Messages in this thread Patch in this message | | | Date | Thu, 3 Mar 2022 03:53:27 +0200 | From | Vladimir Oltean <> | Subject | Re: [net-next PATCH v2] net: dsa: qca8k: pack driver struct and improve cache use |
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On Mon, Feb 28, 2022 at 12:04:08PM +0100, Ansuel Smith wrote: > Pack qca8k priv and other struct using pahole and set the first priv > struct entry to mgmt_master and mgmt_eth_data to speedup access. > While at it also rework pcs struct and move it qca8k_ports_config > following other configuration set for the cpu ports. > > Signed-off-by: Ansuel Smith <ansuelsmth@gmail.com> > ---
How did you "pack" struct qca8k_priv exactly?
Before:
struct qca8k_priv { u8 switch_id; /* 0 1 */ u8 switch_revision; /* 1 1 */ u8 mirror_rx; /* 2 1 */ u8 mirror_tx; /* 3 1 */ u8 lag_hash_mode; /* 4 1 */ bool legacy_phy_port_mapping; /* 5 1 */ struct qca8k_ports_config ports_config; /* 6 7 */
/* XXX 3 bytes hole, try to pack */
struct regmap * regmap; /* 16 8 */ struct mii_bus * bus; /* 24 8 */ struct ar8xxx_port_status port_sts[7]; /* 32 28 */
/* XXX 4 bytes hole, try to pack */
/* --- cacheline 1 boundary (64 bytes) --- */ struct dsa_switch * ds; /* 64 8 */ struct mutex reg_mutex; /* 72 160 */ /* --- cacheline 3 boundary (192 bytes) was 40 bytes ago --- */ struct device * dev; /* 232 8 */ struct dsa_switch_ops ops; /* 240 864 */ /* --- cacheline 17 boundary (1088 bytes) was 16 bytes ago --- */ struct gpio_desc * reset_gpio; /* 1104 8 */ unsigned int port_mtu[7]; /* 1112 28 */
/* XXX 4 bytes hole, try to pack */
struct net_device * mgmt_master; /* 1144 8 */ /* --- cacheline 18 boundary (1152 bytes) --- */ struct qca8k_mgmt_eth_data mgmt_eth_data; /* 1152 280 */ /* --- cacheline 22 boundary (1408 bytes) was 24 bytes ago --- */ struct qca8k_mib_eth_data mib_eth_data; /* 1432 272 */ /* --- cacheline 26 boundary (1664 bytes) was 40 bytes ago --- */ struct qca8k_mdio_cache mdio_cache; /* 1704 6 */
/* XXX 2 bytes hole, try to pack */
struct qca8k_pcs pcs_port_0; /* 1712 32 */
/* XXX last struct has 4 bytes of padding */
/* --- cacheline 27 boundary (1728 bytes) was 16 bytes ago --- */ struct qca8k_pcs pcs_port_6; /* 1744 32 */
/* XXX last struct has 4 bytes of padding */
/* size: 1776, cachelines: 28, members: 22 */ /* sum members: 1763, holes: 4, sum holes: 13 */ /* paddings: 2, sum paddings: 8 */ /* last cacheline: 48 bytes */ };
After:
struct qca8k_priv { struct net_device * mgmt_master; /* 0 8 */ struct qca8k_mgmt_eth_data mgmt_eth_data; /* 8 280 */ /* --- cacheline 4 boundary (256 bytes) was 32 bytes ago --- */ struct qca8k_mdio_cache mdio_cache; /* 288 6 */ u8 switch_id; /* 294 1 */ u8 switch_revision; /* 295 1 */ u8 mirror_rx; /* 296 1 */ u8 mirror_tx; /* 297 1 */ u8 lag_hash_mode; /* 298 1 */ bool legacy_phy_port_mapping; /* 299 1 */
/* XXX 4 bytes hole, try to pack */
struct qca8k_ports_config ports_config; /* 304 72 */ /* --- cacheline 5 boundary (320 bytes) was 56 bytes ago --- */ struct regmap * regmap; /* 376 8 */ /* --- cacheline 6 boundary (384 bytes) --- */ struct mii_bus * bus; /* 384 8 */ struct ar8xxx_port_status port_sts[7]; /* 392 28 */
/* XXX 4 bytes hole, try to pack */
struct dsa_switch * ds; /* 424 8 */ struct mutex reg_mutex; /* 432 160 */ /* --- cacheline 9 boundary (576 bytes) was 16 bytes ago --- */ struct device * dev; /* 592 8 */ struct gpio_desc * reset_gpio; /* 600 8 */ struct dsa_switch_ops ops; /* 608 864 */ /* --- cacheline 23 boundary (1472 bytes) --- */ struct qca8k_mib_eth_data mib_eth_data; /* 1472 280 */
/* XXX last struct has 4 bytes of padding */
/* --- cacheline 27 boundary (1728 bytes) was 24 bytes ago --- */ unsigned int port_mtu[7]; /* 1752 28 */
/* size: 1784, cachelines: 28, members: 20 */ /* sum members: 1772, holes: 2, sum holes: 8 */ /* padding: 4 */ /* paddings: 1, sum paddings: 4 */ /* last cacheline: 56 bytes */ };
1776 vs 1784. That's... larger?!
Also, struct qca8k_priv is so large because the "ops" member is a full copy of qca8k_switch_ops. I understand why commit db460c54b67f ("net: dsa: qca8k: extend slave-bus implementations") did this, but I wonder, is there no better way?
> drivers/net/dsa/qca8k.c | 8 ++++---- > drivers/net/dsa/qca8k.h | 33 ++++++++++++++++----------------- > 2 files changed, 20 insertions(+), 21 deletions(-) > > diff --git a/drivers/net/dsa/qca8k.c b/drivers/net/dsa/qca8k.c > index ee0dbf324268..8d059da5f0ca 100644 > --- a/drivers/net/dsa/qca8k.c > +++ b/drivers/net/dsa/qca8k.c > @@ -1685,11 +1685,11 @@ qca8k_phylink_mac_select_pcs(struct dsa_switch *ds, int port, > case PHY_INTERFACE_MODE_1000BASEX: > switch (port) { > case 0: > - pcs = &priv->pcs_port_0.pcs; > + pcs = &priv->ports_config.qpcs[QCA8K_CPU_PORT0].pcs; > break; > > case 6: > - pcs = &priv->pcs_port_6.pcs; > + pcs = &priv->ports_config.qpcs[QCA8K_CPU_PORT6].pcs; > break; > } > break; > @@ -2889,8 +2889,8 @@ qca8k_setup(struct dsa_switch *ds) > if (ret) > return ret; > > - qca8k_setup_pcs(priv, &priv->pcs_port_0, 0); > - qca8k_setup_pcs(priv, &priv->pcs_port_6, 6); > + qca8k_setup_pcs(priv, &priv->ports_config.qpcs[QCA8K_CPU_PORT0], 0); > + qca8k_setup_pcs(priv, &priv->ports_config.qpcs[QCA8K_CPU_PORT6], 6); > > /* Make sure MAC06 is disabled */ > ret = regmap_clear_bits(priv->regmap, QCA8K_REG_PORT0_PAD_CTRL, > diff --git a/drivers/net/dsa/qca8k.h b/drivers/net/dsa/qca8k.h > index f375627174c8..611dc2335dbe 100644 > --- a/drivers/net/dsa/qca8k.h > +++ b/drivers/net/dsa/qca8k.h > @@ -341,18 +341,24 @@ enum { > > struct qca8k_mgmt_eth_data { > struct completion rw_done; > - struct mutex mutex; /* Enforce one mdio read/write at time */ > + u32 data[4]; > bool ack; > u32 seq; > - u32 data[4]; > + struct mutex mutex; /* Enforce one mdio read/write at time */ > }; > > struct qca8k_mib_eth_data { > struct completion rw_done; > + u64 *data; /* pointer to ethtool data */ > + u8 req_port; > struct mutex mutex; /* Process one command at time */ > refcount_t port_parsed; /* Counter to track parsed port */ > - u8 req_port; > - u64 *data; /* pointer to ethtool data */ > +}; > + > +struct qca8k_pcs { > + struct phylink_pcs pcs; > + struct qca8k_priv *priv; > + int port; > }; > > struct qca8k_ports_config { > @@ -361,6 +367,7 @@ struct qca8k_ports_config { > bool sgmii_enable_pll; > u8 rgmii_rx_delay[QCA8K_NUM_CPU_PORTS]; /* 0: CPU port0, 1: CPU port6 */ > u8 rgmii_tx_delay[QCA8K_NUM_CPU_PORTS]; /* 0: CPU port0, 1: CPU port6 */ > + struct qca8k_pcs qpcs[QCA8K_NUM_CPU_PORTS]; > }; > > struct qca8k_mdio_cache { > @@ -376,13 +383,10 @@ struct qca8k_mdio_cache { > u16 hi; > }; > > -struct qca8k_pcs { > - struct phylink_pcs pcs; > - struct qca8k_priv *priv; > - int port; > -}; > - > struct qca8k_priv { > + struct net_device *mgmt_master; /* Track if mdio/mib Ethernet is available */ > + struct qca8k_mgmt_eth_data mgmt_eth_data; > + struct qca8k_mdio_cache mdio_cache; > u8 switch_id; > u8 switch_revision; > u8 mirror_rx; > @@ -396,15 +400,10 @@ struct qca8k_priv { > struct dsa_switch *ds; > struct mutex reg_mutex; > struct device *dev; > - struct dsa_switch_ops ops; > struct gpio_desc *reset_gpio; > - unsigned int port_mtu[QCA8K_NUM_PORTS]; > - struct net_device *mgmt_master; /* Track if mdio/mib Ethernet is available */ > - struct qca8k_mgmt_eth_data mgmt_eth_data; > + struct dsa_switch_ops ops; > struct qca8k_mib_eth_data mib_eth_data; > - struct qca8k_mdio_cache mdio_cache; > - struct qca8k_pcs pcs_port_0; > - struct qca8k_pcs pcs_port_6; > + unsigned int port_mtu[QCA8K_NUM_PORTS]; > }; > > struct qca8k_mib_desc { > -- > 2.34.1 >
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