From: Ben Hutchings <bhutchings@solarflare.com>
To: David Miller <davem@davemloft.net>
Cc: netdev@vger.kernel.org, linux-net-drivers@solarflare.com
Subject: [PATCH 5/5] sfc: Implement adaptive IRQ moderation
Date: Fri, 20 Mar 2009 23:30:37 +0000 [thread overview]
Message-ID: <1237591837.3217.17.camel@achroite> (raw)
In-Reply-To: <1237591540.3217.6.camel@achroite>
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@solarflare.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.
next prev parent reply other threads:[~2009-03-20 23:30 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-03-20 23:25 [PATCH 1/5] sfc: Pad packets to 33 bytes to prevent TX packet parser lockup Ben Hutchings
2009-03-20 23:26 ` [PATCH 2/5] sfc: Work around unreliable legacy interrupt status Ben Hutchings
2009-03-22 2:09 ` David Miller
2009-03-20 23:26 ` [PATCH 3/5] sfc: Remove unused private PCI register definitions Ben Hutchings
2009-03-22 2:09 ` David Miller
2009-03-20 23:27 ` [PATCH 4/5] sfc: Optimise falcon_writel_page_locked() for page > 0 Ben Hutchings
2009-03-22 2:10 ` David Miller
2009-03-20 23:30 ` Ben Hutchings [this message]
2009-03-22 2:10 ` [PATCH 5/5] sfc: Implement adaptive IRQ moderation David Miller
2009-03-22 2:09 ` [PATCH 1/5] sfc: Pad packets to 33 bytes to prevent TX packet parser lockup David Miller
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=1237591837.3217.17.camel@achroite \
--to=bhutchings@solarflare.com \
--cc=davem@davemloft.net \
--cc=linux-net-drivers@solarflare.com \
--cc=netdev@vger.kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.