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Date: Fri, 23 Oct 2009 19:32:13 +0100
From: Ben Hutchings <bhutchings@...arflare.com>
To: David Miller <davem@...emloft.net>
Cc: netdev@...r.kernel.org, linux-net-drivers@...arflare.com
Subject: [PATCH 18/27] sfc: Maintain interrupt moderation values in ticks,
not microseconds
This simplifies the implementation a lot.
Signed-off-by: Ben Hutchings <bhutchings@...arflare.com>
---
drivers/net/sfc/efx.c | 41 +++++++++++++++++++++++------------------
drivers/net/sfc/ethtool.c | 8 +++-----
drivers/net/sfc/falcon.c | 11 +----------
drivers/net/sfc/net_driver.h | 2 +-
4 files changed, 28 insertions(+), 34 deletions(-)
diff --git a/drivers/net/sfc/efx.c b/drivers/net/sfc/efx.c
index 862e483..30951fb 100644
--- a/drivers/net/sfc/efx.c
+++ b/drivers/net/sfc/efx.c
@@ -228,26 +228,20 @@ static int efx_poll(struct napi_struct *napi, int budget)
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);
+ if (channel->irq_moderation > 1) {
+ channel->irq_moderation -= 1;
+ falcon_set_int_moderation(channel);
+ }
} 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 <
+ efx->irq_rx_moderation) {
+ channel->irq_moderation += 1;
+ falcon_set_int_moderation(channel);
+ }
}
-
- if (channel->irq_moderation != old_irq_moderation)
- falcon_set_int_moderation(channel);
-
channel->irq_count = 0;
channel->irq_mod_score = 0;
}
@@ -1220,22 +1214,33 @@ void efx_flush_queues(struct efx_nic *efx)
*
**************************************************************************/
+static unsigned irq_mod_ticks(int usecs, int resolution)
+{
+ if (usecs <= 0)
+ return 0; /* cannot receive interrupts ahead of time :-) */
+ if (usecs < resolution)
+ return 1; /* never round down to 0 */
+ return usecs / resolution;
+}
+
/* Set interrupt moderation parameters */
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;
+ unsigned tx_ticks = irq_mod_ticks(tx_usecs, FALCON_IRQ_MOD_RESOLUTION);
+ unsigned rx_ticks = irq_mod_ticks(rx_usecs, FALCON_IRQ_MOD_RESOLUTION);
EFX_ASSERT_RESET_SERIALISED(efx);
efx_for_each_tx_queue(tx_queue, efx)
- tx_queue->channel->irq_moderation = tx_usecs;
+ tx_queue->channel->irq_moderation = tx_ticks;
efx->irq_rx_adaptive = rx_adaptive;
- efx->irq_rx_moderation = rx_usecs;
+ efx->irq_rx_moderation = rx_ticks;
efx_for_each_rx_queue(rx_queue, efx)
- rx_queue->channel->irq_moderation = rx_usecs;
+ rx_queue->channel->irq_moderation = rx_ticks;
}
/**************************************************************************
diff --git a/drivers/net/sfc/ethtool.c b/drivers/net/sfc/ethtool.c
index 45018f2..a313b61 100644
--- a/drivers/net/sfc/ethtool.c
+++ b/drivers/net/sfc/ethtool.c
@@ -618,6 +618,9 @@ static int efx_ethtool_get_coalesce(struct net_device *net_dev,
coalesce->use_adaptive_rx_coalesce = efx->irq_rx_adaptive;
coalesce->rx_coalesce_usecs_irq = efx->irq_rx_moderation;
+ coalesce->tx_coalesce_usecs_irq *= FALCON_IRQ_MOD_RESOLUTION;
+ coalesce->rx_coalesce_usecs_irq *= FALCON_IRQ_MOD_RESOLUTION;
+
return 0;
}
@@ -656,11 +659,6 @@ static int efx_ethtool_set_coalesce(struct net_device *net_dev,
}
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
- * (e.g. to allow for hardware timer granularity).
- */
efx_for_each_channel(channel, efx)
falcon_set_int_moderation(channel);
diff --git a/drivers/net/sfc/falcon.c b/drivers/net/sfc/falcon.c
index 1582df7..e3c33fa 100644
--- a/drivers/net/sfc/falcon.c
+++ b/drivers/net/sfc/falcon.c
@@ -1063,20 +1063,11 @@ void falcon_set_int_moderation(struct efx_channel *channel)
/* Set timer register */
if (channel->irq_moderation) {
- /* Round to resolution supported by hardware. The value we
- * program is based at 0. So actual interrupt moderation
- * achieved is ((x + 1) * 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,
FRF_AB_TC_TIMER_MODE,
FFE_BB_TIMER_MODE_INT_HLDOFF,
FRF_AB_TC_TIMER_VAL,
- channel->irq_moderation /
- FALCON_IRQ_MOD_RESOLUTION - 1);
+ channel->irq_moderation - 1);
} else {
EFX_POPULATE_DWORD_2(timer_cmd,
FRF_AB_TC_TIMER_MODE,
diff --git a/drivers/net/sfc/net_driver.h b/drivers/net/sfc/net_driver.h
index 25b7933..c8b6998 100644
--- a/drivers/net/sfc/net_driver.h
+++ b/drivers/net/sfc/net_driver.h
@@ -327,7 +327,7 @@ enum efx_rx_alloc_method {
* @used_flags: Channel is used by net driver
* @enabled: Channel enabled indicator
* @irq: IRQ number (MSI and MSI-X only)
- * @irq_moderation: IRQ moderation value (in us)
+ * @irq_moderation: IRQ moderation value (in hardware ticks)
* @napi_dev: Net device used with NAPI
* @napi_str: NAPI control structure
* @reset_work: Scheduled reset work thread
--
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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