEAK_ORDERING for every tx and rx DMA map/unmap.
>> This has shown 10x increase in performance numbers.
>>
>> e.g.
>> iperf TCP test with 10 threads on SPARC S7
>>
>> Test 1: Without this patch
>>
>> # iperf -s
>> ------------------------------------------------------------
>> Server listening on TCP port 5001
>> TCP window size: 85.3 KByte (default)
>> ------------------------------------------------------------
>> [ 4] local 16.0.0.7 port 5001 connected with 16.0.0.1 port 40926
>> [ 5] local 16.0.0.7 port 5001 connected with 16.0.0.1 port 40934
>> [ 6] local 16.0.0.7 port 5001 connected with 16.0.0.1 port 40930
>> [ 7] local 16.0.0.7 port 5001 connected with 16.0.0.1 port 40928
>> [ 8] local 16.0.0.7 port 5001 connected with 16.0.0.1 port 40922
>> [ 9] local 16.0.0.7 port 5001 connected with 16.0.0.1 port 40932
>> [ 10] local 16.0.0.7 port 5001 connected with 16.0.0.1 port 40920
>> [ 11] local 16.0.0.7 port 5001 connected with 16.0.0.1 port 40924
>> [ 14] local 16.0.0.7 port 5001 connected with 16.0.0.1 port 40982
>> [ 12] local 16.0.0.7 port 5001 connected with 16.0.0.1 port 40980
>> [ ID] Interval Transfer Bandwidth
>> [ 4] 0.0-20.0 sec 566 MBytes 237 Mbits/sec
>> [ 5] 0.0-20.0 sec 532 MBytes 223 Mbits/sec
>> [ 6] 0.0-20.0 sec 537 MBytes 225 Mbits/sec
>> [ 8] 0.0-20.0 sec 546 MBytes 229 Mbits/sec
>> [ 11] 0.0-20.0 sec 592 MBytes 248 Mbits/sec
>> [ 7] 0.0-20.0 sec 539 MBytes 226 Mbits/sec
>> [ 9] 0.0-20.0 sec 572 MBytes 240 Mbits/sec
>> [ 10] 0.0-20.0 sec 604 MBytes 253 Mbits/sec
>> [ 14] 0.0-20.0 sec 567 MBytes 238 Mbits/sec
>> [ 12] 0.0-20.0 sec 511 MBytes 214 Mbits/sec
>> [SUM] 0.0-20.0 sec 5.44 GBytes 2.33 Gbits/sec
>>
>> Test 2: with this patch:
>>
>> # iperf -s
>> ------------------------------------------------------------
>> Server listening on TCP port 5001
>> TCP window size: 85.3 KByte (default)
>> ------------------------------------------------------------
>> TCP: request_sock_TCP: Possible SYN flooding on port 5001. Sending
>> cookies. Check SNMP counters.
>> [ 4] local 16.0.0.7 port 5001 connected with 16.0.0.1 port 46876
>> [ 5] local 16.0.0.7 port 5001 connected with 16.0.0.1 port 46874
>> [ 6] local 16.0.0.7 port 5001 connected with 16.0.0.1 port 46872
>> [ 7] local 16.0.0.7 port 5001 connected with 16.0.0.1 port 46880
>> [ 8] local 16.0.0.7 port 5001 connected with 16.0.0.1 port 46878
>> [ 9] local 16.0.0.7 port 5001 connected with 16.0.0.1 port 46884
>> [ 10] local 16.0.0.7 port 5001 connected with 16.0.0.1 port 46886
>> [ 11] local 16.0.0.7 port 5001 connected with 16.0.0.1 port 46890
>> [ 12] local 16.0.0.7 port 5001 connected with 16.0.0.1 port 46888
>> [ 13] local 16.0.0.7 port 5001 connected with 16.0.0.1 port 46882
>> [ ID] Interval Transfer Bandwidth
>> [ 4] 0.0-20.0 sec 7.45 GBytes 3.19 Gbits/sec
>> [ 5] 0.0-20.0 sec 7.48 GBytes 3.21 Gbits/sec
>> [ 7] 0.0-20.0 sec 7.34 GBytes 3.15 Gbits/sec
>> [ 8] 0.0-20.0 sec 7.42 GBytes 3.18 Gbits/sec
>> [ 9] 0.0-20.0 sec 7.24 GBytes 3.11 Gbits/sec
>> [ 10] 0.0-20.0 sec 7.40 GBytes 3.17 Gbits/sec
>> [ 12] 0.0-20.0 sec 7.49 GBytes 3.21 Gbits/sec
>> [ 6] 0.0-20.0 sec 7.30 GBytes 3.13 Gbits/sec
>> [ 11] 0.0-20.0 sec 7.44 GBytes 3.19 Gbits/sec
>> [ 13] 0.0-20.0 sec 7.22 GBytes 3.10 Gbits/sec
>> [SUM] 0.0-20.0 sec 73.8 GBytes 31.6 Gbits/sec
>>
>> NOTE: In my testing, this patch does _not_ show any harm to i40e
>> performance numbers on x86.
>>
>> Signed-off-by: Tushar Dave <tushar.n.dave at oracle.com>
>
> You went through and replaced all of the dma_unmap/map_page calls with
> dma_map/unmap_single_attrs I would prefer you didn't do that. I have
Yes, because currently there is no DMA API for dma_map/unmap_page with
dma attr*
> patches to add the ability to map and unmap pages with attributes that
> should be available for 4.10-rc1 so if you could wait on this patch
> until then it would be preferred.
:-) thanks. I will wait until your patches are out.
>
>> ---
>> drivers/net/ethernet/intel/i40e/i40e_txrx.c | 69 ++++++++++++++++++++---------
>> drivers/net/ethernet/intel/i40e/i40e_txrx.h | 1 +
>> 2 files changed, 49 insertions(+), 21 deletions(-)
>>
>> diff --git a/drivers/net/ethernet/intel/i40e/i40e_txrx.c b/drivers/net/ethernet/intel/i40e/i40e_txrx.c
>> index 6287bf6..800dca7 100644
>> --- a/drivers/net/ethernet/intel/i40e/i40e_txrx.c
>> +++ b/drivers/net/ethernet/intel/i40e/i40e_txrx.c
>> @@ -551,15 +551,17 @@ static void i40e_unmap_and_free_tx_resource(struct i40e_ring *ring,
>> else
>> dev_kfree_skb_any(tx_buffer->skb);
>> if (dma_unmap_len(tx_buffer, len))
>> - dma_unmap_single(ring->dev,
>> - dma_unmap_addr(tx_buffer, dma),
>> - dma_unmap_len(tx_buffer, len),
>> - DMA_TO_DEVICE);
>> + dma_unmap_single_attrs(ring->dev,
>> + dma_unmap_addr(tx_buffer, dma),
>> + dma_unmap_len(tx_buffer, len),
>> + DMA_TO_DEVICE,
>> + ring->dma_attrs);
>> } else if (dma_unmap_len(tx_buffer, len)) {
>> - dma_unmap_page(ring->dev,
>> - dma_unmap_addr(tx_buffer, dma),
>> - dma_unmap_len(tx_buffer, len),
>> - DMA_TO_DEVICE);
>> + dma_unmap_single_attrs(ring->dev,
>> + dma_unmap_addr(tx_buffer, dma),
>> + dma_unmap_len(tx_buffer, len),
>> + DMA_TO_DEVICE,
>> + ring->dma_attrs);
>> }
>>
>> tx_buffer->next_to_watch = NULL;
>> @@ -662,6 +664,8 @@ static bool i40e_clean_tx_irq(struct i40e_vsi *vsi,
>> struct i40e_tx_buffer *tx_buf;
>> struct i40e_tx_desc *tx_head;
>> struct i40e_tx_desc *tx_desc;
>> + dma_addr_t addr;
>> + size_t size;
>> unsigned int total_bytes = 0, total_packets = 0;
>> unsigned int budget = vsi->work_limit;
>>
>> @@ -696,10 +700,11 @@ static bool i40e_clean_tx_irq(struct i40e_vsi *vsi,
>> napi_consume_skb(tx_buf->skb, napi_budget);
>>
>> /* unmap skb header data */
>> - dma_unmap_single(tx_ring->dev,
>> - dma_unmap_addr(tx_buf, dma),
>> - dma_unmap_len(tx_buf, len),
>> - DMA_TO_DEVICE);
>> + dma_unmap_single_attrs(tx_ring->dev,
>> + dma_unmap_addr(tx_buf, dma),
>> + dma_unmap_len(tx_buf, len),
>> + DMA_TO_DEVICE,
>> + tx_ring->dma_attrs);
>>
>> /* clear tx_buffer data */
>> tx_buf->skb = NULL;
>> @@ -717,12 +722,15 @@ static bool i40e_clean_tx_irq(struct i40e_vsi *vsi,
>> tx_desc = I40E_TX_DESC(tx_ring, 0);
>> }
>>
>> + addr = dma_unmap_addr(tx_buf, dma);
>> + size = dma_unmap_len(tx_buf, len);
>
> On some architectures this change could lead to issues since
> dma_unmap_len could be 0 meaning that addr would never be used.
I see. Thanks.
>
>> /* unmap any remaining paged data */
>> if (dma_unmap_len(tx_buf, len)) {
>> - dma_unmap_page(tx_ring->dev,
>> - dma_unmap_addr(tx_buf, dma),
>> - dma_unmap_len(tx_buf, len),
>> - DMA_TO_DEVICE);
>> + dma_unmap_single_attrs(tx_ring->dev,
>> + addr,
>> + size,
>> + DMA_TO_DEVICE,
>> + tx_ring->dma_attrs);
>> dma_unmap_len_set(tx_buf, len, 0);
>> }
>> }
>> @@ -1010,6 +1018,11 @@ int i40e_setup_tx_descriptors(struct i40e_ring *tx_ring)
>> */
>> tx_ring->size += sizeof(u32);
>> tx_ring->size = ALIGN(tx_ring->size, 4096);
>> +#ifdef CONFIG_SPARC
>> + tx_ring->dma_attrs = DMA_ATTR_WEAK_ORDERING;
>> +#else
>> + tx_ring->dma_attrs = 0;
>> +#endif
>> tx_ring->desc = dma_alloc_coherent(dev, tx_ring->size,
>> &tx_ring->dma, GFP_KERNEL);
>> if (!tx_ring->desc) {
>
> Also not a fan of adding yet ring attribute. Is there any reason why
> you couldn't simply add a set of inline functions at the start of
> i40e_txrx.c that could replace the DMA map/unmap operations in this
> code but pass either 0 or DMA_ATTR_WEAK_ORDERING as needed for the
> drivers? Then the x86 code doesn't have to change while the SPARC
> code will be able to be passed the attribute.
Sure I can do that.
I will follow up with patch after your patches for map/unmap page with
dma attr will be out.
Thanks.
-Tushar
>
>> @@ -1053,7 +1066,11 @@ void i40e_clean_rx_ring(struct i40e_ring *rx_ring)
>> if (!rx_bi->page)
>> continue;
>>
>> - dma_unmap_page(dev, rx_bi->dma, PAGE_SIZE, DMA_FROM_DEVICE);
>> + dma_unmap_single_attrs(dev,
>> + rx_bi->dma,
>> + PAGE_SIZE,
>> + DMA_FROM_DEVICE,
>> + rx_ring->dma_attrs);
>> __free_pages(rx_bi->page, 0);
>>
>> rx_bi->page = NULL;
>> @@ -1113,6 +1130,11 @@ int i40e_setup_rx_descriptors(struct i40e_ring *rx_ring)
>> /* Round up to nearest 4K */
>> rx_ring->size = rx_ring->count * sizeof(union i40e_32byte_rx_desc);
>> rx_ring->size = ALIGN(rx_ring->size, 4096);
>> +#ifdef CONFIG_SPARC
>> + rx_ring->dma_attrs = DMA_ATTR_WEAK_ORDERING;
>> +#else
>> + rx_ring->dma_attrs = 0;
>> +#endif
>> rx_ring->desc = dma_alloc_coherent(dev, rx_ring->size,
>> &rx_ring->dma, GFP_KERNEL);
>>
>> @@ -1182,7 +1204,8 @@ static bool i40e_alloc_mapped_page(struct i40e_ring *rx_ring,
>> }
>>
>> /* map page for use */
>> - dma = dma_map_page(rx_ring->dev, page, 0, PAGE_SIZE, DMA_FROM_DEVICE);
>> + dma = dma_map_single_attrs(rx_ring->dev, page_address(page), PAGE_SIZE,
>> + DMA_FROM_DEVICE, rx_ring->dma_attrs);
>>
>> /* if mapping failed free memory back to system since
>> * there isn't much point in holding memory we can't use
>> @@ -1695,8 +1718,11 @@ struct sk_buff *i40e_fetch_rx_buffer(struct i40e_ring *rx_ring,
>> rx_ring->rx_stats.page_reuse_count++;
>> } else {
>> /* we are not reusing the buffer so unmap it */
>> - dma_unmap_page(rx_ring->dev, rx_buffer->dma, PAGE_SIZE,
>> - DMA_FROM_DEVICE);
>> + dma_unmap_single_attrs(rx_ring->dev,
>> + rx_buffer->dma,
>> + PAGE_SIZE,
>> + DMA_FROM_DEVICE,
>> + rx_ring->dma_attrs);
>> }
>>
>> /* clear contents of buffer_info */
>> @@ -2737,7 +2763,8 @@ static inline void i40e_tx_map(struct i40e_ring *tx_ring, struct sk_buff *skb,
>> first->skb = skb;
>> first->tx_flags = tx_flags;
>>
>> - dma = dma_map_single(tx_ring->dev, skb->data, size, DMA_TO_DEVICE);
>> + dma = dma_map_single_attrs(tx_ring->dev, skb->data, size,
>> + DMA_TO_DEVICE, tx_ring->dma_attrs);
>>
>> tx_desc = I40E_TX_DESC(tx_ring, i);
>> tx_bi = first;
>> diff --git a/drivers/net/ethernet/intel/i40e/i40e_txrx.h b/drivers/net/ethernet/intel/i40e/i40e_txrx.h
>> index 5088405..9a86212 100644
>> --- a/drivers/net/ethernet/intel/i40e/i40e_txrx.h
>> +++ b/drivers/net/ethernet/intel/i40e/i40e_txrx.h
>> @@ -327,6 +327,7 @@ struct i40e_ring {
>>
>> unsigned int size; /* length of descriptor ring in bytes */
>> dma_addr_t dma; /* physical address of ring */
>> + unsigned long dma_attrs; /* DMA attributes */
>>
>> struct i40e_vsi *vsi; /* Backreference to associated VSI */
>> struct i40e_q_vector *q_vector; /* Backreference to associated vector */
>> --
>> 1.9.1
>>
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