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Date: Fri, 16 Dec 2011 10:19:46 -0800
From: David Decotigny <decot@...glers.com>
To: Matt Carlson <mcarlson@...adcom.com>,
Michael Chan <mchan@...adcom.com>, netdev@...r.kernel.org,
linux-kernel@...r.kernel.org
Cc: Javier Martinez Canillas <martinez.javier@...il.com>,
Robin Getz <rgetz@...ckfin.uclinux.org>,
Matt Mackall <mpm@...enic.com>, Ying Cai <ycai@...gle.com>,
David Decotigny <decot@...glers.com>
Subject: [PATCH net-next v1 3/6] tg3: Implement adaptive interrupt coalescing
From: Ying Cai <ycai@...gle.com>
Implement adaptive coalescing in the tg3 driver. On an opteron-based
test system, interrupt rate can be reduced from 40K intrs/sec to less
than 10K intrs/sec on netperf tests, with netperf performances gaining
2 to 14% (depending on the tests).
Example with 200 netperf streams in parallel for 100s, irq/s measured
at the netperf client host, netperf figure is cumulative on all 200
streams:
Without this patch:
TCP_RR netperf=284208 eth0 irq/s=55141.9
TCP_CRR netperf=32204.5 eth0 irq/s=15727.7
TCP_MAERTS netperf=944.68 eth0 irq/s=16255.5
pktgen loopback (pkt_size 60) 484718 pps
With patch:
TCP_RR netperf=317511 (111.72%) eth0 irq/s=8307.77 (15.07%)
TCP_CRR netperf=35890.1 (111.44%) eth0 irq/s=4390.89 (27.92%)
TCP_MAERTS netperf=971.64 (102.85%) eth0 irq/s=8135.58 (50.05%)
pktgen loopback (pkt_size 60) 552185 pps (113.92%)
Signed-off-by: David Decotigny <decot@...glers.com>
---
drivers/net/ethernet/broadcom/tg3.c | 174 +++++++++++++++++++++++++++++++++++
drivers/net/ethernet/broadcom/tg3.h | 37 ++++++++
2 files changed, 211 insertions(+), 0 deletions(-)
diff --git a/drivers/net/ethernet/broadcom/tg3.c b/drivers/net/ethernet/broadcom/tg3.c
index a65b419..9deb6a6 100644
--- a/drivers/net/ethernet/broadcom/tg3.c
+++ b/drivers/net/ethernet/broadcom/tg3.c
@@ -52,6 +52,7 @@
#include <linux/io.h>
#include <asm/byteorder.h>
#include <linux/uaccess.h>
+#include <linux/jiffies.h>
#ifdef CONFIG_SPARC
#include <asm/idprom.h>
@@ -413,6 +414,9 @@ static const struct {
#define TG3_NUM_TEST ARRAY_SIZE(ethtool_test_keys)
+static inline void tg3_full_lock(struct tg3 *tp, int irq_sync);
+static inline void tg3_full_unlock(struct tg3 *tp);
+
static void tg3_write32(struct tg3 *tp, u32 off, u32 val)
{
writel(val, tp->regs + off);
@@ -5503,6 +5507,168 @@ static void tg3_recycle_rx(struct tg3_napi *tnapi,
src_map->data = NULL;
}
+static inline int tg3_coal_adaptive_init(struct tg3 *tp)
+{
+ tp->ad.rx_jiffies = jiffies;
+ tp->ad.rx_interval = 0;
+ tp->ad.rx_frames = 0;
+ tp->ad.rx_average_frames = 0;
+ tp->ad.rx_reg_frames = TG3_COAL_RX_FRAMES;
+ tp->ad.rx_adaptive_mode = TG3_COAL_ADAPTIVE_MODE;
+ tp->ad.rx_frames_high = TG3_COAL_ADAPTIVE_MAX_FRAMES;
+ tp->ad.rx_usecs_high = TG3_COAL_ADAPTIVE_MAX_USECS;
+ tp->ad.rx_sample_interval = msecs_to_jiffies(TG3_COAL_ADAPTIVE_SAMPLE);
+
+ /* over-write tg3 stored coalescing values. Using 2.6.11 tg3
+ * adaptive coalescing values
+ */
+ tp->coal.rx_coalesce_usecs = TG3_COAL_RX_TICKS;
+ tp->coal.tx_coalesce_usecs = TG3_COAL_TX_TICKS;
+ tp->coal.rx_max_coalesced_frames = TG3_COAL_RX_FRAMES;
+ tp->coal.tx_max_coalesced_frames = TG3_COAL_TX_FRAMES;
+ tp->coal.rx_max_coalesced_frames_irq = TG3_COAL_RX_FRAMES;
+
+ return 0;
+}
+
+static int tg3_coal_adaptive_set(struct net_device *dev,
+ struct ethtool_coalesce *cmd)
+{
+ struct tg3 *tp = netdev_priv(dev);
+ int i = 0;
+
+ tg3_full_lock(tp, 0);
+ /* changing adaptive coalescing resets the rx frames coalescing to
+ * the default value. turning off adaptive coalescing, means use the
+ * default behavior, while turning it on means starts computing now....
+ * note that this is done before setting any hardcoded values, thus
+ * allowing a single call to turn off adaptive coalescing and setting
+ * a new value for hard coded (static) coalescing
+ */
+
+ /* reset host coalescing engine. */
+ tw32(HOSTCC_MODE, 0);
+ for (i = 0; i < 2000; i++) {
+ if (!(tr32(HOSTCC_MODE) & HOSTCC_MODE_ENABLE))
+ break;
+ udelay(10);
+ }
+
+ if (tp->ad.rx_adaptive_mode != cmd->use_adaptive_rx_coalesce) {
+ tp->ad.rx_jiffies = jiffies;
+ tp->ad.rx_frames = 0;
+ tp->ad.rx_interval = 0;
+ tp->ad.rx_average_frames = 0;
+ }
+
+ tp->ad.rx_adaptive_mode = cmd->use_adaptive_rx_coalesce;
+ tp->ad.rx_usecs_high = cmd->rx_coalesce_usecs_high;
+ tp->ad.rx_frames_high = cmd->rx_max_coalesced_frames_high;
+ tp->ad.rx_sample_interval = msecs_to_jiffies(cmd->rate_sample_interval);
+
+ tw32(HOSTCC_MODE, HOSTCC_MODE_ENABLE | tp->coalesce_mode);
+
+ tg3_full_unlock(tp);
+
+ return 0;
+}
+
+static int tg3_coal_adaptive_get(struct net_device *dev,
+ struct ethtool_coalesce *cmd)
+{
+ struct tg3 *tp = netdev_priv(dev);
+
+ if (tp->ad.rx_adaptive_mode) {
+ tg3_full_lock(tp, 0);
+
+ cmd->rx_coalesce_usecs = tr32(HOSTCC_RXCOL_TICKS);
+ cmd->rx_max_coalesced_frames = tr32(HOSTCC_RXMAX_FRAMES);
+
+ cmd->tx_coalesce_usecs = tr32(HOSTCC_TXCOL_TICKS);
+ cmd->tx_max_coalesced_frames = tr32(HOSTCC_TXMAX_FRAMES);
+
+ cmd->rx_max_coalesced_frames_irq = tr32(HOSTCC_RXCOAL_MAXF_INT);
+ cmd->tx_max_coalesced_frames_irq = tr32(HOSTCC_TXCOAL_MAXF_INT);
+
+ cmd->use_adaptive_rx_coalesce = tp->ad.rx_adaptive_mode;
+ cmd->rx_coalesce_usecs_high = tp->ad.rx_usecs_high;
+ cmd->rx_max_coalesced_frames_high = tp->ad.rx_frames_high;
+ cmd->rate_sample_interval = jiffies_to_msecs(
+ tp->ad.rx_sample_interval);
+
+ tg3_full_unlock(tp);
+ }
+ return 0;
+}
+
+static inline int tg3_coal_adaptive_rx(struct tg3 *tp, int received)
+{
+ unsigned long cur_jiffies = jiffies;
+
+ unsigned long diff = cur_jiffies - tp->ad.rx_jiffies;
+
+ tp->ad.rx_interval += diff;
+
+ tp->ad.rx_jiffies = cur_jiffies;
+ tp->ad.rx_frames += received;
+
+ if ((tp->ad.rx_interval >= tp->ad.rx_sample_interval) &&
+ (0 != tp->ad.rx_interval)) {
+ unsigned long rx_rate;
+
+ /* average packet per ms */
+ tp->ad.rx_frames /= jiffies_to_msecs(tp->ad.rx_interval);
+ /* apply coalescing factor */
+ tp->ad.rx_frames >>= TG3_COAL_FACTOR_EXP;
+
+ /* compute a running average of the packet rate
+ * the goal of the running average is to provide a faster
+ * response to lowering rate compare to slowly increasing rate.
+ *
+ * if the new sample interval rate as decreased from the running
+ * average, set the register coalescing to new sample interval
+ * rate. else, average the new rate with the running average
+ */
+ tp->ad.rx_average_frames += tp->ad.rx_frames;
+ tp->ad.rx_average_frames >>= 1;
+
+ if (tp->ad.rx_frames <= tp->ad.rx_average_frames)
+ rx_rate = tp->ad.rx_frames;
+ else
+ rx_rate = tp->ad.rx_average_frames;
+
+ /* adjust based on max values. Also do not set a '0' value in
+ * the average frames, always set the average to at least one
+ * frame. From the BCM documentation it is recommended to set
+ * the register value to get an interrupt for every rx packet.
+ * we could use 0, which would disable coalescing and should
+ * have the same result.
+ */
+ if (rx_rate > tp->ad.rx_frames_high)
+ rx_rate = tp->ad.rx_frames_high;
+ else if (0 == rx_rate)
+ rx_rate = 1;
+
+ if (rx_rate != tp->ad.rx_reg_frames) {
+ unsigned long rx_usecs;
+ rx_usecs = rx_rate * TG3_COAL_TICK_PER_FRAME;
+ if (rx_usecs > tp->ad.rx_usecs_high)
+ rx_usecs = tp->ad.rx_usecs_high;
+
+ tw32(HOSTCC_RXCOL_TICKS, rx_usecs);
+ tw32(HOSTCC_RXMAX_FRAMES, rx_rate);
+ tw32(HOSTCC_RXCOAL_MAXF_INT, rx_rate);
+ tp->ad.rx_reg_frames = rx_rate;
+ }
+
+ tp->ad.rx_frames = 0;
+ tp->ad.rx_interval = 0;
+
+ }
+
+ return 0;
+}
+
/* The RX ring scheme is composed of multiple rings which post fresh
* buffers to the chip, and one special ring the chip uses to report
* status back to the host.
@@ -5679,6 +5845,9 @@ next_pkt_nopost:
}
}
+ if (TG3_COAL_ADAPTIVE_ON == tp->ad.rx_adaptive_mode)
+ tg3_coal_adaptive_rx(tp, received);
+
/* ACK the status ring. */
tnapi->rx_rcb_ptr = sw_idx;
tw32_rx_mbox(tnapi->consmbox, sw_idx);
@@ -11866,6 +12035,7 @@ static int tg3_get_coalesce(struct net_device *dev, struct ethtool_coalesce *ec)
struct tg3 *tp = netdev_priv(dev);
memcpy(ec, &tp->coal, sizeof(*ec));
+ tg3_coal_adaptive_get(dev, ec);
return 0;
}
@@ -11915,6 +12085,8 @@ static int tg3_set_coalesce(struct net_device *dev, struct ethtool_coalesce *ec)
tp->coal.tx_max_coalesced_frames_irq = ec->tx_max_coalesced_frames_irq;
tp->coal.stats_block_coalesce_usecs = ec->stats_block_coalesce_usecs;
+ tg3_coal_adaptive_set(dev, ec);
+
if (netif_running(dev)) {
tg3_full_lock(tp, 0);
__tg3_set_coalesce(tp, &tp->coal);
@@ -15319,6 +15491,8 @@ static void __devinit tg3_init_coal(struct tg3 *tp)
ec->tx_coalesce_usecs_irq = 0;
ec->stats_block_coalesce_usecs = 0;
}
+
+ tg3_coal_adaptive_init(tp);
}
static const struct net_device_ops tg3_netdev_ops = {
diff --git a/drivers/net/ethernet/broadcom/tg3.h b/drivers/net/ethernet/broadcom/tg3.h
index aea8f72..695cf14 100644
--- a/drivers/net/ethernet/broadcom/tg3.h
+++ b/drivers/net/ethernet/broadcom/tg3.h
@@ -3211,6 +3211,43 @@ struct tg3 {
struct ethtool_coalesce coal;
+ struct {
+ unsigned long rx_jiffies; /* last read jiffies */
+ unsigned long rx_interval; /* rcv interval in jiffies */
+ unsigned long rx_reg_frames; /* current register value */
+ unsigned long rx_frames; /* received frame in interval*/
+ unsigned long rx_average_frames; /* computed received average */
+ unsigned int rx_adaptive_mode; /* adaptive mode on/off */
+ unsigned long rx_frames_high; /* max coalescing frame in */
+ /* adaptive mode */
+ unsigned long rx_usecs_high; /* max usecs in adaptive */
+ /* mode */
+ unsigned long rx_sample_interval;/* adaptive sample rate */
+ /* in jiffies (msecs) */
+ } ad; /* adaptive coalescing */
+
+#define TG3_COAL_ADAPTIVE_ON 1
+#define TG3_COAL_ADAPTIVE_OFF 0
+#define TG3_COAL_ADAPTIVE_MODE TG3_COAL_ADAPTIVE_ON
+
+/* Ticks are in TG3 register units and not in system units */
+#define TG3_COAL_FACTOR_EXP 3 /* coalescence factor, num irq per ms max. */
+ /* this is the exponent of a power of two. */
+
+#define TG3_COAL_TICK_PER_FRAME 10 /* tick per frame, num of us per tick */
+ /* per frame. Used tg3 ms tick unit */
+
+#define TG3_COAL_ADAPTIVE_MAX_FRAMES 32
+#define TG3_COAL_ADAPTIVE_MAX_USECS (TG3_COAL_ADAPTIVE_MAX_FRAMES \
+ << TG3_COAL_TICK_PER_FRAME)
+
+#define TG3_COAL_ADAPTIVE_SAMPLE 10 /* ms samples */
+
+#define TG3_COAL_TX_FRAMES 32 /* must be <= to 1/2 TG3_TX_RING_SIZE */
+#define TG3_COAL_TX_TICKS (TG3_COAL_TX_FRAMES * TG3_COAL_TICK_PER_FRAME)
+#define TG3_COAL_RX_FRAMES 1
+#define TG3_COAL_RX_TICKS (TG3_COAL_RX_FRAMES * TG3_COAL_TICK_PER_FRAME)
+
/* firmware info */
const char *fw_needed;
const struct firmware *fw;
--
1.7.3.1
--
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