* Re: [PATCH net-next] net: introduce netdevice gso_min_segs attribute
From: Amir Vadai @ 2014-10-06 6:41 UTC (permalink / raw)
To: Eric Dumazet, David S. Miller
Cc: Eric Dumazet, netdev, Yevgeny Petrilin, Or Gerlitz, Ido Shamay
In-Reply-To: <1412529087.11091.14.camel@edumazet-glaptop2.roam.corp.google.com>
On 10/5/2014 8:11 PM, Eric Dumazet wrote:
> From: Eric Dumazet <edumazet@google.com>
>
> Some TSO engines might have a too heavy setup cost, that impacts
> performance on hosts sending small bursts (2 MSS per packet).
>
> This patch adds a device gso_min_segs, allowing drivers to set
> a minimum segment size for TSO packets, according to the NIC
> performance.
>
> Tested on a mlx4 NIC, this allows to get a ~110% increase of
> throughput when sending 2 MSS per packet.
>
Amazing!
Shouldn't there be a netif_set_gso_min_size() too?
> Signed-off-by: Eric Dumazet <edumazet@google.com>
> ---
> mlx4 patch will be sent later, its a one liner.
>
> include/linux/netdevice.h | 4 +++-
> net/core/dev.c | 9 ++++++---
> 2 files changed, 9 insertions(+), 4 deletions(-)
>
> diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
> index 22d54b9b700d..2df86f50261c 100644
> --- a/include/linux/netdevice.h
> +++ b/include/linux/netdevice.h
> @@ -1416,6 +1416,8 @@ enum netdev_priv_flags {
> * @gso_max_size: Maximum size of generic segmentation offload
> * @gso_max_segs: Maximum number of segments that can be passed to the
> * NIC for GSO
> + * @gso_min_segs: Minimum number of segments that can be passed to the
> + * NIC for GSO
> *
> * @dcbnl_ops: Data Center Bridging netlink ops
> * @num_tc: Number of traffic classes in the net device
> @@ -1666,7 +1668,7 @@ struct net_device {
> unsigned int gso_max_size;
> #define GSO_MAX_SEGS 65535
> u16 gso_max_segs;
> -
> + u16 gso_min_segs;
> #ifdef CONFIG_DCB
> const struct dcbnl_rtnl_ops *dcbnl_ops;
> #endif
> diff --git a/net/core/dev.c b/net/core/dev.c
> index 1a90530f83ff..16e8ebbd3316 100644
> --- a/net/core/dev.c
> +++ b/net/core/dev.c
> @@ -2567,10 +2567,12 @@ static netdev_features_t harmonize_features(struct sk_buff *skb,
>
> netdev_features_t netif_skb_features(struct sk_buff *skb)
> {
> + const struct net_device *dev = skb->dev;
> + netdev_features_t features = dev->features;
> + u16 gso_segs = skb_shinfo(skb)->gso_segs;
> __be16 protocol = skb->protocol;
> - netdev_features_t features = skb->dev->features;
>
> - if (skb_shinfo(skb)->gso_segs > skb->dev->gso_max_segs)
> + if (gso_segs > dev->gso_max_segs || gso_segs < dev->gso_min_segs)
> features &= ~NETIF_F_GSO_MASK;
>
> if (protocol == htons(ETH_P_8021Q) || protocol == htons(ETH_P_8021AD)) {
> @@ -2581,7 +2583,7 @@ netdev_features_t netif_skb_features(struct sk_buff *skb)
> }
>
> features = netdev_intersect_features(features,
> - skb->dev->vlan_features |
> + dev->vlan_features |
> NETIF_F_HW_VLAN_CTAG_TX |
> NETIF_F_HW_VLAN_STAG_TX);
>
> @@ -6658,6 +6660,7 @@ struct net_device *alloc_netdev_mqs(int sizeof_priv, const char *name,
>
> dev->gso_max_size = GSO_MAX_SIZE;
> dev->gso_max_segs = GSO_MAX_SEGS;
> + dev->gso_min_segs = 0;
>
> INIT_LIST_HEAD(&dev->napi_list);
> INIT_LIST_HEAD(&dev->unreg_list);
>
>
^ permalink raw reply
* RE: [net-next v3 20/29] fm10k: Add support for netdev offloads
From: Sathya Perla @ 2014-10-06 6:19 UTC (permalink / raw)
To: Duyck, Alexander H, Or Gerlitz, Kirsher, Jeffrey T
Cc: David Miller, Linux Netdev List, nhorman@redhat.com,
sassmann@redhat.com, jogreene@redhat.com, Tom Herbert
In-Reply-To: <D29CC2C771335549BDCBB23A2B92BE379C7F84CE@ORSMSX110.amr.corp.intel.com>
> -----Original Message-----
> From: netdev-owner@vger.kernel.org [mailto:netdev-
> owner@vger.kernel.org] On Behalf Of Duyck, Alexander H
...
> adds
> > > >> support for basic offloads including TSO, Tx checksum, Rx checksum,
> > > >> Rx hash, and the same features applied to VXLAN/NVGRE
> > > tunnels.
> > > >
> > > >> --- a/drivers/net/ethernet/intel/fm10k/fm10k_main.c
> > > >> +++ b/drivers/net/ethernet/intel/fm10k/fm10k_main.c
> > > > [...]
> > > >> +#define VXLAN_HLEN (sizeof(struct udphdr) + 8) static struct
> > > >> +ethhdr *fm10k_port_is_vxlan(struct sk_buff *skb) {
> > > >> + struct fm10k_intfc *interface = netdev_priv(skb->dev);
> > > >> + struct fm10k_vxlan_port *vxlan_port;
> > > >> +
> > > >> + /* we can only offload a vxlan if we recognize it as such */
> > > >> + vxlan_port = list_first_entry_or_null(&interface->vxlan_port,
> > > >> + struct
> > > >> + fm10k_vxlan_port, list);
> > > >> +
> > > >> + if (!vxlan_port)
> > > >> + return NULL;
> > > >> + if (vxlan_port->port != udp_hdr(skb)->dest)
> > > >> + return NULL;
> > > >> +
> > > >> + /* return offset of udp_hdr plus 8 bytes for VXLAN header */
> > > >> + return (struct ethhdr *)(skb_transport_header(skb) +
> > > >> +VXLAN_HLEN); }
> > > >> +
> > ...
> > >
> > > >> +static int fm10k_tso(struct fm10k_ring *tx_ring,
> > > >> + struct fm10k_tx_buffer *first) {
> > > >> + struct sk_buff *skb = first->skb;
> > > >> + struct fm10k_tx_desc *tx_desc;
> > > >> + unsigned char *th;
> > > >> + u8 hdrlen;
> > > >> +
> > > >> + if (skb->ip_summed != CHECKSUM_PARTIAL)
> > > >> + return 0;
> > > >> +
> > > >> + if (!skb_is_gso(skb))
> > > >> + return 0;
> > > >> +
> > > >> + /* compute header lengths */
> > > >> + if (skb->encapsulation) {
> > > >> + if (!fm10k_tx_encap_offload(skb))
> > > >> + goto err_vxlan;
> > > >> + th = skb_inner_transport_header(skb);
> > > >> + } else {
> > > >> + th = skb_transport_header(skb);
> > > >> + }
> > > >> +
> > > >> + /* compute offset from SOF to transport header and add
> > > >> + header len
> > > */
> > > >> + hdrlen = (th - skb->data) + (((struct tcphdr *)th)->doff <<
> > > >> + 2);
> > > >> +
> > > >> + first->tx_flags |= FM10K_TX_FLAGS_CSUM;
> > > >> +
> > > >> + /* update gso size and bytecount with header size */
> > > >> + first->gso_segs = skb_shinfo(skb)->gso_segs;
> > > >> + first->bytecount += (first->gso_segs - 1) * hdrlen;
> > > >> +
> > > >> + /* populate Tx descriptor header size and mss */
> > > >> + tx_desc = FM10K_TX_DESC(tx_ring, tx_ring->next_to_use);
> > > >> + tx_desc->hdrlen = hdrlen;
> > > >> + tx_desc->mss = cpu_to_le16(skb_shinfo(skb)->gso_size);
> > > >> +
> > > >> + return 1;
> > > >> +err_vxlan:
> > > >> + tx_ring->netdev->features &= ~NETIF_F_GSO_UDP_TUNNEL;
> > > >> + if (!net_ratelimit())
> > > >> + netdev_err(tx_ring->netdev,
> > > >> + "TSO requested for unsupported tunnel,
> > > >> +disabling
> > > offload\n");
> > > >> + return -1;
> > > >> +}
> > > >
> > > > why? if TSO was requested for some packet the driver can't do, you
> > > > disable
> > > GSO
> > > > for udp tunnels for any future packets too? maybe just disable it
> > > > permanently till you feel safer to run under the current stack?
> > >
> > > That is essentially what I am doing. If the user wants they can turn
> > > the feature back on via ethtool, but there is no point in having it on
> > > if the device itself cannot support the packets that are coming through.
> > >
> >
> > To turn off the offload, shouldn't you be using netdev_update_features()
> > (->ndo_fix_features()) instead of directly flipping bits in netdev->features?
>
> Why? That would just be me calling my own ndo operation wouldn't it, since
> I am changing the features of the device covered by this driver.
I guess it would be to ensure that all dependencies are resolved and a
FEAT_CHANGE notification is issued.
Documentation/networking/netdev-features.txt says the following:
" When current feature set (netdev->features) is to be changed, new set
is calculated and filtered by calling ndo_fix_features callback
and netdev_fix_features()."
" A driver that wants to trigger recalculation must do so by calling
netdev_update_features() while holding rtnl_lock. This should not be done
from ndo_*_features callbacks. netdev->features should not be modified by
driver except by means of ndo_fix_features callback."
^ permalink raw reply
* [PATCH net-next V1 11/14] net/mlx4_en: tx_info->ts_requested was not cleared
From: Amir Vadai @ 2014-10-06 6:16 UTC (permalink / raw)
To: David S. Miller, Eric Dumazet
Cc: netdev, Yevgeny Petrilin, Or Gerlitz, Ido Shamay, Amir Vadai
In-Reply-To: <1412576163-7224-1-git-send-email-amirv@mellanox.com>
From: Eric Dumazet <edumazet@google.com>
Properly clear tx_info->ts_requested
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Amir Vadai <amirv@mellanox.com>
---
drivers/net/ethernet/mellanox/mlx4/en_tx.c | 1 +
1 file changed, 1 insertion(+)
diff --git a/drivers/net/ethernet/mellanox/mlx4/en_tx.c b/drivers/net/ethernet/mellanox/mlx4/en_tx.c
index e00841a..2c03b55 100644
--- a/drivers/net/ethernet/mellanox/mlx4/en_tx.c
+++ b/drivers/net/ethernet/mellanox/mlx4/en_tx.c
@@ -837,6 +837,7 @@ netdev_tx_t mlx4_en_xmit(struct sk_buff *skb, struct net_device *dev)
* For timestamping add flag to skb_shinfo and
* set flag for further reference
*/
+ tx_info->ts_requested = 0;
if (unlikely(ring->hwtstamp_tx_type == HWTSTAMP_TX_ON &&
shinfo->tx_flags & SKBTX_HW_TSTAMP)) {
shinfo->tx_flags |= SKBTX_IN_PROGRESS;
--
1.8.3.1
^ permalink raw reply related
* [PATCH net-next V1 13/14] ethtool: Ethtool parameter to dynamically change tx_copybreak
From: Amir Vadai @ 2014-10-06 6:16 UTC (permalink / raw)
To: David S. Miller, Eric Dumazet
Cc: netdev, Yevgeny Petrilin, Or Gerlitz, Ido Shamay, Amir Vadai
In-Reply-To: <1412576163-7224-1-git-send-email-amirv@mellanox.com>
From: Eric Dumazet <edumazet@google.com>
Use new ethtool [sg]et_tunable() to set tx_copybread (inline threshold)
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Amir Vadai <amirv@mellanox.com>
---
include/uapi/linux/ethtool.h | 1 +
net/core/ethtool.c | 1 +
2 files changed, 2 insertions(+)
diff --git a/include/uapi/linux/ethtool.h b/include/uapi/linux/ethtool.h
index 7a364f2..99b4305 100644
--- a/include/uapi/linux/ethtool.h
+++ b/include/uapi/linux/ethtool.h
@@ -212,6 +212,7 @@ struct ethtool_value {
enum tunable_id {
ETHTOOL_ID_UNSPEC,
ETHTOOL_RX_COPYBREAK,
+ ETHTOOL_TX_COPYBREAK,
};
enum tunable_type_id {
diff --git a/net/core/ethtool.c b/net/core/ethtool.c
index 27e61b8..1600aa2 100644
--- a/net/core/ethtool.c
+++ b/net/core/ethtool.c
@@ -1625,6 +1625,7 @@ static int ethtool_tunable_valid(const struct ethtool_tunable *tuna)
{
switch (tuna->id) {
case ETHTOOL_RX_COPYBREAK:
+ case ETHTOOL_TX_COPYBREAK:
if (tuna->len != sizeof(u32) ||
tuna->type_id != ETHTOOL_TUNABLE_U32)
return -EINVAL;
--
1.8.3.1
^ permalink raw reply related
* [PATCH net-next V1 09/14] net/mlx4_en: Use local var in tx flow for skb_shinfo(skb)
From: Amir Vadai @ 2014-10-06 6:15 UTC (permalink / raw)
To: David S. Miller, Eric Dumazet
Cc: netdev, Yevgeny Petrilin, Or Gerlitz, Ido Shamay, Amir Vadai
In-Reply-To: <1412576163-7224-1-git-send-email-amirv@mellanox.com>
From: Eric Dumazet <edumazet@google.com>
Acces skb_shinfo(skb) once in tx flow.
Also, rename @i variable to @i_frag to avoid confusion, as the "goto
tx_drop_unmap;" relied on this @i variable.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Amir Vadai <amirv@mellanox.com>
---
drivers/net/ethernet/mellanox/mlx4/en_tx.c | 62 +++++++++++++++++-------------
1 file changed, 36 insertions(+), 26 deletions(-)
diff --git a/drivers/net/ethernet/mellanox/mlx4/en_tx.c b/drivers/net/ethernet/mellanox/mlx4/en_tx.c
index 4b018ce..aa05b09 100644
--- a/drivers/net/ethernet/mellanox/mlx4/en_tx.c
+++ b/drivers/net/ethernet/mellanox/mlx4/en_tx.c
@@ -532,13 +532,14 @@ static struct mlx4_en_tx_desc *mlx4_en_bounce_to_desc(struct mlx4_en_priv *priv,
}
static bool is_inline(int inline_thold, const struct sk_buff *skb,
+ const struct skb_shared_info *shinfo,
void **pfrag)
{
void *ptr;
if (inline_thold && !skb_is_gso(skb) && skb->len <= inline_thold) {
- if (skb_shinfo(skb)->nr_frags == 1) {
- ptr = skb_frag_address_safe(&skb_shinfo(skb)->frags[0]);
+ if (shinfo->nr_frags == 1) {
+ ptr = skb_frag_address_safe(&shinfo->frags[0]);
if (unlikely(!ptr))
return 0;
@@ -546,7 +547,7 @@ static bool is_inline(int inline_thold, const struct sk_buff *skb,
*pfrag = ptr;
return 1;
- } else if (unlikely(skb_shinfo(skb)->nr_frags))
+ } else if (unlikely(shinfo->nr_frags))
return 0;
else
return 1;
@@ -567,18 +568,19 @@ static int inline_size(const struct sk_buff *skb)
}
static int get_real_size(const struct sk_buff *skb,
+ const struct skb_shared_info *shinfo,
struct net_device *dev,
int *lso_header_size)
{
struct mlx4_en_priv *priv = netdev_priv(dev);
int real_size;
- if (skb_is_gso(skb)) {
+ if (shinfo->gso_size) {
if (skb->encapsulation)
*lso_header_size = (skb_inner_transport_header(skb) - skb->data) + inner_tcp_hdrlen(skb);
else
*lso_header_size = skb_transport_offset(skb) + tcp_hdrlen(skb);
- real_size = CTRL_SIZE + skb_shinfo(skb)->nr_frags * DS_SIZE +
+ real_size = CTRL_SIZE + shinfo->nr_frags * DS_SIZE +
ALIGN(*lso_header_size + 4, DS_SIZE);
if (unlikely(*lso_header_size != skb_headlen(skb))) {
/* We add a segment for the skb linear buffer only if
@@ -593,8 +595,8 @@ static int get_real_size(const struct sk_buff *skb,
}
} else {
*lso_header_size = 0;
- if (!is_inline(priv->prof->inline_thold, skb, NULL))
- real_size = CTRL_SIZE + (skb_shinfo(skb)->nr_frags + 1) * DS_SIZE;
+ if (!is_inline(priv->prof->inline_thold, skb, shinfo, NULL))
+ real_size = CTRL_SIZE + (shinfo->nr_frags + 1) * DS_SIZE;
else
real_size = inline_size(skb);
}
@@ -604,6 +606,7 @@ static int get_real_size(const struct sk_buff *skb,
static void build_inline_wqe(struct mlx4_en_tx_desc *tx_desc,
const struct sk_buff *skb,
+ const struct skb_shared_info *shinfo,
int real_size, u16 *vlan_tag,
int tx_ind, void *fragptr)
{
@@ -619,9 +622,9 @@ static void build_inline_wqe(struct mlx4_en_tx_desc *tx_desc,
MIN_PKT_LEN - skb->len);
}
skb_copy_from_linear_data(skb, inl + 1, skb_headlen(skb));
- if (skb_shinfo(skb)->nr_frags)
+ if (shinfo->nr_frags)
memcpy(((void *)(inl + 1)) + skb_headlen(skb), fragptr,
- skb_frag_size(&skb_shinfo(skb)->frags[0]));
+ skb_frag_size(&shinfo->frags[0]));
} else {
inl->byte_count = cpu_to_be32(1 << 31 | spc);
@@ -639,9 +642,10 @@ static void build_inline_wqe(struct mlx4_en_tx_desc *tx_desc,
inl = (void *) (inl + 1) + spc;
skb_copy_from_linear_data_offset(skb, spc, inl + 1,
skb_headlen(skb) - spc);
- if (skb_shinfo(skb)->nr_frags)
+ if (shinfo->nr_frags)
memcpy(((void *)(inl + 1)) + skb_headlen(skb) - spc,
- fragptr, skb_frag_size(&skb_shinfo(skb)->frags[0]));
+ fragptr,
+ skb_frag_size(&shinfo->frags[0]));
}
wmb();
@@ -673,6 +677,7 @@ static void mlx4_bf_copy(void __iomem *dst, const void *src,
netdev_tx_t mlx4_en_xmit(struct sk_buff *skb, struct net_device *dev)
{
+ struct skb_shared_info *shinfo = skb_shinfo(skb);
struct mlx4_en_priv *priv = netdev_priv(dev);
struct device *ddev = priv->ddev;
struct mlx4_en_tx_ring *ring;
@@ -686,7 +691,7 @@ netdev_tx_t mlx4_en_xmit(struct sk_buff *skb, struct net_device *dev)
u32 index, bf_index;
__be32 op_own;
u16 vlan_tag = 0;
- int i;
+ int i_frag;
int lso_header_size;
void *fragptr;
bool bounce = false;
@@ -702,7 +707,7 @@ netdev_tx_t mlx4_en_xmit(struct sk_buff *skb, struct net_device *dev)
/* fetch ring->cons far ahead before needing it to avoid stall */
ring_cons = ACCESS_ONCE(ring->cons);
- real_size = get_real_size(skb, dev, &lso_header_size);
+ real_size = get_real_size(skb, shinfo, dev, &lso_header_size);
if (unlikely(!real_size))
goto tx_drop;
@@ -776,21 +781,22 @@ netdev_tx_t mlx4_en_xmit(struct sk_buff *skb, struct net_device *dev)
tx_info->data_offset = (void *)data - (void *)tx_desc;
tx_info->linear = (lso_header_size < skb_headlen(skb) &&
- !is_inline(ring->inline_thold, skb, NULL)) ? 1 : 0;
+ !is_inline(ring->inline_thold, skb, shinfo, NULL)) ? 1 : 0;
- tx_info->nr_maps = skb_shinfo(skb)->nr_frags + tx_info->linear;
+ tx_info->nr_maps = shinfo->nr_frags + tx_info->linear;
data += tx_info->nr_maps - 1;
- if (is_inline(ring->inline_thold, skb, &fragptr)) {
+ if (is_inline(ring->inline_thold, skb, shinfo, &fragptr)) {
tx_info->inl = 1;
} else {
dma_addr_t dma = 0;
u32 byte_count = 0;
/* Map fragments if any */
- for (i = skb_shinfo(skb)->nr_frags - 1; i >= 0; i--) {
+ for (i_frag = shinfo->nr_frags - 1; i_frag >= 0; i_frag--) {
const struct skb_frag_struct *frag;
- frag = &skb_shinfo(skb)->frags[i];
+
+ frag = &shinfo->frags[i_frag];
byte_count = skb_frag_size(frag);
dma = skb_frag_dma_map(ddev, frag,
0, byte_count,
@@ -831,8 +837,8 @@ netdev_tx_t mlx4_en_xmit(struct sk_buff *skb, struct net_device *dev)
* set flag for further reference
*/
if (unlikely(ring->hwtstamp_tx_type == HWTSTAMP_TX_ON &&
- skb_shinfo(skb)->tx_flags & SKBTX_HW_TSTAMP)) {
- skb_shinfo(skb)->tx_flags |= SKBTX_IN_PROGRESS;
+ shinfo->tx_flags & SKBTX_HW_TSTAMP)) {
+ shinfo->tx_flags |= SKBTX_IN_PROGRESS;
tx_info->ts_requested = 1;
}
@@ -858,6 +864,8 @@ netdev_tx_t mlx4_en_xmit(struct sk_buff *skb, struct net_device *dev)
/* Handle LSO (TSO) packets */
if (lso_header_size) {
+ int i;
+
/* Mark opcode as LSO */
op_own = cpu_to_be32(MLX4_OPCODE_LSO | (1 << 6)) |
((ring->prod & ring->size) ?
@@ -865,15 +873,16 @@ netdev_tx_t mlx4_en_xmit(struct sk_buff *skb, struct net_device *dev)
/* Fill in the LSO prefix */
tx_desc->lso.mss_hdr_size = cpu_to_be32(
- skb_shinfo(skb)->gso_size << 16 | lso_header_size);
+ shinfo->gso_size << 16 | lso_header_size);
/* Copy headers;
* note that we already verified that it is linear */
memcpy(tx_desc->lso.header, skb->data, lso_header_size);
ring->tso_packets++;
- i = ((skb->len - lso_header_size) / skb_shinfo(skb)->gso_size) +
- !!((skb->len - lso_header_size) % skb_shinfo(skb)->gso_size);
+
+ i = ((skb->len - lso_header_size) / shinfo->gso_size) +
+ !!((skb->len - lso_header_size) % shinfo->gso_size);
tx_info->nr_bytes = skb->len + (i - 1) * lso_header_size;
ring->packets += i;
} else {
@@ -889,7 +898,8 @@ netdev_tx_t mlx4_en_xmit(struct sk_buff *skb, struct net_device *dev)
AVG_PERF_COUNTER(priv->pstats.tx_pktsz_avg, skb->len);
if (tx_info->inl) {
- build_inline_wqe(tx_desc, skb, real_size, &vlan_tag, tx_ind, fragptr);
+ build_inline_wqe(tx_desc, skb, shinfo, real_size, &vlan_tag,
+ tx_ind, fragptr);
tx_info->inl = 1;
}
@@ -958,8 +968,8 @@ netdev_tx_t mlx4_en_xmit(struct sk_buff *skb, struct net_device *dev)
tx_drop_unmap:
en_err(priv, "DMA mapping error\n");
- for (i++; i < skb_shinfo(skb)->nr_frags; i++) {
- data++;
+ while (++i_frag < shinfo->nr_frags) {
+ ++data;
dma_unmap_page(ddev, (dma_addr_t) be64_to_cpu(data->addr),
be32_to_cpu(data->byte_count),
PCI_DMA_TODEVICE);
--
1.8.3.1
^ permalink raw reply related
* [PATCH net-next V1 07/14] net/mlx4_en: Avoid false sharing in mlx4_en_en_process_tx_cq()
From: Amir Vadai @ 2014-10-06 6:15 UTC (permalink / raw)
To: David S. Miller, Eric Dumazet
Cc: netdev, Yevgeny Petrilin, Or Gerlitz, Ido Shamay, Amir Vadai
In-Reply-To: <1412576163-7224-1-git-send-email-amirv@mellanox.com>
From: Eric Dumazet <edumazet@google.com>
mlx4_en_process_tx_cq() carefully fetches and writes ring->last_nr_txbb
and ring->cons only one time to avoid false sharing
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Amir Vadai <amirv@mellanox.com>
---
drivers/net/ethernet/mellanox/mlx4/en_tx.c | 22 +++++++++++++++-------
1 file changed, 15 insertions(+), 7 deletions(-)
diff --git a/drivers/net/ethernet/mellanox/mlx4/en_tx.c b/drivers/net/ethernet/mellanox/mlx4/en_tx.c
index 9328e6e..63e1f24 100644
--- a/drivers/net/ethernet/mellanox/mlx4/en_tx.c
+++ b/drivers/net/ethernet/mellanox/mlx4/en_tx.c
@@ -387,6 +387,8 @@ static bool mlx4_en_process_tx_cq(struct net_device *dev,
u64 timestamp = 0;
int done = 0;
int budget = priv->tx_work_limit;
+ u32 last_nr_txbb;
+ u32 ring_cons;
if (!priv->port_up)
return true;
@@ -394,7 +396,9 @@ static bool mlx4_en_process_tx_cq(struct net_device *dev,
prefetchw(&ring->tx_queue->dql.limit);
index = cons_index & size_mask;
cqe = mlx4_en_get_cqe(buf, index, priv->cqe_size) + factor;
- ring_index = ring->cons & size_mask;
+ last_nr_txbb = ACCESS_ONCE(ring->last_nr_txbb);
+ ring_cons = ACCESS_ONCE(ring->cons);
+ ring_index = ring_cons & size_mask;
stamp_index = ring_index;
/* Process all completed CQEs */
@@ -419,19 +423,19 @@ static bool mlx4_en_process_tx_cq(struct net_device *dev,
new_index = be16_to_cpu(cqe->wqe_index) & size_mask;
do {
- txbbs_skipped += ring->last_nr_txbb;
- ring_index = (ring_index + ring->last_nr_txbb) & size_mask;
+ txbbs_skipped += last_nr_txbb;
+ ring_index = (ring_index + last_nr_txbb) & size_mask;
if (ring->tx_info[ring_index].ts_requested)
timestamp = mlx4_en_get_cqe_ts(cqe);
/* free next descriptor */
- ring->last_nr_txbb = mlx4_en_free_tx_desc(
+ last_nr_txbb = mlx4_en_free_tx_desc(
priv, ring, ring_index,
- !!((ring->cons + txbbs_skipped) &
+ !!((ring_cons + txbbs_skipped) &
ring->size), timestamp);
mlx4_en_stamp_wqe(priv, ring, stamp_index,
- !!((ring->cons + txbbs_stamp) &
+ !!((ring_cons + txbbs_stamp) &
ring->size));
stamp_index = ring_index;
txbbs_stamp = txbbs_skipped;
@@ -452,7 +456,11 @@ static bool mlx4_en_process_tx_cq(struct net_device *dev,
mcq->cons_index = cons_index;
mlx4_cq_set_ci(mcq);
wmb();
- ring->cons += txbbs_skipped;
+
+ /* we want to dirty this cache line once */
+ ACCESS_ONCE(ring->last_nr_txbb) = last_nr_txbb;
+ ACCESS_ONCE(ring->cons) = ring_cons + txbbs_skipped;
+
netdev_tx_completed_queue(ring->tx_queue, packets, bytes);
/*
--
1.8.3.1
^ permalink raw reply related
* [PATCH net-next V1 04/14] net/mlx4_en: tx_info allocated with kmalloc() instead of vmalloc()
From: Amir Vadai @ 2014-10-06 6:15 UTC (permalink / raw)
To: David S. Miller, Eric Dumazet
Cc: netdev, Yevgeny Petrilin, Or Gerlitz, Ido Shamay, Amir Vadai
In-Reply-To: <1412576163-7224-1-git-send-email-amirv@mellanox.com>
From: Eric Dumazet <edumazet@google.com>
Try to allocate using kmalloc_node() first, only on failure use
vmalloc()
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Amir Vadai <amirv@mellanox.com>
---
drivers/net/ethernet/mellanox/mlx4/en_tx.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/drivers/net/ethernet/mellanox/mlx4/en_tx.c b/drivers/net/ethernet/mellanox/mlx4/en_tx.c
index 3ea17f9..02ade59 100644
--- a/drivers/net/ethernet/mellanox/mlx4/en_tx.c
+++ b/drivers/net/ethernet/mellanox/mlx4/en_tx.c
@@ -68,7 +68,7 @@ int mlx4_en_create_tx_ring(struct mlx4_en_priv *priv,
ring->inline_thold = priv->prof->inline_thold;
tmp = size * sizeof(struct mlx4_en_tx_info);
- ring->tx_info = vmalloc_node(tmp, node);
+ ring->tx_info = kmalloc_node(tmp, GFP_KERNEL | __GFP_NOWARN, node);
if (!ring->tx_info) {
ring->tx_info = vmalloc(tmp);
if (!ring->tx_info) {
@@ -151,7 +151,7 @@ err_bounce:
kfree(ring->bounce_buf);
ring->bounce_buf = NULL;
err_info:
- vfree(ring->tx_info);
+ kvfree(ring->tx_info);
ring->tx_info = NULL;
err_ring:
kfree(ring);
@@ -174,7 +174,7 @@ void mlx4_en_destroy_tx_ring(struct mlx4_en_priv *priv,
mlx4_free_hwq_res(mdev->dev, &ring->wqres, ring->buf_size);
kfree(ring->bounce_buf);
ring->bounce_buf = NULL;
- vfree(ring->tx_info);
+ kvfree(ring->tx_info);
ring->tx_info = NULL;
kfree(ring);
*pring = NULL;
--
1.8.3.1
^ permalink raw reply related
* [PATCH net-next V1 02/14] net/mlx4_en: Align tx path structures to cache lines
From: Amir Vadai @ 2014-10-06 6:15 UTC (permalink / raw)
To: David S. Miller, Eric Dumazet
Cc: netdev, Yevgeny Petrilin, Or Gerlitz, Ido Shamay, Amir Vadai
In-Reply-To: <1412576163-7224-1-git-send-email-amirv@mellanox.com>
From: Eric Dumazet <edumazet@google.com>
Reorganize struct mlx4_en_tx_ring to have:
- One cache line containing last_nr_txbb & cons & wake_queue, used by tx
completion.
- One cache line containing fields dirtied by mlx4_en_xmit()
- Following part is read mostly and shared by cpus.
Align struct mlx4_en_tx_info to a cache line
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Amir Vadai <amirv@mellanox.com>
---
drivers/net/ethernet/mellanox/mlx4/mlx4_en.h | 86 +++++++++++++++-------------
1 file changed, 46 insertions(+), 40 deletions(-)
diff --git a/drivers/net/ethernet/mellanox/mlx4/mlx4_en.h b/drivers/net/ethernet/mellanox/mlx4/mlx4_en.h
index e54b653..b7bde95 100644
--- a/drivers/net/ethernet/mellanox/mlx4/mlx4_en.h
+++ b/drivers/net/ethernet/mellanox/mlx4/mlx4_en.h
@@ -216,13 +216,13 @@ enum cq_type {
struct mlx4_en_tx_info {
struct sk_buff *skb;
- u32 nr_txbb;
- u32 nr_bytes;
- u8 linear;
- u8 data_offset;
- u8 inl;
- u8 ts_requested;
-};
+ u32 nr_txbb;
+ u32 nr_bytes;
+ u8 linear;
+ u8 data_offset;
+ u8 inl;
+ u8 ts_requested;
+} ____cacheline_aligned_in_smp;
#define MLX4_EN_BIT_DESC_OWN 0x80000000
@@ -253,40 +253,46 @@ struct mlx4_en_rx_alloc {
};
struct mlx4_en_tx_ring {
+ /* cache line used and dirtied in tx completion
+ * (mlx4_en_free_tx_buf())
+ */
+ u32 last_nr_txbb;
+ u32 cons;
+ unsigned long wake_queue;
+
+ /* cache line used and dirtied in mlx4_en_xmit() */
+ u32 prod ____cacheline_aligned_in_smp;
+ unsigned long bytes;
+ unsigned long packets;
+ unsigned long tx_csum;
+ unsigned long tso_packets;
+ unsigned long xmit_more;
+ struct mlx4_bf bf;
+ unsigned long queue_stopped;
+
+ /* Following part should be mostly read */
+ cpumask_t affinity_mask;
+ struct mlx4_qp qp;
struct mlx4_hwq_resources wqres;
- u32 size ; /* number of TXBBs */
- u32 size_mask;
- u16 stride;
- u16 cqn; /* index of port CQ associated with this ring */
- u32 prod;
- u32 cons;
- u32 buf_size;
- u32 doorbell_qpn;
- void *buf;
- struct mlx4_en_tx_info *tx_info;
- u8 *bounce_buf;
- u8 queue_index;
- cpumask_t affinity_mask;
- u32 last_nr_txbb;
- struct mlx4_qp qp;
- struct mlx4_qp_context context;
- int qpn;
- enum mlx4_qp_state qp_state;
- struct mlx4_srq dummy;
- unsigned long bytes;
- unsigned long packets;
- unsigned long tx_csum;
- unsigned long queue_stopped;
- unsigned long wake_queue;
- unsigned long tso_packets;
- unsigned long xmit_more;
- struct mlx4_bf bf;
- bool bf_enabled;
- bool bf_alloced;
- struct netdev_queue *tx_queue;
- int hwtstamp_tx_type;
- int inline_thold;
-};
+ u32 size; /* number of TXBBs */
+ u32 size_mask;
+ u16 stride;
+ u16 cqn; /* index of port CQ associated with this ring */
+ u32 buf_size;
+ u32 doorbell_qpn;
+ void *buf;
+ struct mlx4_en_tx_info *tx_info;
+ u8 *bounce_buf;
+ struct mlx4_qp_context context;
+ int qpn;
+ enum mlx4_qp_state qp_state;
+ u8 queue_index;
+ bool bf_enabled;
+ bool bf_alloced;
+ struct netdev_queue *tx_queue;
+ int hwtstamp_tx_type;
+ int inline_thold;
+} ____cacheline_aligned_in_smp;
struct mlx4_en_rx_desc {
/* actual number of entries depends on rx ring stride */
--
1.8.3.1
^ permalink raw reply related
* [PATCH net-next V1 12/14] net/mlx4_en: Enable the compiler to make is_inline() inlined
From: Amir Vadai @ 2014-10-06 6:16 UTC (permalink / raw)
To: David S. Miller, Eric Dumazet
Cc: netdev, Yevgeny Petrilin, Or Gerlitz, Ido Shamay, Amir Vadai
In-Reply-To: <1412576163-7224-1-git-send-email-amirv@mellanox.com>
From: Eric Dumazet <edumazet@google.com>
Reorganize code to call is_inline() once, so compiler can inline it
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Amir Vadai <amirv@mellanox.com>
---
drivers/net/ethernet/mellanox/mlx4/en_tx.c | 67 +++++++++++++++++-------------
1 file changed, 38 insertions(+), 29 deletions(-)
diff --git a/drivers/net/ethernet/mellanox/mlx4/en_tx.c b/drivers/net/ethernet/mellanox/mlx4/en_tx.c
index 2c03b55..f0080c5 100644
--- a/drivers/net/ethernet/mellanox/mlx4/en_tx.c
+++ b/drivers/net/ethernet/mellanox/mlx4/en_tx.c
@@ -531,29 +531,32 @@ static struct mlx4_en_tx_desc *mlx4_en_bounce_to_desc(struct mlx4_en_priv *priv,
return ring->buf + index * TXBB_SIZE;
}
+/* Decide if skb can be inlined in tx descriptor to avoid dma mapping
+ *
+ * It seems strange we do not simply use skb_copy_bits().
+ * This would allow to inline all skbs iff skb->len <= inline_thold
+ *
+ * Note that caller already checked skb was not a gso packet
+ */
static bool is_inline(int inline_thold, const struct sk_buff *skb,
const struct skb_shared_info *shinfo,
void **pfrag)
{
void *ptr;
- if (inline_thold && !skb_is_gso(skb) && skb->len <= inline_thold) {
- if (shinfo->nr_frags == 1) {
- ptr = skb_frag_address_safe(&shinfo->frags[0]);
- if (unlikely(!ptr))
- return 0;
-
- if (pfrag)
- *pfrag = ptr;
+ if (skb->len > inline_thold || !inline_thold)
+ return false;
- return 1;
- } else if (unlikely(shinfo->nr_frags))
- return 0;
- else
- return 1;
+ if (shinfo->nr_frags == 1) {
+ ptr = skb_frag_address_safe(&shinfo->frags[0]);
+ if (unlikely(!ptr))
+ return false;
+ *pfrag = ptr;
+ return true;
}
-
- return 0;
+ if (shinfo->nr_frags)
+ return false;
+ return true;
}
static int inline_size(const struct sk_buff *skb)
@@ -570,12 +573,15 @@ static int inline_size(const struct sk_buff *skb)
static int get_real_size(const struct sk_buff *skb,
const struct skb_shared_info *shinfo,
struct net_device *dev,
- int *lso_header_size)
+ int *lso_header_size,
+ bool *inline_ok,
+ void **pfrag)
{
struct mlx4_en_priv *priv = netdev_priv(dev);
int real_size;
if (shinfo->gso_size) {
+ *inline_ok = false;
if (skb->encapsulation)
*lso_header_size = (skb_inner_transport_header(skb) - skb->data) + inner_tcp_hdrlen(skb);
else
@@ -595,10 +601,14 @@ static int get_real_size(const struct sk_buff *skb,
}
} else {
*lso_header_size = 0;
- if (!is_inline(priv->prof->inline_thold, skb, shinfo, NULL))
- real_size = CTRL_SIZE + (shinfo->nr_frags + 1) * DS_SIZE;
- else
+ *inline_ok = is_inline(priv->prof->inline_thold, skb,
+ shinfo, pfrag);
+
+ if (*inline_ok)
real_size = inline_size(skb);
+ else
+ real_size = CTRL_SIZE +
+ (shinfo->nr_frags + 1) * DS_SIZE;
}
return real_size;
@@ -694,9 +704,10 @@ netdev_tx_t mlx4_en_xmit(struct sk_buff *skb, struct net_device *dev)
u16 vlan_tag = 0;
int i_frag;
int lso_header_size;
- void *fragptr;
+ void *fragptr = NULL;
bool bounce = false;
bool send_doorbell;
+ bool inline_ok;
u32 ring_cons;
if (!priv->port_up)
@@ -708,7 +719,8 @@ netdev_tx_t mlx4_en_xmit(struct sk_buff *skb, struct net_device *dev)
/* fetch ring->cons far ahead before needing it to avoid stall */
ring_cons = ACCESS_ONCE(ring->cons);
- real_size = get_real_size(skb, shinfo, dev, &lso_header_size);
+ real_size = get_real_size(skb, shinfo, dev, &lso_header_size,
+ &inline_ok, &fragptr);
if (unlikely(!real_size))
goto tx_drop;
@@ -781,15 +793,15 @@ netdev_tx_t mlx4_en_xmit(struct sk_buff *skb, struct net_device *dev)
/* valid only for none inline segments */
tx_info->data_offset = (void *)data - (void *)tx_desc;
+ tx_info->inl = inline_ok;
+
tx_info->linear = (lso_header_size < skb_headlen(skb) &&
- !is_inline(ring->inline_thold, skb, shinfo, NULL)) ? 1 : 0;
+ !inline_ok) ? 1 : 0;
tx_info->nr_maps = shinfo->nr_frags + tx_info->linear;
data += tx_info->nr_maps - 1;
- if (is_inline(ring->inline_thold, skb, shinfo, &fragptr)) {
- tx_info->inl = 1;
- } else {
+ if (!tx_info->inl) {
dma_addr_t dma = 0;
u32 byte_count = 0;
@@ -827,7 +839,6 @@ netdev_tx_t mlx4_en_xmit(struct sk_buff *skb, struct net_device *dev)
wmb();
data->byte_count = cpu_to_be32(byte_count);
}
- tx_info->inl = 0;
/* tx completion can avoid cache line miss for common cases */
tx_info->map0_dma = dma;
tx_info->map0_byte_count = byte_count;
@@ -899,11 +910,9 @@ netdev_tx_t mlx4_en_xmit(struct sk_buff *skb, struct net_device *dev)
netdev_tx_sent_queue(ring->tx_queue, tx_info->nr_bytes);
AVG_PERF_COUNTER(priv->pstats.tx_pktsz_avg, skb->len);
- if (tx_info->inl) {
+ if (tx_info->inl)
build_inline_wqe(tx_desc, skb, shinfo, real_size, &vlan_tag,
tx_ind, fragptr);
- tx_info->inl = 1;
- }
if (skb->encapsulation) {
struct iphdr *ipv4 = (struct iphdr *)skb_inner_network_header(skb);
--
1.8.3.1
^ permalink raw reply related
* [PATCH net-next V1 10/14] net/mlx4_en: Use local var for skb_headlen(skb)
From: Amir Vadai @ 2014-10-06 6:15 UTC (permalink / raw)
To: David S. Miller, Eric Dumazet
Cc: netdev, Yevgeny Petrilin, Or Gerlitz, Ido Shamay, Amir Vadai
In-Reply-To: <1412576163-7224-1-git-send-email-amirv@mellanox.com>
From: Eric Dumazet <edumazet@google.com>
Access skb_headlen() once in tx flow
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Amir Vadai <amirv@mellanox.com>
---
drivers/net/ethernet/mellanox/mlx4/en_tx.c | 21 +++++++++++----------
1 file changed, 11 insertions(+), 10 deletions(-)
diff --git a/drivers/net/ethernet/mellanox/mlx4/en_tx.c b/drivers/net/ethernet/mellanox/mlx4/en_tx.c
index aa05b09..e00841a 100644
--- a/drivers/net/ethernet/mellanox/mlx4/en_tx.c
+++ b/drivers/net/ethernet/mellanox/mlx4/en_tx.c
@@ -612,6 +612,7 @@ static void build_inline_wqe(struct mlx4_en_tx_desc *tx_desc,
{
struct mlx4_wqe_inline_seg *inl = &tx_desc->inl;
int spc = MLX4_INLINE_ALIGN - CTRL_SIZE - sizeof *inl;
+ unsigned int hlen = skb_headlen(skb);
if (skb->len <= spc) {
if (likely(skb->len >= MIN_PKT_LEN)) {
@@ -621,19 +622,19 @@ static void build_inline_wqe(struct mlx4_en_tx_desc *tx_desc,
memset(((void *)(inl + 1)) + skb->len, 0,
MIN_PKT_LEN - skb->len);
}
- skb_copy_from_linear_data(skb, inl + 1, skb_headlen(skb));
+ skb_copy_from_linear_data(skb, inl + 1, hlen);
if (shinfo->nr_frags)
- memcpy(((void *)(inl + 1)) + skb_headlen(skb), fragptr,
+ memcpy(((void *)(inl + 1)) + hlen, fragptr,
skb_frag_size(&shinfo->frags[0]));
} else {
inl->byte_count = cpu_to_be32(1 << 31 | spc);
- if (skb_headlen(skb) <= spc) {
- skb_copy_from_linear_data(skb, inl + 1, skb_headlen(skb));
- if (skb_headlen(skb) < spc) {
- memcpy(((void *)(inl + 1)) + skb_headlen(skb),
- fragptr, spc - skb_headlen(skb));
- fragptr += spc - skb_headlen(skb);
+ if (hlen <= spc) {
+ skb_copy_from_linear_data(skb, inl + 1, hlen);
+ if (hlen < spc) {
+ memcpy(((void *)(inl + 1)) + hlen,
+ fragptr, spc - hlen);
+ fragptr += spc - hlen;
}
inl = (void *) (inl + 1) + spc;
memcpy(((void *)(inl + 1)), fragptr, skb->len - spc);
@@ -641,9 +642,9 @@ static void build_inline_wqe(struct mlx4_en_tx_desc *tx_desc,
skb_copy_from_linear_data(skb, inl + 1, spc);
inl = (void *) (inl + 1) + spc;
skb_copy_from_linear_data_offset(skb, spc, inl + 1,
- skb_headlen(skb) - spc);
+ hlen - spc);
if (shinfo->nr_frags)
- memcpy(((void *)(inl + 1)) + skb_headlen(skb) - spc,
+ memcpy(((void *)(inl + 1)) + hlen - spc,
fragptr,
skb_frag_size(&shinfo->frags[0]));
}
--
1.8.3.1
^ permalink raw reply related
* [PATCH net-next V1 08/14] net/mlx4_en: mlx4_en_xmit() reads ring->cons once, and ahead of time to avoid stalls
From: Amir Vadai @ 2014-10-06 6:15 UTC (permalink / raw)
To: David S. Miller, Eric Dumazet
Cc: netdev, Yevgeny Petrilin, Or Gerlitz, Ido Shamay, Amir Vadai
In-Reply-To: <1412576163-7224-1-git-send-email-amirv@mellanox.com>
From: Eric Dumazet <edumazet@google.com>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Amir Vadai <amirv@mellanox.com>
---
drivers/net/ethernet/mellanox/mlx4/en_tx.c | 16 +++++++++++-----
1 file changed, 11 insertions(+), 5 deletions(-)
diff --git a/drivers/net/ethernet/mellanox/mlx4/en_tx.c b/drivers/net/ethernet/mellanox/mlx4/en_tx.c
index 63e1f24..4b018ce 100644
--- a/drivers/net/ethernet/mellanox/mlx4/en_tx.c
+++ b/drivers/net/ethernet/mellanox/mlx4/en_tx.c
@@ -691,10 +691,17 @@ netdev_tx_t mlx4_en_xmit(struct sk_buff *skb, struct net_device *dev)
void *fragptr;
bool bounce = false;
bool send_doorbell;
+ u32 ring_cons;
if (!priv->port_up)
goto tx_drop;
+ tx_ind = skb_get_queue_mapping(skb);
+ ring = priv->tx_ring[tx_ind];
+
+ /* fetch ring->cons far ahead before needing it to avoid stall */
+ ring_cons = ACCESS_ONCE(ring->cons);
+
real_size = get_real_size(skb, dev, &lso_header_size);
if (unlikely(!real_size))
goto tx_drop;
@@ -708,13 +715,11 @@ netdev_tx_t mlx4_en_xmit(struct sk_buff *skb, struct net_device *dev)
goto tx_drop;
}
- tx_ind = skb->queue_mapping;
- ring = priv->tx_ring[tx_ind];
if (vlan_tx_tag_present(skb))
vlan_tag = vlan_tx_tag_get(skb);
/* Check available TXBBs And 2K spare for prefetch */
- if (unlikely(((int)(ring->prod - ring->cons)) >
+ if (unlikely(((int)(ring->prod - ring_cons)) >
ring->size - HEADROOM - MAX_DESC_TXBBS)) {
/* every full Tx ring stops queue */
netif_tx_stop_queue(ring->tx_queue);
@@ -728,7 +733,8 @@ netdev_tx_t mlx4_en_xmit(struct sk_buff *skb, struct net_device *dev)
*/
wmb();
- if (unlikely(((int)(ring->prod - ring->cons)) <=
+ ring_cons = ACCESS_ONCE(ring->cons);
+ if (unlikely(((int)(ring->prod - ring_cons)) <=
ring->size - HEADROOM - MAX_DESC_TXBBS)) {
netif_tx_wake_queue(ring->tx_queue);
ring->wake_queue++;
@@ -741,7 +747,7 @@ netdev_tx_t mlx4_en_xmit(struct sk_buff *skb, struct net_device *dev)
/* Track current inflight packets for performance analysis */
AVG_PERF_COUNTER(priv->pstats.inflight_avg,
- (u32) (ring->prod - ring->cons - 1));
+ (u32)(ring->prod - ring_cons - 1));
/* Packet is good - grab an index and transmit it */
index = ring->prod & ring->size_mask;
--
1.8.3.1
^ permalink raw reply related
* [PATCH net-next V1 06/14] net/mlx4_en: Use prefetch in tx path
From: Amir Vadai @ 2014-10-06 6:15 UTC (permalink / raw)
To: David S. Miller, Eric Dumazet
Cc: netdev, Yevgeny Petrilin, Or Gerlitz, Ido Shamay, Amir Vadai
In-Reply-To: <1412576163-7224-1-git-send-email-amirv@mellanox.com>
From: Eric Dumazet <edumazet@google.com>
mlx4_en_free_tx_desc() uses a prefetchw(&skb->users) to speed up
consume_skb()
prefetchw(&ring->tx_queue->dql) to speed up BQL update
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Amir Vadai <amirv@mellanox.com>
---
drivers/net/ethernet/mellanox/mlx4/en_tx.c | 9 +++++++++
1 file changed, 9 insertions(+)
diff --git a/drivers/net/ethernet/mellanox/mlx4/en_tx.c b/drivers/net/ethernet/mellanox/mlx4/en_tx.c
index 772ae6f..9328e6e 100644
--- a/drivers/net/ethernet/mellanox/mlx4/en_tx.c
+++ b/drivers/net/ethernet/mellanox/mlx4/en_tx.c
@@ -37,6 +37,7 @@
#include <linux/mlx4/qp.h>
#include <linux/skbuff.h>
#include <linux/if_vlan.h>
+#include <linux/prefetch.h>
#include <linux/vmalloc.h>
#include <linux/tcp.h>
#include <linux/ip.h>
@@ -267,6 +268,11 @@ static u32 mlx4_en_free_tx_desc(struct mlx4_en_priv *priv,
int nr_maps = tx_info->nr_maps;
int i;
+ /* We do not touch skb here, so prefetch skb->users location
+ * to speedup consume_skb()
+ */
+ prefetchw(&skb->users);
+
if (unlikely(timestamp)) {
struct skb_shared_hwtstamps hwts;
@@ -385,6 +391,7 @@ static bool mlx4_en_process_tx_cq(struct net_device *dev,
if (!priv->port_up)
return true;
+ prefetchw(&ring->tx_queue->dql.limit);
index = cons_index & size_mask;
cqe = mlx4_en_get_cqe(buf, index, priv->cqe_size) + factor;
ring_index = ring->cons & size_mask;
@@ -722,6 +729,8 @@ netdev_tx_t mlx4_en_xmit(struct sk_buff *skb, struct net_device *dev)
}
}
+ prefetchw(&ring->tx_queue->dql);
+
/* Track current inflight packets for performance analysis */
AVG_PERF_COUNTER(priv->pstats.inflight_avg,
(u32) (ring->prod - ring->cons - 1));
--
1.8.3.1
^ permalink raw reply related
* [PATCH net-next V1 14/14] net/mlx4_en: Use the new tx_copybreak to set inline threshold
From: Amir Vadai @ 2014-10-06 6:16 UTC (permalink / raw)
To: David S. Miller, Eric Dumazet
Cc: netdev, Yevgeny Petrilin, Or Gerlitz, Ido Shamay, Amir Vadai
In-Reply-To: <1412576163-7224-1-git-send-email-amirv@mellanox.com>
From: Eric Dumazet <edumazet@google.com>
Instead of setting inline threshold using module parameter only on
driver load, use set_tunable() to set it dynamically.
No need to store the threshold per ring, using instead the netdev global
priv->prof->inline_thold
Initial value still is set using the module parameter, therefore
backward compatability is kept.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Amir Vadai <amirv@mellanox.com>
---
drivers/net/ethernet/mellanox/mlx4/en_ethtool.c | 44 +++++++++++++++++++++++++
drivers/net/ethernet/mellanox/mlx4/en_tx.c | 1 -
drivers/net/ethernet/mellanox/mlx4/mlx4_en.h | 1 -
3 files changed, 44 insertions(+), 2 deletions(-)
diff --git a/drivers/net/ethernet/mellanox/mlx4/en_ethtool.c b/drivers/net/ethernet/mellanox/mlx4/en_ethtool.c
index 42c9f8b..b2d9e1f 100644
--- a/drivers/net/ethernet/mellanox/mlx4/en_ethtool.c
+++ b/drivers/net/ethernet/mellanox/mlx4/en_ethtool.c
@@ -1267,6 +1267,48 @@ static u32 mlx4_en_get_priv_flags(struct net_device *dev)
return priv->pflags;
}
+static int mlx4_en_get_tunable(struct net_device *dev,
+ const struct ethtool_tunable *tuna,
+ void *data)
+{
+ const struct mlx4_en_priv *priv = netdev_priv(dev);
+ int ret = 0;
+
+ switch (tuna->id) {
+ case ETHTOOL_TX_COPYBREAK:
+ *(u32 *)data = priv->prof->inline_thold;
+ break;
+ default:
+ ret = -EINVAL;
+ break;
+ }
+
+ return ret;
+}
+
+static int mlx4_en_set_tunable(struct net_device *dev,
+ const struct ethtool_tunable *tuna,
+ const void *data)
+{
+ struct mlx4_en_priv *priv = netdev_priv(dev);
+ int val, ret = 0;
+
+ switch (tuna->id) {
+ case ETHTOOL_TX_COPYBREAK:
+ val = *(u32 *)data;
+ if (val < MIN_PKT_LEN || val > MAX_INLINE)
+ ret = -EINVAL;
+ else
+ priv->prof->inline_thold = val;
+ break;
+ default:
+ ret = -EINVAL;
+ break;
+ }
+
+ return ret;
+}
+
const struct ethtool_ops mlx4_en_ethtool_ops = {
.get_drvinfo = mlx4_en_get_drvinfo,
@@ -1297,6 +1339,8 @@ const struct ethtool_ops mlx4_en_ethtool_ops = {
.get_ts_info = mlx4_en_get_ts_info,
.set_priv_flags = mlx4_en_set_priv_flags,
.get_priv_flags = mlx4_en_get_priv_flags,
+ .get_tunable = mlx4_en_get_tunable,
+ .set_tunable = mlx4_en_set_tunable,
};
diff --git a/drivers/net/ethernet/mellanox/mlx4/en_tx.c b/drivers/net/ethernet/mellanox/mlx4/en_tx.c
index f0080c5..92a7cf4 100644
--- a/drivers/net/ethernet/mellanox/mlx4/en_tx.c
+++ b/drivers/net/ethernet/mellanox/mlx4/en_tx.c
@@ -66,7 +66,6 @@ int mlx4_en_create_tx_ring(struct mlx4_en_priv *priv,
ring->size = size;
ring->size_mask = size - 1;
ring->stride = stride;
- ring->inline_thold = priv->prof->inline_thold;
tmp = size * sizeof(struct mlx4_en_tx_info);
ring->tx_info = kmalloc_node(tmp, GFP_KERNEL | __GFP_NOWARN, node);
diff --git a/drivers/net/ethernet/mellanox/mlx4/mlx4_en.h b/drivers/net/ethernet/mellanox/mlx4/mlx4_en.h
index a904030..8fef658 100644
--- a/drivers/net/ethernet/mellanox/mlx4/mlx4_en.h
+++ b/drivers/net/ethernet/mellanox/mlx4/mlx4_en.h
@@ -295,7 +295,6 @@ struct mlx4_en_tx_ring {
bool bf_alloced;
struct netdev_queue *tx_queue;
int hwtstamp_tx_type;
- int inline_thold;
} ____cacheline_aligned_in_smp;
struct mlx4_en_rx_desc {
--
1.8.3.1
^ permalink raw reply related
* [PATCH net-next V1 03/14] net/mlx4_en: Avoid calling bswap in tx fast path
From: Amir Vadai @ 2014-10-06 6:15 UTC (permalink / raw)
To: David S. Miller, Eric Dumazet
Cc: netdev, Yevgeny Petrilin, Or Gerlitz, Ido Shamay, Amir Vadai
In-Reply-To: <1412576163-7224-1-git-send-email-amirv@mellanox.com>
From: Eric Dumazet <edumazet@google.com>
- doorbell_qpn is stored in the cpu_to_be32() way to avoid bswap() in fast
path.
- mdev->mr.key stored in ring->mr_key to also avoid bswap() and access to
cold cache line.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Amir Vadai <amirv@mellanox.com>
---
drivers/net/ethernet/mellanox/mlx4/en_tx.c | 17 ++++++++++-------
drivers/net/ethernet/mellanox/mlx4/mlx4_en.h | 3 ++-
2 files changed, 12 insertions(+), 8 deletions(-)
diff --git a/drivers/net/ethernet/mellanox/mlx4/en_tx.c b/drivers/net/ethernet/mellanox/mlx4/en_tx.c
index d2f06a7..3ea17f9 100644
--- a/drivers/net/ethernet/mellanox/mlx4/en_tx.c
+++ b/drivers/net/ethernet/mellanox/mlx4/en_tx.c
@@ -195,7 +195,8 @@ int mlx4_en_activate_tx_ring(struct mlx4_en_priv *priv,
memset(ring->buf, 0, ring->buf_size);
ring->qp_state = MLX4_QP_STATE_RST;
- ring->doorbell_qpn = ring->qp.qpn << 8;
+ ring->doorbell_qpn = cpu_to_be32(ring->qp.qpn << 8);
+ ring->mr_key = cpu_to_be32(mdev->mr.key);
mlx4_en_fill_qp_context(priv, ring->size, ring->stride, 1, 0, ring->qpn,
ring->cqn, user_prio, &ring->context);
@@ -654,7 +655,6 @@ static void mlx4_bf_copy(void __iomem *dst, const void *src,
netdev_tx_t mlx4_en_xmit(struct sk_buff *skb, struct net_device *dev)
{
struct mlx4_en_priv *priv = netdev_priv(dev);
- struct mlx4_en_dev *mdev = priv->mdev;
struct device *ddev = priv->ddev;
struct mlx4_en_tx_ring *ring;
struct mlx4_en_tx_desc *tx_desc;
@@ -769,7 +769,7 @@ netdev_tx_t mlx4_en_xmit(struct sk_buff *skb, struct net_device *dev)
goto tx_drop_unmap;
data->addr = cpu_to_be64(dma);
- data->lkey = cpu_to_be32(mdev->mr.key);
+ data->lkey = ring->mr_key;
wmb();
data->byte_count = cpu_to_be32(skb_frag_size(frag));
--data;
@@ -787,7 +787,7 @@ netdev_tx_t mlx4_en_xmit(struct sk_buff *skb, struct net_device *dev)
goto tx_drop_unmap;
data->addr = cpu_to_be64(dma);
- data->lkey = cpu_to_be32(mdev->mr.key);
+ data->lkey = ring->mr_key;
wmb();
data->byte_count = cpu_to_be32(byte_count);
}
@@ -879,9 +879,12 @@ netdev_tx_t mlx4_en_xmit(struct sk_buff *skb, struct net_device *dev)
send_doorbell = !skb->xmit_more || netif_xmit_stopped(ring->tx_queue);
+ real_size = (real_size / 16) & 0x3f;
+
if (ring->bf_enabled && desc_size <= MAX_BF && !bounce &&
!vlan_tx_tag_present(skb) && send_doorbell) {
- tx_desc->ctrl.bf_qpn |= cpu_to_be32(ring->doorbell_qpn);
+ tx_desc->ctrl.bf_qpn = ring->doorbell_qpn |
+ cpu_to_be32(real_size);
op_own |= htonl((bf_index & 0xffff) << 8);
/* Ensure new descriptor hits memory
@@ -911,8 +914,8 @@ netdev_tx_t mlx4_en_xmit(struct sk_buff *skb, struct net_device *dev)
tx_desc->ctrl.owner_opcode = op_own;
if (send_doorbell) {
wmb();
- iowrite32be(ring->doorbell_qpn,
- ring->bf.uar->map + MLX4_SEND_DOORBELL);
+ iowrite32(ring->doorbell_qpn,
+ ring->bf.uar->map + MLX4_SEND_DOORBELL);
} else {
ring->xmit_more++;
}
diff --git a/drivers/net/ethernet/mellanox/mlx4/mlx4_en.h b/drivers/net/ethernet/mellanox/mlx4/mlx4_en.h
index b7bde95..ab34461 100644
--- a/drivers/net/ethernet/mellanox/mlx4/mlx4_en.h
+++ b/drivers/net/ethernet/mellanox/mlx4/mlx4_en.h
@@ -279,7 +279,8 @@ struct mlx4_en_tx_ring {
u16 stride;
u16 cqn; /* index of port CQ associated with this ring */
u32 buf_size;
- u32 doorbell_qpn;
+ __be32 doorbell_qpn;
+ __be32 mr_key;
void *buf;
struct mlx4_en_tx_info *tx_info;
u8 *bounce_buf;
--
1.8.3.1
^ permalink raw reply related
* [PATCH net-next V1 05/14] net/mlx4_en: Avoid a cache line miss in TX completion for single frag skb's
From: Amir Vadai @ 2014-10-06 6:15 UTC (permalink / raw)
To: David S. Miller, Eric Dumazet
Cc: netdev, Yevgeny Petrilin, Or Gerlitz, Ido Shamay, Amir Vadai
In-Reply-To: <1412576163-7224-1-git-send-email-amirv@mellanox.com>
From: Eric Dumazet <edumazet@google.com>
Add frag0_dma/frag0_byte_count into mlx4_en_tx_info to avoid a cache
line miss in TX completion for frames having one dma element. (We avoid
reading back the tx descriptor)
Note this could be extended to 2/3 dma elements later, as we have free
room in mlx4_en_tx_info
Also, mlx4_en_free_tx_desc() no longer accesses skb_shinfo(). We use a
new nr_maps fields in mlx4_en_tx_info to avoid 2 or 3 cache misses.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Amir Vadai <amirv@mellanox.com>
---
drivers/net/ethernet/mellanox/mlx4/en_tx.c | 83 +++++++++++++++-------------
drivers/net/ethernet/mellanox/mlx4/mlx4_en.h | 3 +
2 files changed, 49 insertions(+), 37 deletions(-)
diff --git a/drivers/net/ethernet/mellanox/mlx4/en_tx.c b/drivers/net/ethernet/mellanox/mlx4/en_tx.c
index 02ade59..772ae6f 100644
--- a/drivers/net/ethernet/mellanox/mlx4/en_tx.c
+++ b/drivers/net/ethernet/mellanox/mlx4/en_tx.c
@@ -259,38 +259,40 @@ static u32 mlx4_en_free_tx_desc(struct mlx4_en_priv *priv,
struct mlx4_en_tx_ring *ring,
int index, u8 owner, u64 timestamp)
{
- struct mlx4_en_dev *mdev = priv->mdev;
struct mlx4_en_tx_info *tx_info = &ring->tx_info[index];
struct mlx4_en_tx_desc *tx_desc = ring->buf + index * TXBB_SIZE;
struct mlx4_wqe_data_seg *data = (void *) tx_desc + tx_info->data_offset;
- struct sk_buff *skb = tx_info->skb;
- struct skb_frag_struct *frag;
void *end = ring->buf + ring->buf_size;
- int frags = skb_shinfo(skb)->nr_frags;
+ struct sk_buff *skb = tx_info->skb;
+ int nr_maps = tx_info->nr_maps;
int i;
- struct skb_shared_hwtstamps hwts;
- if (timestamp) {
- mlx4_en_fill_hwtstamps(mdev, &hwts, timestamp);
+ if (unlikely(timestamp)) {
+ struct skb_shared_hwtstamps hwts;
+
+ mlx4_en_fill_hwtstamps(priv->mdev, &hwts, timestamp);
skb_tstamp_tx(skb, &hwts);
}
/* Optimize the common case when there are no wraparounds */
if (likely((void *) tx_desc + tx_info->nr_txbb * TXBB_SIZE <= end)) {
if (!tx_info->inl) {
- if (tx_info->linear) {
+ if (tx_info->linear)
dma_unmap_single(priv->ddev,
- (dma_addr_t) be64_to_cpu(data->addr),
- be32_to_cpu(data->byte_count),
- PCI_DMA_TODEVICE);
- ++data;
- }
-
- for (i = 0; i < frags; i++) {
- frag = &skb_shinfo(skb)->frags[i];
+ tx_info->map0_dma,
+ tx_info->map0_byte_count,
+ PCI_DMA_TODEVICE);
+ else
+ dma_unmap_page(priv->ddev,
+ tx_info->map0_dma,
+ tx_info->map0_byte_count,
+ PCI_DMA_TODEVICE);
+ for (i = 1; i < nr_maps; i++) {
+ data++;
dma_unmap_page(priv->ddev,
- (dma_addr_t) be64_to_cpu(data[i].addr),
- skb_frag_size(frag), PCI_DMA_TODEVICE);
+ (dma_addr_t)be64_to_cpu(data->addr),
+ be32_to_cpu(data->byte_count),
+ PCI_DMA_TODEVICE);
}
}
} else {
@@ -299,23 +301,25 @@ static u32 mlx4_en_free_tx_desc(struct mlx4_en_priv *priv,
data = ring->buf + ((void *)data - end);
}
- if (tx_info->linear) {
+ if (tx_info->linear)
dma_unmap_single(priv->ddev,
- (dma_addr_t) be64_to_cpu(data->addr),
- be32_to_cpu(data->byte_count),
- PCI_DMA_TODEVICE);
- ++data;
- }
-
- for (i = 0; i < frags; i++) {
+ tx_info->map0_dma,
+ tx_info->map0_byte_count,
+ PCI_DMA_TODEVICE);
+ else
+ dma_unmap_page(priv->ddev,
+ tx_info->map0_dma,
+ tx_info->map0_byte_count,
+ PCI_DMA_TODEVICE);
+ for (i = 1; i < nr_maps; i++) {
+ data++;
/* Check for wraparound before unmapping */
if ((void *) data >= end)
data = ring->buf;
- frag = &skb_shinfo(skb)->frags[i];
dma_unmap_page(priv->ddev,
- (dma_addr_t) be64_to_cpu(data->addr),
- skb_frag_size(frag), PCI_DMA_TODEVICE);
- ++data;
+ (dma_addr_t)be64_to_cpu(data->addr),
+ be32_to_cpu(data->byte_count),
+ PCI_DMA_TODEVICE);
}
}
}
@@ -751,19 +755,22 @@ netdev_tx_t mlx4_en_xmit(struct sk_buff *skb, struct net_device *dev)
tx_info->linear = (lso_header_size < skb_headlen(skb) &&
!is_inline(ring->inline_thold, skb, NULL)) ? 1 : 0;
- data += skb_shinfo(skb)->nr_frags + tx_info->linear - 1;
+ tx_info->nr_maps = skb_shinfo(skb)->nr_frags + tx_info->linear;
+ data += tx_info->nr_maps - 1;
if (is_inline(ring->inline_thold, skb, &fragptr)) {
tx_info->inl = 1;
} else {
+ dma_addr_t dma = 0;
+ u32 byte_count = 0;
+
/* Map fragments if any */
for (i = skb_shinfo(skb)->nr_frags - 1; i >= 0; i--) {
const struct skb_frag_struct *frag;
- dma_addr_t dma;
-
frag = &skb_shinfo(skb)->frags[i];
+ byte_count = skb_frag_size(frag);
dma = skb_frag_dma_map(ddev, frag,
- 0, skb_frag_size(frag),
+ 0, byte_count,
DMA_TO_DEVICE);
if (dma_mapping_error(ddev, dma))
goto tx_drop_unmap;
@@ -771,14 +778,13 @@ netdev_tx_t mlx4_en_xmit(struct sk_buff *skb, struct net_device *dev)
data->addr = cpu_to_be64(dma);
data->lkey = ring->mr_key;
wmb();
- data->byte_count = cpu_to_be32(skb_frag_size(frag));
+ data->byte_count = cpu_to_be32(byte_count);
--data;
}
/* Map linear part if needed */
if (tx_info->linear) {
- u32 byte_count = skb_headlen(skb) - lso_header_size;
- dma_addr_t dma;
+ byte_count = skb_headlen(skb) - lso_header_size;
dma = dma_map_single(ddev, skb->data +
lso_header_size, byte_count,
@@ -792,6 +798,9 @@ netdev_tx_t mlx4_en_xmit(struct sk_buff *skb, struct net_device *dev)
data->byte_count = cpu_to_be32(byte_count);
}
tx_info->inl = 0;
+ /* tx completion can avoid cache line miss for common cases */
+ tx_info->map0_dma = dma;
+ tx_info->map0_byte_count = byte_count;
}
/*
diff --git a/drivers/net/ethernet/mellanox/mlx4/mlx4_en.h b/drivers/net/ethernet/mellanox/mlx4/mlx4_en.h
index ab34461..a904030 100644
--- a/drivers/net/ethernet/mellanox/mlx4/mlx4_en.h
+++ b/drivers/net/ethernet/mellanox/mlx4/mlx4_en.h
@@ -216,12 +216,15 @@ enum cq_type {
struct mlx4_en_tx_info {
struct sk_buff *skb;
+ dma_addr_t map0_dma;
+ u32 map0_byte_count;
u32 nr_txbb;
u32 nr_bytes;
u8 linear;
u8 data_offset;
u8 inl;
u8 ts_requested;
+ u8 nr_maps;
} ____cacheline_aligned_in_smp;
--
1.8.3.1
^ permalink raw reply related
* [PATCH net-next V1 00/14] net/mlx4_en: Optimizations to TX flow
From: Amir Vadai @ 2014-10-06 6:15 UTC (permalink / raw)
To: David S. Miller, Eric Dumazet
Cc: netdev, Yevgeny Petrilin, Or Gerlitz, Ido Shamay, Amir Vadai
Hi,
This patchset contains optimizations to TX flow in mlx4_en driver. It also introduce
setting/getting tx copybreak, to enable controlling inline threshold dynamically.
TX flow optimizations was authored and posted to the mailing list by Eric
Dumazet [1] as a single patch. I splitted this patch to smaller patches,
Reviewed it and tested.
Changed from original patch:
- s/iowrite32be/iowrite32/, since ring->doorbell_qpn is stored as be32
The tx copybreak patch was also suggested by Eric Dumazet, and was edited and
reviewed by me. User space patch will be sent after kernel code is ready.
I am sending this patchset now since the merge window is near and don't want to
miss it.
More work need to do:
- Disable BF when xmit_more is in use
- Make TSO use xmit_more too. Maybe by splitting small TSO packets in the
driver itself, to avoid extra cpu/memory costs of GSO before the driver
- Fix mlx4_en_xmit buggy handling of queue full in the middle of a burst
partially posted to send queue using xmit_more
Eric, I edited the patches to have you as the Author and the first
signed-off-by. I hope it is ok with you (I wasn't sure if it is ok to sign by
you), anyway all the credit to those changes should go to you.
Patchset was tested and applied over commit 1e203c1 "(net: sched:
suspicious RCU usage in qdisc_watchdog")
[1] - https://patchwork.ozlabs.org/patch/394256/
Changes from V0:
- Patch 14/14 ("Use the new tx_copybreak to set inline threshold"):
- Use same coding convention as currently is in en_ethtool.c
- Patch 1/14 ("Code cleanups in tx path") and Patch 9/14 ("Use local var in
tx flow for skb_shinfo(skb)"):
- local var shinfo was used by mistake in Patch 1/14 while declared at 9/14.
Fixed it for the sake of future bisections
Thanks,
Amir
Eric Dumazet (14):
net/mlx4_en: Code cleanups in tx path
net/mlx4_en: Align tx path structures to cache lines
net/mlx4_en: Avoid calling bswap in tx fast path
net/mlx4_en: tx_info allocated with kmalloc() instead of vmalloc()
net/mlx4_en: Avoid a cache line miss in TX completion for single frag
skb's
net/mlx4_en: Use prefetch in tx path
net/mlx4_en: Avoid false sharing in mlx4_en_en_process_tx_cq()
net/mlx4_en: mlx4_en_xmit() reads ring->cons once, and ahead of time
to avoid stalls
net/mlx4_en: Use local var in tx flow for skb_shinfo(skb)
net/mlx4_en: Use local var for skb_headlen(skb)
net/mlx4_en: tx_info->ts_requested was not cleared
net/mlx4_en: Enable the compiler to make is_inline() inlined
ethtool: Ethtool parameter to dynamically change tx_copybreak
net/mlx4_en: Use the new tx_copybreak to set inline threshold
drivers/net/ethernet/mellanox/mlx4/en_ethtool.c | 44 ++++
drivers/net/ethernet/mellanox/mlx4/en_tx.c | 330 ++++++++++++++----------
drivers/net/ethernet/mellanox/mlx4/mlx4_en.h | 90 ++++---
include/linux/mlx4/device.h | 2 +-
include/uapi/linux/ethtool.h | 1 +
net/core/ethtool.c | 1 +
6 files changed, 290 insertions(+), 178 deletions(-)
--
1.8.3.1
^ permalink raw reply
* [PATCH net-next V1 01/14] net/mlx4_en: Code cleanups in tx path
From: Amir Vadai @ 2014-10-06 6:15 UTC (permalink / raw)
To: David S. Miller, Eric Dumazet
Cc: netdev, Yevgeny Petrilin, Or Gerlitz, Ido Shamay, Amir Vadai
In-Reply-To: <1412576163-7224-1-git-send-email-amirv@mellanox.com>
From: Eric Dumazet <edumazet@google.com>
- Remove unused variable ring->poll_cnt
- No need to set some fields if using blueflame
- Add missing const's
- Use unlikely
- Remove unneeded new line
- Make some comments more precise
- struct mlx4_bf @offset field reduced to unsigned int to save space
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Amir Vadai <amirv@mellanox.com>
---
drivers/net/ethernet/mellanox/mlx4/en_tx.c | 47 +++++++++++++++-------------
drivers/net/ethernet/mellanox/mlx4/mlx4_en.h | 1 -
include/linux/mlx4/device.h | 2 +-
3 files changed, 26 insertions(+), 24 deletions(-)
diff --git a/drivers/net/ethernet/mellanox/mlx4/en_tx.c b/drivers/net/ethernet/mellanox/mlx4/en_tx.c
index 0c50125..d2f06a7 100644
--- a/drivers/net/ethernet/mellanox/mlx4/en_tx.c
+++ b/drivers/net/ethernet/mellanox/mlx4/en_tx.c
@@ -191,7 +191,6 @@ int mlx4_en_activate_tx_ring(struct mlx4_en_priv *priv,
ring->prod = 0;
ring->cons = 0xffffffff;
ring->last_nr_txbb = 1;
- ring->poll_cnt = 0;
memset(ring->tx_info, 0, ring->size * sizeof(struct mlx4_en_tx_info));
memset(ring->buf, 0, ring->buf_size);
@@ -512,7 +511,8 @@ static struct mlx4_en_tx_desc *mlx4_en_bounce_to_desc(struct mlx4_en_priv *priv,
return ring->buf + index * TXBB_SIZE;
}
-static int is_inline(int inline_thold, struct sk_buff *skb, void **pfrag)
+static bool is_inline(int inline_thold, const struct sk_buff *skb,
+ void **pfrag)
{
void *ptr;
@@ -535,7 +535,7 @@ static int is_inline(int inline_thold, struct sk_buff *skb, void **pfrag)
return 0;
}
-static int inline_size(struct sk_buff *skb)
+static int inline_size(const struct sk_buff *skb)
{
if (skb->len + CTRL_SIZE + sizeof(struct mlx4_wqe_inline_seg)
<= MLX4_INLINE_ALIGN)
@@ -546,7 +546,8 @@ static int inline_size(struct sk_buff *skb)
sizeof(struct mlx4_wqe_inline_seg), 16);
}
-static int get_real_size(struct sk_buff *skb, struct net_device *dev,
+static int get_real_size(const struct sk_buff *skb,
+ struct net_device *dev,
int *lso_header_size)
{
struct mlx4_en_priv *priv = netdev_priv(dev);
@@ -581,8 +582,10 @@ static int get_real_size(struct sk_buff *skb, struct net_device *dev,
return real_size;
}
-static void build_inline_wqe(struct mlx4_en_tx_desc *tx_desc, struct sk_buff *skb,
- int real_size, u16 *vlan_tag, int tx_ind, void *fragptr)
+static void build_inline_wqe(struct mlx4_en_tx_desc *tx_desc,
+ const struct sk_buff *skb,
+ int real_size, u16 *vlan_tag,
+ int tx_ind, void *fragptr)
{
struct mlx4_wqe_inline_seg *inl = &tx_desc->inl;
int spc = MLX4_INLINE_ALIGN - CTRL_SIZE - sizeof *inl;
@@ -642,7 +645,8 @@ u16 mlx4_en_select_queue(struct net_device *dev, struct sk_buff *skb,
return fallback(dev, skb) % rings_p_up + up * rings_p_up;
}
-static void mlx4_bf_copy(void __iomem *dst, unsigned long *src, unsigned bytecnt)
+static void mlx4_bf_copy(void __iomem *dst, const void *src,
+ unsigned int bytecnt)
{
__iowrite64_copy(dst, src, bytecnt / 8);
}
@@ -736,11 +740,10 @@ netdev_tx_t mlx4_en_xmit(struct sk_buff *skb, struct net_device *dev)
tx_info->skb = skb;
tx_info->nr_txbb = nr_txbb;
+ data = &tx_desc->data;
if (lso_header_size)
data = ((void *)&tx_desc->lso + ALIGN(lso_header_size + 4,
DS_SIZE));
- else
- data = &tx_desc->data;
/* valid only for none inline segments */
tx_info->data_offset = (void *)data - (void *)tx_desc;
@@ -753,9 +756,9 @@ netdev_tx_t mlx4_en_xmit(struct sk_buff *skb, struct net_device *dev)
if (is_inline(ring->inline_thold, skb, &fragptr)) {
tx_info->inl = 1;
} else {
- /* Map fragments */
+ /* Map fragments if any */
for (i = skb_shinfo(skb)->nr_frags - 1; i >= 0; i--) {
- struct skb_frag_struct *frag;
+ const struct skb_frag_struct *frag;
dma_addr_t dma;
frag = &skb_shinfo(skb)->frags[i];
@@ -772,7 +775,7 @@ netdev_tx_t mlx4_en_xmit(struct sk_buff *skb, struct net_device *dev)
--data;
}
- /* Map linear part */
+ /* Map linear part if needed */
if (tx_info->linear) {
u32 byte_count = skb_headlen(skb) - lso_header_size;
dma_addr_t dma;
@@ -795,18 +798,14 @@ netdev_tx_t mlx4_en_xmit(struct sk_buff *skb, struct net_device *dev)
* For timestamping add flag to skb_shinfo and
* set flag for further reference
*/
- if (ring->hwtstamp_tx_type == HWTSTAMP_TX_ON &&
- skb_shinfo(skb)->tx_flags & SKBTX_HW_TSTAMP) {
+ if (unlikely(ring->hwtstamp_tx_type == HWTSTAMP_TX_ON &&
+ skb_shinfo(skb)->tx_flags & SKBTX_HW_TSTAMP)) {
skb_shinfo(skb)->tx_flags |= SKBTX_IN_PROGRESS;
tx_info->ts_requested = 1;
}
/* Prepare ctrl segement apart opcode+ownership, which depends on
* whether LSO is used */
- tx_desc->ctrl.vlan_tag = cpu_to_be16(vlan_tag);
- tx_desc->ctrl.ins_vlan = MLX4_WQE_CTRL_INS_VLAN *
- !!vlan_tx_tag_present(skb);
- tx_desc->ctrl.fence_size = (real_size / 16) & 0x3f;
tx_desc->ctrl.srcrb_flags = priv->ctrl_flags;
if (likely(skb->ip_summed == CHECKSUM_PARTIAL)) {
tx_desc->ctrl.srcrb_flags |= cpu_to_be32(MLX4_WQE_CTRL_IP_CSUM |
@@ -852,7 +851,6 @@ netdev_tx_t mlx4_en_xmit(struct sk_buff *skb, struct net_device *dev)
cpu_to_be32(MLX4_EN_BIT_DESC_OWN) : 0);
tx_info->nr_bytes = max_t(unsigned int, skb->len, ETH_ZLEN);
ring->packets++;
-
}
ring->bytes += tx_info->nr_bytes;
netdev_tx_sent_queue(ring->tx_queue, tx_info->nr_bytes);
@@ -874,7 +872,7 @@ netdev_tx_t mlx4_en_xmit(struct sk_buff *skb, struct net_device *dev)
ring->prod += nr_txbb;
/* If we used a bounce buffer then copy descriptor back into place */
- if (bounce)
+ if (unlikely(bounce))
tx_desc = mlx4_en_bounce_to_desc(priv, ring, index, desc_size);
skb_tx_timestamp(skb);
@@ -894,13 +892,18 @@ netdev_tx_t mlx4_en_xmit(struct sk_buff *skb, struct net_device *dev)
wmb();
- mlx4_bf_copy(ring->bf.reg + ring->bf.offset, (unsigned long *) &tx_desc->ctrl,
- desc_size);
+ mlx4_bf_copy(ring->bf.reg + ring->bf.offset, &tx_desc->ctrl,
+ desc_size);
wmb();
ring->bf.offset ^= ring->bf.buf_size;
} else {
+ tx_desc->ctrl.vlan_tag = cpu_to_be16(vlan_tag);
+ tx_desc->ctrl.ins_vlan = MLX4_WQE_CTRL_INS_VLAN *
+ !!vlan_tx_tag_present(skb);
+ tx_desc->ctrl.fence_size = real_size;
+
/* Ensure new descriptor hits memory
* before setting ownership of this descriptor to HW
*/
diff --git a/drivers/net/ethernet/mellanox/mlx4/mlx4_en.h b/drivers/net/ethernet/mellanox/mlx4/mlx4_en.h
index 84c9d5d..e54b653 100644
--- a/drivers/net/ethernet/mellanox/mlx4/mlx4_en.h
+++ b/drivers/net/ethernet/mellanox/mlx4/mlx4_en.h
@@ -263,7 +263,6 @@ struct mlx4_en_tx_ring {
u32 buf_size;
u32 doorbell_qpn;
void *buf;
- u16 poll_cnt;
struct mlx4_en_tx_info *tx_info;
u8 *bounce_buf;
u8 queue_index;
diff --git a/include/linux/mlx4/device.h b/include/linux/mlx4/device.h
index b2f8ab9..37e4404 100644
--- a/include/linux/mlx4/device.h
+++ b/include/linux/mlx4/device.h
@@ -583,7 +583,7 @@ struct mlx4_uar {
};
struct mlx4_bf {
- unsigned long offset;
+ unsigned int offset;
int buf_size;
struct mlx4_uar *uar;
void __iomem *reg;
--
1.8.3.1
^ permalink raw reply related
* Re: [PATCH net-next 00/14] net/mlx4_en: Optimizations to TX flow
From: David Miller @ 2014-10-06 5:04 UTC (permalink / raw)
To: amirv; +Cc: edumazet, netdev, yevgenyp, ogerlitz, idos
In-Reply-To: <1412501722-25092-1-git-send-email-amirv@mellanox.com>
From: Amir Vadai <amirv@mellanox.com>
Date: Sun, 5 Oct 2014 12:35:08 +0300
> This patchset contains optimizations to TX flow in mlx4_en driver. It also introduce
> setting/getting tx copybreak, to enable controlling inline threshold dynamically.
>
> TX flow optimizations was authored and posted to the mailing list by Eric
> Dumazet [1] as a single patch. I splitted this patch to smaller patches,
> Reviewed it and tested.
> Changed from original patch:
> - s/iowrite32be/iowrite32/, since ring->doorbell_qpn is stored as be32
>
> The tx copybreak patch was also suggested by Eric Dumazet, and was edited and
> reviewed by me. User space patch will be sent after kernel code is ready.
>
> I am sending this patchset now since the merge window is near and don't want to
> miss it.
>
> More work need to do:
> - Disable BF when xmit_more is in use
> - Make TSO use xmit_more too. Maybe by splitting small TSO packets in the
> driver itself, to avoid extra cpu/memory costs of GSO before the driver
> - Fix mlx4_en_xmit buggy handling of queue full in the middle of a burst
> partially posted to send queue using xmit_more
>
> Eric, I edited the patches to have you as the Author and the first
> signed-off-by. I hope it is ok with you (I wasn't sure if it is ok to sign by
> you), anyway all the credit to those changes should go to you.
>
> Patchset was tested and applied over commit 1e203c1 "(net: sched:
> suspicious RCU usage in qdisc_watchdog")
>
> [1] - https://patchwork.ozlabs.org/patch/394256/
Looks great, nice work everyone.
^ permalink raw reply
* Re: [PATCH v8 net-next 1/2] bonding: display xmit_hash_policy for non-dynamic-tlb mode
From: David Miller @ 2014-10-06 4:58 UTC (permalink / raw)
To: maheshb; +Cc: j.vosburgh, andy, vfalico, nikolay, netdev, edumazet, maze
In-Reply-To: <1412469884-27308-1-git-send-email-maheshb@google.com>
After 8 revisions, I want to see some ACKs before applying these
two changes :)
^ permalink raw reply
* Re: [PATCH net-next] net: sched: avoid costly atomic operation in fq_dequeue()
From: David Miller @ 2014-10-06 4:55 UTC (permalink / raw)
To: eric.dumazet; +Cc: netdev
In-Reply-To: <1412442691.17245.40.camel@edumazet-glaptop2.roam.corp.google.com>
From: Eric Dumazet <eric.dumazet@gmail.com>
Date: Sat, 04 Oct 2014 10:11:31 -0700
> From: Eric Dumazet <edumazet@google.com>
>
> Standard qdisc API to setup a timer implies an atomic operation on every
> packet dequeue : qdisc_unthrottled()
>
> It turns out this is not really needed for FQ, as FQ has no concept of
> global qdisc throttling, being a qdisc handling many different flows,
> some of them can be throttled, while others are not.
>
> Fix is straightforward : add a 'bool throttle' to
> qdisc_watchdog_schedule_ns(), and remove calls to qdisc_unthrottled()
> in sch_fq.
>
> Signed-off-by: Eric Dumazet <edumazet@google.com>
Applied, thanks Eric.
^ permalink raw reply
* Re: [PATCH net-next] fec: Fix fec_enet_alloc_buffers() error path
From: David Miller @ 2014-10-06 4:54 UTC (permalink / raw)
To: festevam; +Cc: rmk+kernel, Frank.Li, netdev, fabio.estevam
In-Reply-To: <1412440801-15381-1-git-send-email-festevam@gmail.com>
From: Fabio Estevam <festevam@gmail.com>
Date: Sat, 4 Oct 2014 13:40:01 -0300
> From: Fabio Estevam <fabio.estevam@freescale.com>
>
> When fec_enet_alloc_buffers() fails we should better undo the previous actions,
> which consists of: disabling the FEC clocks and putting the FEC pins into
> inactive state.
>
> The error path for fec_enet_mii_probe() is kept unchanged.
>
> Signed-off-by: Fabio Estevam <fabio.estevam@freescale.com>
Applied, thanks Fabio.
^ permalink raw reply
* Re: bridge: Do not compile options in br_parse_ip_options
From: David Miller @ 2014-10-06 4:53 UTC (permalink / raw)
To: herbert; +Cc: fw, netfilter-devel, bsd, stephen, netdev, eric.dumazet, davidn
In-Reply-To: <20141004141802.GA10878@gondor.apana.org.au>
From: Herbert Xu <herbert@gondor.apana.org.au>
Date: Sat, 4 Oct 2014 22:18:02 +0800
> bridge: Do not compile options in br_parse_ip_options
>
> Commit 462fb2af9788a82a534f8184abfde31574e1cfa0
>
> bridge : Sanitize skb before it enters the IP stack
>
> broke when IP options are actually used because it mangles the
> skb as if it entered the IP stack which is wrong because the
> bridge is supposed to operate below the IP stack.
>
> Since nobody has actually requested for parsing of IP options
> this patch fixes it by simply reverting to the previous approach
> of ignoring all IP options, i.e., zeroing the IPCB.
>
> If and when somebody who uses IP options and actually needs them
> to be parsed by the bridge complains then we can revisit this.
>
> Reported-by: David Newall <davidn@davidnewall.com>
> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Agreed that mangling the packet is definitely wrong here, and since
you preserve the CB clearing this change should be fine.
Please submit this formally after it's been tested.
Thanks.
^ permalink raw reply
* Re: [PATCH] drivers/net/phy/Kconfig: Let MDIO_BCM_UNIMAC depend on HAS_IOMEM
From: David Miller @ 2014-10-06 4:46 UTC (permalink / raw)
To: gang.chen.5i5j; +Cc: f.fainelli, netdev, linux-kernel, richard
In-Reply-To: <542FC3D9.4080607@gmail.com>
From: Chen Gang <gang.chen.5i5j@gmail.com>
Date: Sat, 04 Oct 2014 17:54:33 +0800
> MDIO_BCM_UNIMAC needs HAS_IOMEM, so depend on it, the related error (
> with allmodconfig under um):
>
> MODPOST 1205 modules
> ERROR: "devm_ioremap" [drivers/net/phy/mdio-bcm-unimac.ko] undefined!
>
> Signed-off-by: Chen Gang <gang.chen.5i5j@gmail.com>
Applied, thanks.
^ permalink raw reply
* Re: [PATCH net-next] net: skb_segment() provides list head and tail
From: David Miller @ 2014-10-06 4:38 UTC (permalink / raw)
To: eric.dumazet
Cc: brouer, netdev, therbert, hannes, fw, dborkman, jhs,
alexander.duyck, john.r.fastabend
In-Reply-To: <1412395159.17245.33.camel@edumazet-glaptop2.roam.corp.google.com>
From: Eric Dumazet <eric.dumazet@gmail.com>
Date: Fri, 03 Oct 2014 20:59:19 -0700
> From: Eric Dumazet <edumazet@google.com>
>
> Its unfortunate we have to walk again skb list to find the tail
> after segmentation, even if data is probably hot in cpu caches.
>
> skb_segment() can store the tail of the list into segs->prev,
> and validate_xmit_skb_list() can immediately get the tail.
>
> Signed-off-by: Eric Dumazet <edumazet@google.com>
Applied, thanks Eric.
^ permalink raw reply
* Re: [net-next v2 0/6] Add Geneve tunnel protocol support
From: David Miller @ 2014-10-06 4:32 UTC (permalink / raw)
To: azhou; +Cc: netdev
In-Reply-To: <1412375733-30981-1-git-send-email-azhou@nicira.com>
From: Andy Zhou <azhou@nicira.com>
Date: Fri, 3 Oct 2014 15:35:27 -0700
> This patch series adds kernel support for Geneve (Generic Network
> Virtualization Encapsulation) based on Geneve IETF draft:
> http://www.ietf.org/id/draft-gross-geneve-01.txt
>
> Patch 1 implements Geneve tunneling protocol driver
>
> Patch 2-6 adds openvswitch support for creating and using
> Geneve tunnels by OVS user space.
>
> ---
> v1->v2: Style fixes: use tab instead space for Kconfig
> Patch 2-6 are reviewed by Pravin Shetty, add him to acked-by
> Patch 6 was reviewed by Thomas Graf when commiting
> to openvswitch.org, add him to acked-by.
Series applied, thanks Andy.
^ permalink raw reply
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