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Message-Id: <1237591837.3217.17.camel@achroite>
Date: Fri, 20 Mar 2009 23:30:37 +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 5/5] sfc: Implement adaptive IRQ moderation
Calculate a score for each 1000 IRQs:
- TX completions are worth 1 point
- RX completions are worth 4 if merged using LRO or 2 otherwise
Reduce moderation if the score is less than 10000, down to a minimum
of 5 us. Increase moderation if the score is more than 20000, up to
the specified maximum.
Signed-off-by: Ben Hutchings <bhutchings@...arflare.com>
---
drivers/net/sfc/efx.c | 46 ++++++++++++++++++++++++++++++++++++++++-
drivers/net/sfc/efx.h | 2 +-
drivers/net/sfc/ethtool.c | 19 +++++-----------
drivers/net/sfc/falcon.c | 16 ++++++++++----
drivers/net/sfc/falcon.h | 2 +
drivers/net/sfc/net_driver.h | 9 ++++++++
6 files changed, 73 insertions(+), 21 deletions(-)
diff --git a/drivers/net/sfc/efx.c b/drivers/net/sfc/efx.c
index 8fa68d8..6eff9ca 100644
--- a/drivers/net/sfc/efx.c
+++ b/drivers/net/sfc/efx.c
@@ -133,6 +133,16 @@ static int phy_flash_cfg;
module_param(phy_flash_cfg, int, 0644);
MODULE_PARM_DESC(phy_flash_cfg, "Set PHYs into reflash mode initially");
+static unsigned irq_adapt_low_thresh = 10000;
+module_param(irq_adapt_low_thresh, uint, 0644);
+MODULE_PARM_DESC(irq_adapt_low_thresh,
+ "Threshold score for reducing IRQ moderation");
+
+static unsigned irq_adapt_high_thresh = 20000;
+module_param(irq_adapt_high_thresh, uint, 0644);
+MODULE_PARM_DESC(irq_adapt_high_thresh,
+ "Threshold score for increasing IRQ moderation");
+
/**************************************************************************
*
* Utility functions and prototypes
@@ -223,6 +233,35 @@ static int efx_poll(struct napi_struct *napi, int budget)
rx_packets = efx_process_channel(channel, budget);
if (rx_packets < budget) {
+ struct efx_nic *efx = channel->efx;
+
+ if (channel->used_flags & EFX_USED_BY_RX &&
+ efx->irq_rx_adaptive &&
+ unlikely(++channel->irq_count == 1000)) {
+ unsigned old_irq_moderation = channel->irq_moderation;
+
+ if (unlikely(channel->irq_mod_score <
+ irq_adapt_low_thresh)) {
+ channel->irq_moderation =
+ max_t(int,
+ channel->irq_moderation -
+ FALCON_IRQ_MOD_RESOLUTION,
+ FALCON_IRQ_MOD_RESOLUTION);
+ } else if (unlikely(channel->irq_mod_score >
+ irq_adapt_high_thresh)) {
+ channel->irq_moderation =
+ min(channel->irq_moderation +
+ FALCON_IRQ_MOD_RESOLUTION,
+ efx->irq_rx_moderation);
+ }
+
+ if (channel->irq_moderation != old_irq_moderation)
+ falcon_set_int_moderation(channel);
+
+ channel->irq_count = 0;
+ channel->irq_mod_score = 0;
+ }
+
/* There is no race here; although napi_disable() will
* only wait for napi_complete(), this isn't a problem
* since efx_channel_processed() will have no effect if
@@ -991,7 +1030,7 @@ static int efx_probe_nic(struct efx_nic *efx)
efx_set_channels(efx);
/* Initialise the interrupt moderation settings */
- efx_init_irq_moderation(efx, tx_irq_mod_usec, rx_irq_mod_usec);
+ efx_init_irq_moderation(efx, tx_irq_mod_usec, rx_irq_mod_usec, true);
return 0;
}
@@ -1188,7 +1227,8 @@ void efx_flush_queues(struct efx_nic *efx)
**************************************************************************/
/* Set interrupt moderation parameters */
-void efx_init_irq_moderation(struct efx_nic *efx, int tx_usecs, int rx_usecs)
+void efx_init_irq_moderation(struct efx_nic *efx, int tx_usecs, int rx_usecs,
+ bool rx_adaptive)
{
struct efx_tx_queue *tx_queue;
struct efx_rx_queue *rx_queue;
@@ -1198,6 +1238,8 @@ void efx_init_irq_moderation(struct efx_nic *efx, int tx_usecs, int rx_usecs)
efx_for_each_tx_queue(tx_queue, efx)
tx_queue->channel->irq_moderation = tx_usecs;
+ efx->irq_rx_adaptive = rx_adaptive;
+ efx->irq_rx_moderation = rx_usecs;
efx_for_each_rx_queue(rx_queue, efx)
rx_queue->channel->irq_moderation = rx_usecs;
}
diff --git a/drivers/net/sfc/efx.h b/drivers/net/sfc/efx.h
index 8bde1d2..da157aa 100644
--- a/drivers/net/sfc/efx.h
+++ b/drivers/net/sfc/efx.h
@@ -52,7 +52,7 @@ extern void efx_schedule_reset(struct efx_nic *efx, enum reset_type type);
extern void efx_suspend(struct efx_nic *efx);
extern void efx_resume(struct efx_nic *efx);
extern void efx_init_irq_moderation(struct efx_nic *efx, int tx_usecs,
- int rx_usecs);
+ int rx_usecs, bool rx_adaptive);
extern int efx_request_power(struct efx_nic *efx, int mw, const char *name);
extern void efx_hex_dump(const u8 *, unsigned int, const char *);
diff --git a/drivers/net/sfc/ethtool.c b/drivers/net/sfc/ethtool.c
index 589d132..64309f4 100644
--- a/drivers/net/sfc/ethtool.c
+++ b/drivers/net/sfc/ethtool.c
@@ -604,7 +604,6 @@ static int efx_ethtool_get_coalesce(struct net_device *net_dev,
{
struct efx_nic *efx = netdev_priv(net_dev);
struct efx_tx_queue *tx_queue;
- struct efx_rx_queue *rx_queue;
struct efx_channel *channel;
memset(coalesce, 0, sizeof(*coalesce));
@@ -622,14 +621,8 @@ static int efx_ethtool_get_coalesce(struct net_device *net_dev,
}
}
- /* Find lowest IRQ moderation across all used RX queues */
- coalesce->rx_coalesce_usecs_irq = ~((u32) 0);
- efx_for_each_rx_queue(rx_queue, efx) {
- channel = rx_queue->channel;
- if (channel->irq_moderation < coalesce->rx_coalesce_usecs_irq)
- coalesce->rx_coalesce_usecs_irq =
- channel->irq_moderation;
- }
+ coalesce->use_adaptive_rx_coalesce = efx->irq_rx_adaptive;
+ coalesce->rx_coalesce_usecs_irq = efx->irq_rx_moderation;
return 0;
}
@@ -643,10 +636,9 @@ static int efx_ethtool_set_coalesce(struct net_device *net_dev,
struct efx_nic *efx = netdev_priv(net_dev);
struct efx_channel *channel;
struct efx_tx_queue *tx_queue;
- unsigned tx_usecs, rx_usecs;
+ unsigned tx_usecs, rx_usecs, adaptive;
- if (coalesce->use_adaptive_rx_coalesce ||
- coalesce->use_adaptive_tx_coalesce)
+ if (coalesce->use_adaptive_tx_coalesce)
return -EOPNOTSUPP;
if (coalesce->rx_coalesce_usecs || coalesce->tx_coalesce_usecs) {
@@ -657,6 +649,7 @@ static int efx_ethtool_set_coalesce(struct net_device *net_dev,
rx_usecs = coalesce->rx_coalesce_usecs_irq;
tx_usecs = coalesce->tx_coalesce_usecs_irq;
+ adaptive = coalesce->use_adaptive_rx_coalesce;
/* If the channel is shared only allow RX parameters to be set */
efx_for_each_tx_queue(tx_queue, efx) {
@@ -668,7 +661,7 @@ static int efx_ethtool_set_coalesce(struct net_device *net_dev,
}
}
- efx_init_irq_moderation(efx, tx_usecs, rx_usecs);
+ efx_init_irq_moderation(efx, tx_usecs, rx_usecs, adaptive);
/* Reset channel to pick up new moderation value. Note that
* this may change the value of the irq_moderation field
diff --git a/drivers/net/sfc/falcon.c b/drivers/net/sfc/falcon.c
index f42fc60..23a1b14 100644
--- a/drivers/net/sfc/falcon.c
+++ b/drivers/net/sfc/falcon.c
@@ -729,6 +729,9 @@ static void falcon_handle_tx_event(struct efx_channel *channel,
tx_ev_desc_ptr = EFX_QWORD_FIELD(*event, TX_EV_DESC_PTR);
tx_ev_q_label = EFX_QWORD_FIELD(*event, TX_EV_Q_LABEL);
tx_queue = &efx->tx_queue[tx_ev_q_label];
+ channel->irq_mod_score +=
+ (tx_ev_desc_ptr - tx_queue->read_count) &
+ efx->type->txd_ring_mask;
efx_xmit_done(tx_queue, tx_ev_desc_ptr);
} else if (EFX_QWORD_FIELD(*event, TX_EV_WQ_FF_FULL)) {
/* Rewrite the FIFO write pointer */
@@ -898,6 +901,8 @@ static void falcon_handle_rx_event(struct efx_channel *channel,
discard = true;
}
+ channel->irq_mod_score += 2;
+
/* Handle received packet */
efx_rx_packet(rx_queue, rx_ev_desc_ptr, rx_ev_byte_cnt,
checksummed, discard);
@@ -1075,14 +1080,15 @@ void falcon_set_int_moderation(struct efx_channel *channel)
* program is based at 0. So actual interrupt moderation
* achieved is ((x + 1) * res).
*/
- unsigned int res = 5;
- channel->irq_moderation -= (channel->irq_moderation % res);
- if (channel->irq_moderation < res)
- channel->irq_moderation = res;
+ channel->irq_moderation -= (channel->irq_moderation %
+ FALCON_IRQ_MOD_RESOLUTION);
+ if (channel->irq_moderation < FALCON_IRQ_MOD_RESOLUTION)
+ channel->irq_moderation = FALCON_IRQ_MOD_RESOLUTION;
EFX_POPULATE_DWORD_2(timer_cmd,
TIMER_MODE, TIMER_MODE_INT_HLDOFF,
TIMER_VAL,
- (channel->irq_moderation / res) - 1);
+ channel->irq_moderation /
+ FALCON_IRQ_MOD_RESOLUTION - 1);
} else {
EFX_POPULATE_DWORD_2(timer_cmd,
TIMER_MODE, TIMER_MODE_DIS,
diff --git a/drivers/net/sfc/falcon.h b/drivers/net/sfc/falcon.h
index 7869c3d..77f2e0d 100644
--- a/drivers/net/sfc/falcon.h
+++ b/drivers/net/sfc/falcon.h
@@ -85,6 +85,8 @@ extern void falcon_set_int_moderation(struct efx_channel *channel);
extern void falcon_disable_interrupts(struct efx_nic *efx);
extern void falcon_fini_interrupt(struct efx_nic *efx);
+#define FALCON_IRQ_MOD_RESOLUTION 5
+
/* Global Resources */
extern int falcon_probe_nic(struct efx_nic *efx);
extern int falcon_probe_resources(struct efx_nic *efx);
diff --git a/drivers/net/sfc/net_driver.h b/drivers/net/sfc/net_driver.h
index b81fc72..e169e5d 100644
--- a/drivers/net/sfc/net_driver.h
+++ b/drivers/net/sfc/net_driver.h
@@ -336,6 +336,8 @@ enum efx_rx_alloc_method {
* @eventq_read_ptr: Event queue read pointer
* @last_eventq_read_ptr: Last event queue read pointer value.
* @eventq_magic: Event queue magic value for driver-generated test events
+ * @irq_count: Number of IRQs since last adaptive moderation decision
+ * @irq_mod_score: IRQ moderation score
* @rx_alloc_level: Watermark based heuristic counter for pushing descriptors
* and diagnostic counters
* @rx_alloc_push_pages: RX allocation method currently in use for pushing
@@ -364,6 +366,9 @@ struct efx_channel {
unsigned int last_eventq_read_ptr;
unsigned int eventq_magic;
+ unsigned int irq_count;
+ unsigned int irq_mod_score;
+
int rx_alloc_level;
int rx_alloc_push_pages;
@@ -703,6 +708,8 @@ union efx_multicast_hash {
* @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
* @i2c_adap: I2C adapter
* @board_info: Board-level information
* @state: Device state flag. Serialised by the rtnl_lock.
@@ -784,6 +791,8 @@ struct efx_nic {
void __iomem *membase;
spinlock_t biu_lock;
enum efx_int_mode interrupt_mode;
+ bool irq_rx_adaptive;
+ unsigned int irq_rx_moderation;
struct i2c_adapter i2c_adap;
struct efx_board board_info;
--
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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