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Message-ID: <1292002687.11673.15.camel@bwh-desktop>
Date: Fri, 10 Dec 2010 17:38:07 +0000
From: Ben Hutchings <bhutchings@...arflare.com>
To: David Miller <davem@...emloft.net>
Cc: netdev@...r.kernel.org, linux-net-drivers@...arflare.com
Subject: [PATCH net-next-2.6 01/10] sfc: Reorder struct efx_nic to separate
fields by volatility
Place the regularly updated fields (locks, MAC stats, etc.) on a
separate cache-line from fields which are mostly constant. This
should reduce cache misses for access to the latter on the data path.
Signed-off-by: Ben Hutchings <bhutchings@...arflare.com>
---
drivers/net/sfc/net_driver.h | 41 +++++++++++++++++++++++------------------
1 files changed, 23 insertions(+), 18 deletions(-)
diff --git a/drivers/net/sfc/net_driver.h b/drivers/net/sfc/net_driver.h
index 0d19fbf..60d6371 100644
--- a/drivers/net/sfc/net_driver.h
+++ b/drivers/net/sfc/net_driver.h
@@ -625,10 +625,8 @@ struct efx_filter_state;
* Work items do not hold and must not acquire RTNL.
* @workqueue_name: Name of workqueue
* @reset_work: Scheduled reset workitem
- * @monitor_work: Hardware monitor workitem
* @membase_phys: Memory BAR value as physical address
* @membase: Memory BAR value
- * @biu_lock: BIU (bus interface unit) lock
* @interrupt_mode: Interrupt mode
* @irq_rx_adaptive: Adaptive IRQ moderation enabled for RX event queues
* @irq_rx_moderation: IRQ moderation time for RX event queues
@@ -652,14 +650,9 @@ struct efx_filter_state;
* @int_error_count: Number of internal errors seen recently
* @int_error_expire: Time at which error count will be expired
* @irq_status: Interrupt status buffer
- * @last_irq_cpu: Last CPU to handle interrupt.
- * This register is written with the SMP processor ID whenever an
- * interrupt is handled. It is used by efx_nic_test_interrupt()
- * to verify that an interrupt has occurred.
* @irq_zero_count: Number of legacy IRQs seen with queue flags == 0
* @fatal_irq_level: IRQ level (bit number) used for serious errors
* @mtd_list: List of MTDs attached to the NIC
- * @n_rx_nodesc_drop_cnt: RX no descriptor drop count
* @nic_data: Hardware dependant state
* @mac_lock: MAC access lock. Protects @port_enabled, @phy_mode,
* @port_inhibited, efx_monitor() and efx_reconfigure_port()
@@ -672,11 +665,7 @@ struct efx_filter_state;
* @port_initialized: Port initialized?
* @net_dev: Operating system network device. Consider holding the rtnl lock
* @rx_checksum_enabled: RX checksumming enabled
- * @mac_stats: MAC statistics. These include all statistics the MACs
- * can provide. Generic code converts these into a standard
- * &struct net_device_stats.
* @stats_buffer: DMA buffer for statistics
- * @stats_lock: Statistics update lock. Serialises statistics fetches
* @mac_op: MAC interface
* @phy_type: PHY type
* @phy_op: PHY interface
@@ -694,10 +683,23 @@ struct efx_filter_state;
* @loopback_mode: Loopback status
* @loopback_modes: Supported loopback mode bitmask
* @loopback_selftest: Offline self-test private state
+ * @monitor_work: Hardware monitor workitem
+ * @biu_lock: BIU (bus interface unit) lock
+ * @last_irq_cpu: Last CPU to handle interrupt.
+ * This register is written with the SMP processor ID whenever an
+ * interrupt is handled. It is used by efx_nic_test_interrupt()
+ * to verify that an interrupt has occurred.
+ * @n_rx_nodesc_drop_cnt: RX no descriptor drop count
+ * @mac_stats: MAC statistics. These include all statistics the MACs
+ * can provide. Generic code converts these into a standard
+ * &struct net_device_stats.
+ * @stats_lock: Statistics update lock. Serialises statistics fetches
*
* This is stored in the private area of the &struct net_device.
*/
struct efx_nic {
+ /* The following fields should be written very rarely */
+
char name[IFNAMSIZ];
struct pci_dev *pci_dev;
const struct efx_nic_type *type;
@@ -705,10 +707,9 @@ struct efx_nic {
struct workqueue_struct *workqueue;
char workqueue_name[16];
struct work_struct reset_work;
- struct delayed_work monitor_work;
resource_size_t membase_phys;
void __iomem *membase;
- spinlock_t biu_lock;
+
enum efx_int_mode interrupt_mode;
bool irq_rx_adaptive;
unsigned int irq_rx_moderation;
@@ -735,7 +736,6 @@ struct efx_nic {
unsigned long int_error_expire;
struct efx_buffer irq_status;
- volatile signed int last_irq_cpu;
unsigned irq_zero_count;
unsigned fatal_irq_level;
@@ -743,8 +743,6 @@ struct efx_nic {
struct list_head mtd_list;
#endif
- unsigned n_rx_nodesc_drop_cnt;
-
void *nic_data;
struct mutex mac_lock;
@@ -756,9 +754,7 @@ struct efx_nic {
struct net_device *net_dev;
bool rx_checksum_enabled;
- struct efx_mac_stats mac_stats;
struct efx_buffer stats_buffer;
- spinlock_t stats_lock;
struct efx_mac_operations *mac_op;
@@ -784,6 +780,15 @@ struct efx_nic {
void *loopback_selftest;
struct efx_filter_state *filter_state;
+
+ /* The following fields may be written more often */
+
+ struct delayed_work monitor_work ____cacheline_aligned_in_smp;
+ spinlock_t biu_lock;
+ volatile signed int last_irq_cpu;
+ unsigned n_rx_nodesc_drop_cnt;
+ struct efx_mac_stats mac_stats;
+ spinlock_t stats_lock;
};
static inline int efx_dev_registered(struct efx_nic *efx)
--
1.7.3.2
--
Ben Hutchings, Senior Software Engineer, Solarflare Communications
Not speaking for my employer; that's the marketing department's job.
They asked us to note that Solarflare product names are trademarked.
--
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