[PATCH iwl-next 05/12] idpf: strictly assert cachelines of queue and queue vector structures
From: Alexander Lobakin
Date: Tue May 28 2024 - 09:50:48 EST
Now that the queue and queue vector structures are separated and laid
out optimally, group the fields as read-mostly, read-write, and cold
cachelines and add size assertions to make sure new features won't push
something out of its place and provoke perf regression.
Despite looking innocent, this gives up to 2% of perf bump on Rx.
Reviewed-by: Przemek Kitszel <przemyslaw.kitszel@xxxxxxxxx>
Signed-off-by: Alexander Lobakin <aleksander.lobakin@xxxxxxxxx>
---
drivers/net/ethernet/intel/idpf/idpf_txrx.h | 443 +++++++++++---------
1 file changed, 250 insertions(+), 193 deletions(-)
diff --git a/drivers/net/ethernet/intel/idpf/idpf_txrx.h b/drivers/net/ethernet/intel/idpf/idpf_txrx.h
index 9e4ba0aaf3ab..731e2a73def5 100644
--- a/drivers/net/ethernet/intel/idpf/idpf_txrx.h
+++ b/drivers/net/ethernet/intel/idpf/idpf_txrx.h
@@ -6,6 +6,7 @@
#include <linux/dim.h>
+#include <net/libeth/cache.h>
#include <net/page_pool/helpers.h>
#include <net/tcp.h>
#include <net/netdev_queues.h>
@@ -504,59 +505,70 @@ struct idpf_intr_reg {
/**
* struct idpf_q_vector
+ * @read_mostly: CL group with rarely written hot fields
* @vport: Vport back pointer
- * @napi: napi handler
- * @v_idx: Vector index
- * @intr_reg: See struct idpf_intr_reg
+ * @num_rxq: Number of RX queues
* @num_txq: Number of TX queues
+ * @num_bufq: Number of buffer queues
* @num_complq: number of completion queues
+ * @rx: Array of RX queues to service
* @tx: Array of TX queues to service
+ * @bufq: Array of buffer queues to service
* @complq: array of completion queues
+ * @intr_reg: See struct idpf_intr_reg
+ * @read_write: CL group with both read/write hot fields
+ * @napi: napi handler
+ * @total_events: Number of interrupts processed
* @tx_dim: Data for TX net_dim algorithm
* @tx_itr_value: TX interrupt throttling rate
* @tx_intr_mode: Dynamic ITR or not
* @tx_itr_idx: TX ITR index
- * @num_rxq: Number of RX queues
- * @rx: Array of RX queues to service
* @rx_dim: Data for RX net_dim algorithm
* @rx_itr_value: RX interrupt throttling rate
* @rx_intr_mode: Dynamic ITR or not
* @rx_itr_idx: RX ITR index
- * @num_bufq: Number of buffer queues
- * @bufq: Array of buffer queues to service
- * @total_events: Number of interrupts processed
+ * @cold: CL group with fields no touched on hotpath
+ * @v_idx: Vector index
* @affinity_mask: CPU affinity mask
*/
struct idpf_q_vector {
- struct idpf_vport *vport;
- struct napi_struct napi;
- u16 v_idx;
- struct idpf_intr_reg intr_reg;
-
- u16 num_txq;
- u16 num_complq;
- struct idpf_tx_queue **tx;
- struct idpf_compl_queue **complq;
-
- struct dim tx_dim;
- u16 tx_itr_value;
- bool tx_intr_mode;
- u32 tx_itr_idx;
-
- u16 num_rxq;
- struct idpf_rx_queue **rx;
- struct dim rx_dim;
- u16 rx_itr_value;
- bool rx_intr_mode;
- u32 rx_itr_idx;
-
- u16 num_bufq;
- struct idpf_buf_queue **bufq;
-
- u16 total_events;
-
- cpumask_var_t affinity_mask;
+ libeth_cacheline_group(read_mostly,
+ struct idpf_vport *vport;
+
+ u16 num_rxq;
+ u16 num_txq;
+ u16 num_bufq;
+ u16 num_complq;
+ struct idpf_rx_queue **rx;
+ struct idpf_tx_queue **tx;
+ struct idpf_buf_queue **bufq;
+ struct idpf_compl_queue **complq;
+
+ struct idpf_intr_reg intr_reg;
+ );
+ libeth_cacheline_group(read_write,
+ struct napi_struct napi;
+ u16 total_events;
+
+ struct dim tx_dim;
+ u16 tx_itr_value;
+ bool tx_intr_mode;
+ u32 tx_itr_idx;
+
+ struct dim rx_dim;
+ u16 rx_itr_value;
+ bool rx_intr_mode;
+ u32 rx_itr_idx;
+ );
+ libeth_cacheline_group(cold,
+ u16 v_idx;
+
+ cpumask_var_t affinity_mask;
+ );
};
+libeth_cacheline_set_assert(struct idpf_q_vector, 104,
+ 424 + 2 * sizeof(struct dim),
+ 8 + sizeof(cpumask_var_t));
struct idpf_rx_queue_stats {
u64_stats_t packets;
@@ -610,6 +622,7 @@ struct idpf_txq_stash {
/**
* struct idpf_rx_queue - software structure representing a receive queue
+ * @read_mostly: CL group with rarely written hot fields
* @rx: universal receive descriptor array
* @single_buf: buffer descriptor array in singleq
* @desc_ring: virtual descriptor ring address
@@ -623,14 +636,16 @@ struct idpf_txq_stash {
* @idx: For RX queue, it is used to index to total RX queue across groups and
* used for skb reporting.
* @desc_count: Number of descriptors
+ * @rxdids: Supported RX descriptor ids
+ * @rx_ptype_lkup: LUT of Rx ptypes
+ * @read_write: CL group with both read/write hot fields
* @next_to_use: Next descriptor to use
* @next_to_clean: Next descriptor to clean
* @next_to_alloc: RX buffer to allocate at
- * @rxdids: Supported RX descriptor ids
- * @rx_ptype_lkup: LUT of Rx ptypes
* @skb: Pointer to the skb
* @stats_sync: See struct u64_stats_sync
* @q_stats: See union idpf_rx_queue_stats
+ * @cold: CL group with fields no touched on hotpath
* @q_id: Queue id
* @size: Length of descriptor ring in bytes
* @dma: Physical address of ring
@@ -641,55 +656,63 @@ struct idpf_txq_stash {
* @rx_max_pkt_size: RX max packet size
*/
struct idpf_rx_queue {
- union {
- union virtchnl2_rx_desc *rx;
- struct virtchnl2_singleq_rx_buf_desc *single_buf;
+ libeth_cacheline_group(read_mostly,
+ union {
+ union virtchnl2_rx_desc *rx;
+ struct virtchnl2_singleq_rx_buf_desc *single_buf;
- void *desc_ring;
- };
- union {
- struct {
- struct idpf_bufq_set *bufq_sets;
- struct napi_struct *napi;
+ void *desc_ring;
};
- struct {
- struct idpf_rx_buf *rx_buf;
- struct page_pool *pp;
+ union {
+ struct {
+ struct idpf_bufq_set *bufq_sets;
+ struct napi_struct *napi;
+ };
+ struct {
+ struct idpf_rx_buf *rx_buf;
+ struct page_pool *pp;
+ };
};
- };
- struct net_device *netdev;
- void __iomem *tail;
-
- DECLARE_BITMAP(flags, __IDPF_Q_FLAGS_NBITS);
- u16 idx;
- u16 desc_count;
- u16 next_to_use;
- u16 next_to_clean;
- u16 next_to_alloc;
-
- u32 rxdids;
-
- const struct idpf_rx_ptype_decoded *rx_ptype_lkup;
- struct sk_buff *skb;
-
- struct u64_stats_sync stats_sync;
- struct idpf_rx_queue_stats q_stats;
-
- /* Slowpath */
- u32 q_id;
- u32 size;
- dma_addr_t dma;
-
- struct idpf_q_vector *q_vector;
-
- u16 rx_buffer_low_watermark;
- u16 rx_hbuf_size;
- u16 rx_buf_size;
- u16 rx_max_pkt_size;
-} ____cacheline_aligned;
+ struct net_device *netdev;
+ void __iomem *tail;
+
+ DECLARE_BITMAP(flags, __IDPF_Q_FLAGS_NBITS);
+ u16 idx;
+ u16 desc_count;
+
+ u32 rxdids;
+ const struct idpf_rx_ptype_decoded *rx_ptype_lkup;
+ );
+ libeth_cacheline_group(read_write,
+ u16 next_to_use;
+ u16 next_to_clean;
+ u16 next_to_alloc;
+
+ struct sk_buff *skb;
+
+ struct u64_stats_sync stats_sync;
+ struct idpf_rx_queue_stats q_stats;
+ );
+ libeth_cacheline_group(cold,
+ u32 q_id;
+ u32 size;
+ dma_addr_t dma;
+
+ struct idpf_q_vector *q_vector;
+
+ u16 rx_buffer_low_watermark;
+ u16 rx_hbuf_size;
+ u16 rx_buf_size;
+ u16 rx_max_pkt_size;
+ );
+};
+libeth_cacheline_set_assert(struct idpf_rx_queue, 64,
+ 72 + sizeof(struct u64_stats_sync),
+ 32);
/**
* struct idpf_tx_queue - software structure representing a transmit queue
+ * @read_mostly: CL group with rarely written hot fields
* @base_tx: base Tx descriptor array
* @base_ctx: base Tx context descriptor array
* @flex_tx: flex Tx descriptor array
@@ -703,22 +726,7 @@ struct idpf_rx_queue {
* @idx: For TX queue, it is used as index to map between TX queue group and
* hot path TX pointers stored in vport. Used in both singleq/splitq.
* @desc_count: Number of descriptors
- * @next_to_use: Next descriptor to use
- * @next_to_clean: Next descriptor to clean
- * @netdev: &net_device corresponding to this queue
- * @cleaned_bytes: Splitq only, TXQ only: When a TX completion is received on
- * the TX completion queue, it can be for any TXQ associated
- * with that completion queue. This means we can clean up to
- * N TXQs during a single call to clean the completion queue.
- * cleaned_bytes|pkts tracks the clean stats per TXQ during
- * that single call to clean the completion queue. By doing so,
- * we can update BQL with aggregate cleaned stats for each TXQ
- * only once at the end of the cleaning routine.
- * @clean_budget: singleq only, queue cleaning budget
- * @cleaned_pkts: Number of packets cleaned for the above said case
- * @tx_max_bufs: Max buffers that can be transmitted with scatter-gather
* @tx_min_pkt_len: Min supported packet length
- * @compl_tag_bufid_m: Completion tag buffer id mask
* @compl_tag_gen_s: Completion tag generation bit
* The format of the completion tag will change based on the TXQ
* descriptor ring size so that we can maintain roughly the same level
@@ -739,68 +747,92 @@ struct idpf_rx_queue {
* --------------------------------
*
* This gives us 8*8160 = 65280 possible unique values.
+ * @netdev: &net_device corresponding to this queue
+ * @read_write: CL group with both read/write hot fields
+ * @next_to_use: Next descriptor to use
+ * @next_to_clean: Next descriptor to clean
+ * @cleaned_bytes: Splitq only, TXQ only: When a TX completion is received on
+ * the TX completion queue, it can be for any TXQ associated
+ * with that completion queue. This means we can clean up to
+ * N TXQs during a single call to clean the completion queue.
+ * cleaned_bytes|pkts tracks the clean stats per TXQ during
+ * that single call to clean the completion queue. By doing so,
+ * we can update BQL with aggregate cleaned stats for each TXQ
+ * only once at the end of the cleaning routine.
+ * @clean_budget: singleq only, queue cleaning budget
+ * @cleaned_pkts: Number of packets cleaned for the above said case
+ * @tx_max_bufs: Max buffers that can be transmitted with scatter-gather
+ * @stash: Tx buffer stash for Flow-based scheduling mode
+ * @compl_tag_bufid_m: Completion tag buffer id mask
* @compl_tag_cur_gen: Used to keep track of current completion tag generation
* @compl_tag_gen_max: To determine when compl_tag_cur_gen should be reset
- * @stash: Tx buffer stash for Flow-based scheduling mode
* @stats_sync: See struct u64_stats_sync
* @q_stats: See union idpf_tx_queue_stats
+ * @cold: CL group with fields no touched on hotpath
* @q_id: Queue id
* @size: Length of descriptor ring in bytes
* @dma: Physical address of ring
* @q_vector: Backreference to associated vector
*/
struct idpf_tx_queue {
- union {
- struct idpf_base_tx_desc *base_tx;
- struct idpf_base_tx_ctx_desc *base_ctx;
- union idpf_tx_flex_desc *flex_tx;
- struct idpf_flex_tx_ctx_desc *flex_ctx;
-
- void *desc_ring;
- };
- struct idpf_tx_buf *tx_buf;
- struct idpf_txq_group *txq_grp;
- struct device *dev;
- void __iomem *tail;
-
- DECLARE_BITMAP(flags, __IDPF_Q_FLAGS_NBITS);
- u16 idx;
- u16 desc_count;
- u16 next_to_use;
- u16 next_to_clean;
-
- struct net_device *netdev;
-
- union {
- u32 cleaned_bytes;
- u32 clean_budget;
- };
- u16 cleaned_pkts;
-
- u16 tx_max_bufs;
- u16 tx_min_pkt_len;
-
- u16 compl_tag_bufid_m;
- u16 compl_tag_gen_s;
-
- u16 compl_tag_cur_gen;
- u16 compl_tag_gen_max;
+ libeth_cacheline_group(read_mostly,
+ union {
+ struct idpf_base_tx_desc *base_tx;
+ struct idpf_base_tx_ctx_desc *base_ctx;
+ union idpf_tx_flex_desc *flex_tx;
+ struct idpf_flex_tx_ctx_desc *flex_ctx;
+
+ void *desc_ring;
+ };
+ struct idpf_tx_buf *tx_buf;
+ struct idpf_txq_group *txq_grp;
+ struct device *dev;
+ void __iomem *tail;
+
+ DECLARE_BITMAP(flags, __IDPF_Q_FLAGS_NBITS);
+ u16 idx;
+ u16 desc_count;
+
+ u16 tx_min_pkt_len;
+ u16 compl_tag_gen_s;
+
+ struct net_device *netdev;
+ );
+ libeth_cacheline_group(read_write,
+ u16 next_to_use;
+ u16 next_to_clean;
+
+ union {
+ u32 cleaned_bytes;
+ u32 clean_budget;
+ };
+ u16 cleaned_pkts;
- struct idpf_txq_stash *stash;
+ u16 tx_max_bufs;
+ struct idpf_txq_stash *stash;
- struct u64_stats_sync stats_sync;
- struct idpf_tx_queue_stats q_stats;
+ u16 compl_tag_bufid_m;
+ u16 compl_tag_cur_gen;
+ u16 compl_tag_gen_max;
- /* Slowpath */
- u32 q_id;
- u32 size;
- dma_addr_t dma;
+ struct u64_stats_sync stats_sync;
+ struct idpf_tx_queue_stats q_stats;
+ );
+ libeth_cacheline_group(cold,
+ u32 q_id;
+ u32 size;
+ dma_addr_t dma;
- struct idpf_q_vector *q_vector;
-} ____cacheline_aligned;
+ struct idpf_q_vector *q_vector;
+ );
+};
+libeth_cacheline_set_assert(struct idpf_tx_queue, 64,
+ 88 + sizeof(struct u64_stats_sync),
+ 24);
/**
* struct idpf_buf_queue - software structure representing a buffer queue
+ * @read_mostly: CL group with rarely written hot fields
* @split_buf: buffer descriptor array
* @rx_buf: Struct with RX buffer related members
* @rx_buf.buf: See struct idpf_rx_buf
@@ -810,9 +842,11 @@ struct idpf_tx_queue {
* @tail: Tail offset
* @flags: See enum idpf_queue_flags_t
* @desc_count: Number of descriptors
+ * @read_write: CL group with both read/write hot fields
* @next_to_use: Next descriptor to use
* @next_to_clean: Next descriptor to clean
* @next_to_alloc: RX buffer to allocate at
+ * @cold: CL group with fields no touched on hotpath
* @q_id: Queue id
* @size: Length of descriptor ring in bytes
* @dma: Physical address of ring
@@ -822,79 +856,95 @@ struct idpf_tx_queue {
* @rx_buf_size: Buffer size
*/
struct idpf_buf_queue {
- struct virtchnl2_splitq_rx_buf_desc *split_buf;
- struct {
- struct idpf_rx_buf *buf;
- dma_addr_t hdr_buf_pa;
- void *hdr_buf_va;
- } rx_buf;
- struct page_pool *pp;
- void __iomem *tail;
-
- DECLARE_BITMAP(flags, __IDPF_Q_FLAGS_NBITS);
- u16 desc_count;
- u16 next_to_use;
- u16 next_to_clean;
- u16 next_to_alloc;
-
- /* Slowpath */
- u32 q_id;
- u32 size;
- dma_addr_t dma;
-
- struct idpf_q_vector *q_vector;
-
- u16 rx_buffer_low_watermark;
- u16 rx_hbuf_size;
- u16 rx_buf_size;
-} ____cacheline_aligned;
+ libeth_cacheline_group(read_mostly,
+ struct virtchnl2_splitq_rx_buf_desc *split_buf;
+ struct {
+ struct idpf_rx_buf *buf;
+ dma_addr_t hdr_buf_pa;
+ void *hdr_buf_va;
+ } rx_buf;
+ struct page_pool *pp;
+ void __iomem *tail;
+
+ DECLARE_BITMAP(flags, __IDPF_Q_FLAGS_NBITS);
+ u32 desc_count;
+ );
+ libeth_cacheline_group(read_write,
+ u32 next_to_use;
+ u32 next_to_clean;
+ u32 next_to_alloc;
+ );
+ libeth_cacheline_group(cold,
+ u32 q_id;
+ u32 size;
+ dma_addr_t dma;
+
+ struct idpf_q_vector *q_vector;
+
+ u16 rx_buffer_low_watermark;
+ u16 rx_hbuf_size;
+ u16 rx_buf_size;
+ );
+};
+libeth_cacheline_set_assert(struct idpf_buf_queue, 64, 16, 32);
/**
* struct idpf_compl_queue - software structure representing a completion queue
+ * @read_mostly: CL group with rarely written hot fields
* @comp: completion descriptor array
* @txq_grp: See struct idpf_txq_group
* @flags: See enum idpf_queue_flags_t
* @desc_count: Number of descriptors
+ * @clean_budget: queue cleaning budget
+ * @netdev: &net_device corresponding to this queue
+ * @read_write: CL group with both read/write hot fields
* @next_to_use: Next descriptor to use. Relevant in both split & single txq
* and bufq.
* @next_to_clean: Next descriptor to clean
- * @netdev: &net_device corresponding to this queue
- * @clean_budget: queue cleaning budget
* @num_completions: Only relevant for TX completion queue. It tracks the
* number of completions received to compare against the
* number of completions pending, as accumulated by the
* TX queues.
+ * @cold: CL group with fields no touched on hotpath
* @q_id: Queue id
* @size: Length of descriptor ring in bytes
* @dma: Physical address of ring
* @q_vector: Backreference to associated vector
*/
struct idpf_compl_queue {
- struct idpf_splitq_tx_compl_desc *comp;
- struct idpf_txq_group *txq_grp;
-
- DECLARE_BITMAP(flags, __IDPF_Q_FLAGS_NBITS);
- u16 desc_count;
- u16 next_to_use;
- u16 next_to_clean;
-
- struct net_device *netdev;
- u32 clean_budget;
- u32 num_completions;
+ libeth_cacheline_group(read_mostly,
+ struct idpf_splitq_tx_compl_desc *comp;
+ struct idpf_txq_group *txq_grp;
- /* Slowpath */
- u32 q_id;
- u32 size;
- dma_addr_t dma;
+ DECLARE_BITMAP(flags, __IDPF_Q_FLAGS_NBITS);
+ u32 desc_count;
- struct idpf_q_vector *q_vector;
-} ____cacheline_aligned;
+ u32 clean_budget;
+ struct net_device *netdev;
+ );
+ libeth_cacheline_group(read_write,
+ u32 next_to_use;
+ u32 next_to_clean;
+
+ u32 num_completions;
+ );
+ libeth_cacheline_group(cold,
+ u32 q_id;
+ u32 size;
+ dma_addr_t dma;
+
+ struct idpf_q_vector *q_vector;
+ );
+};
+libeth_cacheline_set_assert(struct idpf_compl_queue, 40, 16, 24);
/**
* struct idpf_sw_queue
+ * @read_mostly: CL group with rarely written hot fields
* @ring: Pointer to the ring
* @flags: See enum idpf_queue_flags_t
* @desc_count: Descriptor count
+ * @read_write: CL group with both read/write hot fields
* @next_to_use: Buffer to allocate at
* @next_to_clean: Next descriptor to clean
*
@@ -903,13 +953,20 @@ struct idpf_compl_queue {
* lockless buffer management system and are strictly software only constructs.
*/
struct idpf_sw_queue {
- u32 *ring;
-
- DECLARE_BITMAP(flags, __IDPF_Q_FLAGS_NBITS);
- u16 desc_count;
- u16 next_to_use;
- u16 next_to_clean;
-} ____cacheline_aligned;
+ libeth_cacheline_group(read_mostly,
+ u32 *ring;
+
+ DECLARE_BITMAP(flags, __IDPF_Q_FLAGS_NBITS);
+ u32 desc_count;
+ );
+ libeth_cacheline_group(read_write,
+ u32 next_to_use;
+ u32 next_to_clean;
+ );
+};
+libeth_cacheline_group_assert(struct idpf_sw_queue, read_mostly, 24);
+libeth_cacheline_group_assert(struct idpf_sw_queue, read_write, 8);
+libeth_cacheline_struct_assert(struct idpf_sw_queue, 24, 8);
/**
* struct idpf_rxq_set
--
2.45.1