[ofa-general] [PATCH RFC-repost] ipoib/cm: use common cq for ipoib TX
Michael S. Tsirkin
mst at dev.mellanox.co.il
Fri Apr 27 08:27:46 PDT 2007
Use common CQ for all TX QPs: keep a per-device counter of outstanding
tx WRs, and stop the interface when this counter reaches the send queue size, to
avoid CQ overruns.
This should help reduce the number of interrupts for bi-directional traffic
(such as TCP).
Signed-off-by: Michael S. Tsirkin <mst at mellanox.co.il>
---
> > Quoting Michael S. Tsirkin <mst at mellanox.co.il>:
> > Subject: [PATCH RFC] use common cq for ipoib cm send side
> >
> > The following untested patch moves all TX processing in IPoIB CM to common CQ.
> > This should help reduce the number of interrupts for bi-directional traffic
> > (such as TCP). Is this a good idea? What do others think?
> >
> > Signed-off-by: Michael S. Tsirkin <mst at mellanox.co.il>
>
> FYI, this was just thinking aloud. The version below works fine here but the
> performance gain seems to be very small (about 1%). The gain with NAPI might
> be bigger but this is yet to be tested. I'll continue looking into this.
>
> Feedback wellcome.
>
> ipoib.h | 10 +++++--
> ipoib_cm.c | 78 +++++++++++++++--------------------------------------------
> ipoib_ib.c | 28 ++++++++++++---------
> ipoib_main.c | 2 -
> 4 files changed, 45 insertions(+), 73 deletions(-)
I am reposting this patch because I think it will be needed on top
of NAPI patch, to help fix "driver is hogging interrupts" errors
reported for IPoIB send side.
See https://bugs.openfabrics.org/show_bug.cgi?id=508
diff --git a/drivers/infiniband/ulp/ipoib/ipoib.h b/drivers/infiniband/ulp/ipoib/ipoib.h
index eb885ee..ef703c7 100644
--- a/drivers/infiniband/ulp/ipoib/ipoib.h
+++ b/drivers/infiniband/ulp/ipoib/ipoib.h
@@ -99,9 +99,9 @@ enum {
#define IPOIB_OP_RECV (1ul << 31)
#ifdef CONFIG_INFINIBAND_IPOIB_CM
-#define IPOIB_CM_OP_SRQ (1ul << 30)
+#define IPOIB_OP_CM (1ul << 30)
#else
-#define IPOIB_CM_OP_SRQ (0)
+#define IPOIB_OP_CM (0)
#endif
/* structs */
@@ -144,7 +144,6 @@ struct ipoib_cm_rx {
struct ipoib_cm_tx {
struct ib_cm_id *id;
- struct ib_cq *cq;
struct ib_qp *qp;
struct list_head list;
struct net_device *dev;
@@ -233,6 +232,7 @@ struct ipoib_dev_priv {
unsigned tx_tail;
struct ib_sge tx_sge;
struct ib_send_wr tx_wr;
+ unsigned tx_outstanding;
struct ib_wc ibwc[IPOIB_NUM_WC];
@@ -439,6 +439,7 @@ void ipoib_cm_destroy_tx(struct ipoib_cm_tx *tx);
void ipoib_cm_skb_too_long(struct net_device* dev, struct sk_buff *skb,
unsigned int mtu);
void ipoib_cm_handle_rx_wc(struct net_device *dev, struct ib_wc *wc);
+void ipoib_cm_handle_tx_wc(struct net_device *dev, struct ib_wc *wc);
#else
struct ipoib_cm_tx;
@@ -527,6 +528,9 @@ static inline void ipoib_cm_handle_rx_wc(struct net_device *dev, struct ib_wc *w
{
}
+static inline void ipoib_cm_handle_tx_wc(struct net_device *dev, struct ib_wc *wc)
+{
+}
#endif
#ifdef CONFIG_INFINIBAND_IPOIB_DEBUG
diff --git a/drivers/infiniband/ulp/ipoib/ipoib_cm.c b/drivers/infiniband/ulp/ipoib/ipoib_cm.c
index 8ee6f06..af36562 100644
--- a/drivers/infiniband/ulp/ipoib/ipoib_cm.c
+++ b/drivers/infiniband/ulp/ipoib/ipoib_cm.c
@@ -85,7 +85,7 @@ static int ipoib_cm_post_receive(struct net_device *dev, int id)
struct ib_recv_wr *bad_wr;
int i, ret;
- priv->cm.rx_wr.wr_id = id | IPOIB_CM_OP_SRQ;
+ priv->cm.rx_wr.wr_id = id | IPOIB_OP_CM | IPOIB_OP_RECV;
for (i = 0; i < IPOIB_CM_RX_SG; ++i)
priv->cm.rx_sge[i].addr = priv->cm.srq_ring[id].mapping[i];
@@ -346,7 +346,7 @@ static void skb_put_frags(struct sk_buff *skb, unsigned int hdr_space,
void ipoib_cm_handle_rx_wc(struct net_device *dev, struct ib_wc *wc)
{
struct ipoib_dev_priv *priv = netdev_priv(dev);
- unsigned int wr_id = wc->wr_id & ~IPOIB_CM_OP_SRQ;
+ unsigned int wr_id = wc->wr_id & ~(IPOIB_OP_CM | IPOIB_OP_RECV);
struct sk_buff *skb;
struct ipoib_cm_rx *p;
unsigned long flags;
@@ -433,7 +433,7 @@ static inline int post_send(struct ipoib_dev_priv *priv,
priv->tx_sge.addr = addr;
priv->tx_sge.length = len;
- priv->tx_wr.wr_id = wr_id;
+ priv->tx_wr.wr_id = wr_id | IPOIB_OP_CM;
return ib_post_send(tx->qp, &priv->tx_wr, &bad_wr);
}
@@ -484,20 +484,19 @@ void ipoib_cm_send(struct net_device *dev, struct sk_buff *skb, struct ipoib_cm_
dev->trans_start = jiffies;
++tx->tx_head;
- if (tx->tx_head - tx->tx_tail == ipoib_sendq_size) {
+ if (++priv->tx_outstanding == ipoib_sendq_size) {
ipoib_dbg(priv, "TX ring 0x%x full, stopping kernel net queue\n",
tx->qp->qp_num);
netif_stop_queue(dev);
- set_bit(IPOIB_FLAG_NETIF_STOPPED, &tx->flags);
}
}
}
-static void ipoib_cm_handle_tx_wc(struct net_device *dev, struct ipoib_cm_tx *tx,
- struct ib_wc *wc)
+void ipoib_cm_handle_tx_wc(struct net_device *dev, struct ib_wc *wc)
{
struct ipoib_dev_priv *priv = netdev_priv(dev);
- unsigned int wr_id = wc->wr_id;
+ struct ipoib_cm_tx *tx = wc->qp->qp_context;
+ unsigned int wr_id = wc->wr_id & ~IPOIB_OP_CM;
struct ipoib_tx_buf *tx_req;
unsigned long flags;
@@ -522,11 +521,10 @@ static void ipoib_cm_handle_tx_wc(struct net_device *dev, struct ipoib_cm_tx *tx
spin_lock_irqsave(&priv->tx_lock, flags);
++tx->tx_tail;
- if (unlikely(test_bit(IPOIB_FLAG_NETIF_STOPPED, &tx->flags)) &&
- tx->tx_head - tx->tx_tail <= ipoib_sendq_size >> 1) {
- clear_bit(IPOIB_FLAG_NETIF_STOPPED, &tx->flags);
+ if (unlikely(--priv->tx_outstanding == ipoib_sendq_size >> 1) &&
+ netif_queue_stopped(dev) &&
+ test_bit(IPOIB_FLAG_ADMIN_UP, &priv->flags))
netif_wake_queue(dev);
- }
if (wc->status != IB_WC_SUCCESS &&
wc->status != IB_WC_WR_FLUSH_ERR) {
@@ -549,11 +547,6 @@ static void ipoib_cm_handle_tx_wc(struct net_device *dev, struct ipoib_cm_tx *tx
tx->neigh = NULL;
}
- /* queue would be re-started anyway when TX is destroyed,
- * but it makes sense to do it ASAP here. */
- if (test_and_clear_bit(IPOIB_FLAG_NETIF_STOPPED, &tx->flags))
- netif_wake_queue(dev);
-
if (test_and_clear_bit(IPOIB_FLAG_INITIALIZED, &tx->flags)) {
list_move(&tx->list, &priv->cm.reap_list);
queue_work(ipoib_workqueue, &priv->cm.reap_task);
@@ -567,19 +560,6 @@ static void ipoib_cm_handle_tx_wc(struct net_device *dev, struct ipoib_cm_tx *tx
spin_unlock_irqrestore(&priv->tx_lock, flags);
}
-static void ipoib_cm_tx_completion(struct ib_cq *cq, void *tx_ptr)
-{
- struct ipoib_cm_tx *tx = tx_ptr;
- int n, i;
-
- ib_req_notify_cq(cq, IB_CQ_NEXT_COMP);
- do {
- n = ib_poll_cq(cq, IPOIB_NUM_WC, tx->ibwc);
- for (i = 0; i < n; ++i)
- ipoib_cm_handle_tx_wc(tx->dev, tx, tx->ibwc + i);
- } while (n == IPOIB_NUM_WC);
-}
-
int ipoib_cm_dev_open(struct net_device *dev)
{
struct ipoib_dev_priv *priv = netdev_priv(dev);
@@ -699,17 +679,18 @@ static int ipoib_cm_rep_handler(struct ib_cm_id *cm_id, struct ib_cm_event *even
return 0;
}
-static struct ib_qp *ipoib_cm_create_tx_qp(struct net_device *dev, struct ib_cq *cq)
+static struct ib_qp *ipoib_cm_create_tx_qp(struct net_device *dev, struct ipoib_cm_tx *tx)
{
struct ipoib_dev_priv *priv = netdev_priv(dev);
struct ib_qp_init_attr attr = {};
attr.recv_cq = priv->cq;
+ attr.send_cq = priv->cq;
attr.srq = priv->cm.srq;
attr.cap.max_send_wr = ipoib_sendq_size;
attr.cap.max_send_sge = 1;
attr.sq_sig_type = IB_SIGNAL_ALL_WR;
attr.qp_type = IB_QPT_RC;
- attr.send_cq = cq;
+ attr.qp_context = tx;
return ib_create_qp(priv->pd, &attr);
}
@@ -789,21 +770,7 @@ static int ipoib_cm_tx_init(struct ipoib_cm_tx *p, u32 qpn,
goto err_tx;
}
- p->cq = ib_create_cq(priv->ca, ipoib_cm_tx_completion, NULL, p,
- ipoib_sendq_size + 1);
- if (IS_ERR(p->cq)) {
- ret = PTR_ERR(p->cq);
- ipoib_warn(priv, "failed to allocate tx cq: %d\n", ret);
- goto err_cq;
- }
-
- ret = ib_req_notify_cq(p->cq, IB_CQ_NEXT_COMP);
- if (ret) {
- ipoib_warn(priv, "failed to request completion notification: %d\n", ret);
- goto err_req_notify;
- }
-
- p->qp = ipoib_cm_create_tx_qp(p->dev, p->cq);
+ p->qp = ipoib_cm_create_tx_qp(p->dev, p);
if (IS_ERR(p->qp)) {
ret = PTR_ERR(p->qp);
ipoib_warn(priv, "failed to allocate tx qp: %d\n", ret);
@@ -840,12 +807,8 @@ err_modify:
err_id:
p->id = NULL;
ib_destroy_qp(p->qp);
-err_req_notify:
err_qp:
p->qp = NULL;
- ib_destroy_cq(p->cq);
-err_cq:
- p->cq = NULL;
err_tx:
return ret;
}
@@ -854,6 +817,7 @@ static void ipoib_cm_tx_destroy(struct ipoib_cm_tx *p)
{
struct ipoib_dev_priv *priv = netdev_priv(p->dev);
struct ipoib_tx_buf *tx_req;
+ unsigned long flags;
ipoib_dbg(priv, "Destroy active connection 0x%x head 0x%x tail 0x%x\n",
p->qp ? p->qp->qp_num : 0, p->tx_head, p->tx_tail);
@@ -864,12 +828,6 @@ static void ipoib_cm_tx_destroy(struct ipoib_cm_tx *p)
if (p->qp)
ib_destroy_qp(p->qp);
- if (p->cq)
- ib_destroy_cq(p->cq);
-
- if (test_bit(IPOIB_FLAG_NETIF_STOPPED, &p->flags))
- netif_wake_queue(p->dev);
-
if (p->tx_ring) {
while ((int) p->tx_tail - (int) p->tx_head < 0) {
tx_req = &p->tx_ring[p->tx_tail & (ipoib_sendq_size - 1)];
@@ -877,6 +835,12 @@ static void ipoib_cm_tx_destroy(struct ipoib_cm_tx *p)
DMA_TO_DEVICE);
dev_kfree_skb_any(tx_req->skb);
++p->tx_tail;
+ spin_lock_irqsave(&priv->tx_lock, flags);
+ if (unlikely(--priv->tx_outstanding == ipoib_sendq_size >> 1) &&
+ netif_queue_stopped(p->dev) &&
+ test_bit(IPOIB_FLAG_ADMIN_UP, &priv->flags))
+ netif_wake_queue(p->dev);
+ spin_unlock_irqrestore(&priv->tx_lock, flags);
}
kfree(p->tx_ring);
diff --git a/drivers/infiniband/ulp/ipoib/ipoib_ib.c b/drivers/infiniband/ulp/ipoib/ipoib_ib.c
index f2aa923..19a3d3e 100644
--- a/drivers/infiniband/ulp/ipoib/ipoib_ib.c
+++ b/drivers/infiniband/ulp/ipoib/ipoib_ib.c
@@ -266,11 +266,10 @@ static void ipoib_ib_handle_tx_wc(struct net_device *dev, struct ib_wc *wc)
spin_lock_irqsave(&priv->tx_lock, flags);
++priv->tx_tail;
- if (unlikely(test_bit(IPOIB_FLAG_NETIF_STOPPED, &priv->flags)) &&
- priv->tx_head - priv->tx_tail <= ipoib_sendq_size >> 1) {
- clear_bit(IPOIB_FLAG_NETIF_STOPPED, &priv->flags);
+ if (unlikely(--priv->tx_outstanding == ipoib_sendq_size >> 1) &&
+ netif_queue_stopped(dev) &&
+ test_bit(IPOIB_FLAG_ADMIN_UP, &priv->flags))
netif_wake_queue(dev);
- }
spin_unlock_irqrestore(&priv->tx_lock, flags);
if (wc->status != IB_WC_SUCCESS &&
@@ -282,12 +281,17 @@ static void ipoib_ib_handle_tx_wc(struct net_device *dev, struct ib_wc *wc)
static void ipoib_ib_handle_wc(struct net_device *dev, struct ib_wc *wc)
{
- if (wc->wr_id & IPOIB_CM_OP_SRQ)
- ipoib_cm_handle_rx_wc(dev, wc);
- else if (wc->wr_id & IPOIB_OP_RECV)
- ipoib_ib_handle_rx_wc(dev, wc);
- else
- ipoib_ib_handle_tx_wc(dev, wc);
+ if (wc->wr_id & IPOIB_OP_CM) {
+ if (wc->wr_id & IPOIB_OP_RECV)
+ ipoib_cm_handle_rx_wc(dev, wc);
+ else
+ ipoib_cm_handle_tx_wc(dev, wc);
+ } else {
+ if (wc->wr_id & IPOIB_OP_RECV)
+ ipoib_ib_handle_rx_wc(dev, wc);
+ else
+ ipoib_ib_handle_tx_wc(dev, wc);
+ }
}
void ipoib_ib_completion(struct ib_cq *cq, void *dev_ptr)
@@ -370,10 +374,9 @@ void ipoib_send(struct net_device *dev, struct sk_buff *skb,
address->last_send = priv->tx_head;
++priv->tx_head;
- if (priv->tx_head - priv->tx_tail == ipoib_sendq_size) {
+ if (++priv->tx_outstanding == ipoib_sendq_size) {
ipoib_dbg(priv, "TX ring full, stopping kernel net queue\n");
netif_stop_queue(dev);
- set_bit(IPOIB_FLAG_NETIF_STOPPED, &priv->flags);
}
}
}
@@ -549,6 +552,7 @@ int ipoib_ib_dev_stop(struct net_device *dev)
DMA_TO_DEVICE);
dev_kfree_skb_any(tx_req->skb);
++priv->tx_tail;
+ --priv->tx_outstanding;
}
for (i = 0; i < ipoib_recvq_size; ++i) {
diff --git a/drivers/infiniband/ulp/ipoib/ipoib_main.c b/drivers/infiniband/ulp/ipoib/ipoib_main.c
index 19e82db..7c7b136 100644
--- a/drivers/infiniband/ulp/ipoib/ipoib_main.c
+++ b/drivers/infiniband/ulp/ipoib/ipoib_main.c
@@ -900,7 +900,7 @@ int ipoib_dev_init(struct net_device *dev, struct ib_device *ca, int port)
goto out_rx_ring_cleanup;
}
- /* priv->tx_head & tx_tail are already 0 */
+ /* priv->tx_head, tx_tail & tx_outstanding are already 0 */
if (ipoib_ib_dev_init(dev, ca, port))
goto out_tx_ring_cleanup;
--
MST
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