From eff3549c5883a9abc5dbff00c084cabbcfdf4437 Mon Sep 17 00:00:00 2001 From: Thibaut VARENE Date: Tue, 12 Sep 2017 23:22:37 +0200 Subject: [PATCH] generic: drop support for get_port_stats() on ar8xxx The implementation is not efficient on ar8xxx switches. It triggers high CPU load and degrades device performance. The high CPU load has been traced down to the ar8xxx_reg_wait() call in ar8xxx_mib_op(), which has to usleep_range() till the MIB busy flag set by the request to update the MIB counter is cleared. This commit removes the get_port_stats() code introduced in 4d8a66d and leaves a note for future hacker's beware. Fixes: FS#1004 Signed-off-by: Thibaut VARENE --- .../generic/files/drivers/net/phy/ar8216.c | 65 +++---------------- .../generic/files/drivers/net/phy/ar8216.h | 3 - .../generic/files/drivers/net/phy/ar8327.c | 9 +++ 3 files changed, 18 insertions(+), 59 deletions(-) diff --git a/target/linux/generic/files/drivers/net/phy/ar8216.c b/target/linux/generic/files/drivers/net/phy/ar8216.c index 7f3d5115ab09..61811370de60 100644 --- a/target/linux/generic/files/drivers/net/phy/ar8216.c +++ b/target/linux/generic/files/drivers/net/phy/ar8216.c @@ -49,12 +49,6 @@ extern const struct ar8xxx_chip ar8337_chip; .name = (_n), \ } -#define AR8216_MIB_RXB_ID 14 /* RxGoodByte */ -#define AR8216_MIB_TXB_ID 29 /* TxByte */ - -#define AR8236_MIB_RXB_ID 15 /* RxGoodByte */ -#define AR8236_MIB_TXB_ID 31 /* TxByte */ - static const struct ar8xxx_mib_desc ar8216_mibs[] = { MIB_DESC(1, AR8216_STATS_RXBROAD, "RxBroad"), MIB_DESC(1, AR8216_STATS_RXPAUSE, "RxPause"), @@ -1587,56 +1581,6 @@ ar8xxx_sw_set_flush_port_arl_table(struct switch_dev *dev, return ret; } -int -ar8xxx_sw_get_port_stats(struct switch_dev *dev, int port, - struct switch_port_stats *stats) -{ - struct ar8xxx_priv *priv = swdev_to_ar8xxx(dev); - u64 *mib_stats; - int ret; - int mib_txb_id, mib_rxb_id; - - if (!ar8xxx_has_mib_counters(priv)) - return -EOPNOTSUPP; - - if (port >= dev->ports) - return -EINVAL; - - switch (priv->chip_ver) { - case AR8XXX_VER_AR8216: - mib_txb_id = AR8216_MIB_TXB_ID; - mib_rxb_id = AR8216_MIB_RXB_ID; - break; - case AR8XXX_VER_AR8236: - case AR8XXX_VER_AR8316: - case AR8XXX_VER_AR8327: - case AR8XXX_VER_AR8337: - mib_txb_id = AR8236_MIB_TXB_ID; - mib_rxb_id = AR8236_MIB_RXB_ID; - break; - default: - return -EOPNOTSUPP; - } - - mutex_lock(&priv->mib_lock); - ret = ar8xxx_mib_capture(priv); - if (ret) - goto unlock; - - ar8xxx_mib_fetch_port_stat(priv, port, false); - - mib_stats = &priv->mib_stats[port * priv->chip->num_mibs]; - - stats->tx_bytes = mib_stats[mib_txb_id]; - stats->rx_bytes = mib_stats[mib_rxb_id]; - - ret = 0; - -unlock: - mutex_unlock(&priv->mib_lock); - return ret; -} - static const struct switch_attr ar8xxx_sw_attr_globals[] = { { .type = SWITCH_TYPE_INT, @@ -1752,7 +1696,16 @@ static const struct switch_dev_ops ar8xxx_sw_ops = { .apply_config = ar8xxx_sw_hw_apply, .reset_switch = ar8xxx_sw_reset_switch, .get_port_link = ar8xxx_sw_get_port_link, +/* The following op is disabled as it hogs the CPU and degrades performance. + An implementation has been attempted in 4d8a66d but reading MIB data is slow + on ar8xxx switches. + + The high CPU load has been traced down to the ar8xxx_reg_wait() call in + ar8xxx_mib_op(), which has to usleep_range() till the MIB busy flag set by + the request to update the MIB counter is cleared. */ +#if 0 .get_port_stats = ar8xxx_sw_get_port_stats, +#endif }; static const struct ar8xxx_chip ar8216_chip = { diff --git a/target/linux/generic/files/drivers/net/phy/ar8216.h b/target/linux/generic/files/drivers/net/phy/ar8216.h index 321eeb79231f..d9508b9ff83c 100644 --- a/target/linux/generic/files/drivers/net/phy/ar8216.h +++ b/target/linux/generic/files/drivers/net/phy/ar8216.h @@ -566,9 +566,6 @@ ar8xxx_sw_set_flush_port_arl_table(struct switch_dev *dev, const struct switch_attr *attr, struct switch_val *val); int -ar8xxx_sw_get_port_stats(struct switch_dev *dev, int port, - struct switch_port_stats *stats); -int ar8216_wait_bit(struct ar8xxx_priv *priv, int reg, u32 mask, u32 val); static inline struct ar8xxx_priv * diff --git a/target/linux/generic/files/drivers/net/phy/ar8327.c b/target/linux/generic/files/drivers/net/phy/ar8327.c index bae9744736c6..6ebd2e8aedf3 100644 --- a/target/linux/generic/files/drivers/net/phy/ar8327.c +++ b/target/linux/generic/files/drivers/net/phy/ar8327.c @@ -1411,7 +1411,16 @@ static const struct switch_dev_ops ar8327_sw_ops = { .apply_config = ar8327_sw_hw_apply, .reset_switch = ar8xxx_sw_reset_switch, .get_port_link = ar8xxx_sw_get_port_link, +/* The following op is disabled as it hogs the CPU and degrades performance. + An implementation has been attempted in 4d8a66d but reading MIB data is slow + on ar8xxx switches. + + The high CPU load has been traced down to the ar8xxx_reg_wait() call in + ar8xxx_mib_op(), which has to usleep_range() till the MIB busy flag set by + the request to update the MIB counter is cleared. */ +#if 0 .get_port_stats = ar8xxx_sw_get_port_stats, +#endif }; const struct ar8xxx_chip ar8327_chip = { -- 2.30.2