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Date: Mon, 8 Jan 2007 11:26:12 -0800
From: Stephen Hemminger <shemminger@...l.org>
To: Jeff Garzik <jgarzik@...ox.com>
Cc: netdev@...r.kernel.org
Subject: [PATCH 3/3] chelsio: more rx speedup
Cleanup receive processing some more:
* do the reserve padding of skb during setup
* don't pass constants to get_packet
* do smart prefetch of skb
* make copybreak a module parameter
Signed-off-by: Stephen Hemminger <shemminger@...l.org>
---
drivers/net/chelsio/sge.c | 87 +++++++++++++++++++++++-----------------------
1 file changed, 45 insertions(+), 42 deletions(-)
--- netdev-2.6.orig/drivers/net/chelsio/sge.c
+++ netdev-2.6/drivers/net/chelsio/sge.c
@@ -71,12 +71,9 @@
#define SGE_FREEL_REFILL_THRESH 16
#define SGE_RESPQ_E_N 1024
#define SGE_INTRTIMER_NRES 1000
-#define SGE_RX_COPY_THRES 256
#define SGE_RX_SM_BUF_SIZE 1536
#define SGE_TX_DESC_MAX_PLEN 16384
-# define SGE_RX_DROP_THRES 2
-
#define SGE_RESPQ_REPLENISH_THRES (SGE_RESPQ_E_N / 4)
/*
@@ -846,6 +843,8 @@ static void refill_free_list(struct sge
skb_reserve(skb, q->dma_offset);
mapping = pci_map_single(pdev, skb->data, dma_len,
PCI_DMA_FROMDEVICE);
+ skb_reserve(skb, sge->rx_pkt_pad);
+
ce->skb = skb;
pci_unmap_addr_set(ce, dma_addr, mapping);
pci_unmap_len_set(ce, dma_len, dma_len);
@@ -1024,6 +1023,10 @@ static void recycle_fl_buf(struct freelQ
}
}
+static int copybreak __read_mostly = 256;
+module_param(copybreak, int, 0);
+MODULE_PARM_DESC(copybreak, "Receive copy threshold");
+
/**
* get_packet - return the next ingress packet buffer
* @pdev: the PCI device that received the packet
@@ -1043,45 +1046,42 @@ static void recycle_fl_buf(struct freelQ
* be copied but there is no memory for the copy.
*/
static inline struct sk_buff *get_packet(struct pci_dev *pdev,
- struct freelQ *fl, unsigned int len,
- int dma_pad, int skb_pad,
- unsigned int copy_thres,
- unsigned int drop_thres)
+ struct freelQ *fl, unsigned int len)
{
struct sk_buff *skb;
- struct freelQ_ce *ce = &fl->centries[fl->cidx];
+ const struct freelQ_ce *ce = &fl->centries[fl->cidx];
- if (len < copy_thres) {
- skb = alloc_skb(len + skb_pad, GFP_ATOMIC);
- if (likely(skb != NULL)) {
- skb_reserve(skb, skb_pad);
- skb_put(skb, len);
- pci_dma_sync_single_for_cpu(pdev,
- pci_unmap_addr(ce, dma_addr),
- pci_unmap_len(ce, dma_len),
- PCI_DMA_FROMDEVICE);
- memcpy(skb->data, ce->skb->data + dma_pad, len);
- pci_dma_sync_single_for_device(pdev,
+ if (len < copybreak) {
+ skb = alloc_skb(len + 2, GFP_ATOMIC);
+ if (!skb)
+ goto use_orig_buf;
+
+ skb_reserve(skb, 2); /* align IP header */
+ skb_put(skb, len);
+ pci_dma_sync_single_for_cpu(pdev,
pci_unmap_addr(ce, dma_addr),
pci_unmap_len(ce, dma_len),
PCI_DMA_FROMDEVICE);
- } else if (!drop_thres)
- goto use_orig_buf;
-
+ memcpy(skb->data, ce->skb->data, len);
+ pci_dma_sync_single_for_device(pdev,
+ pci_unmap_addr(ce, dma_addr),
+ pci_unmap_len(ce, dma_len),
+ PCI_DMA_FROMDEVICE);
recycle_fl_buf(fl, fl->cidx);
return skb;
}
- if (fl->credits < drop_thres) {
+use_orig_buf:
+ if (fl->credits < 2) {
recycle_fl_buf(fl, fl->cidx);
return NULL;
}
-use_orig_buf:
pci_unmap_single(pdev, pci_unmap_addr(ce, dma_addr),
pci_unmap_len(ce, dma_len), PCI_DMA_FROMDEVICE);
skb = ce->skb;
- skb_reserve(skb, dma_pad);
+ prefetch(skb->data);
+
skb_put(skb, len);
return skb;
}
@@ -1359,27 +1359,25 @@ static void restart_sched(unsigned long
*
* Process an ingress ethernet pakcet and deliver it to the stack.
*/
-static int sge_rx(struct sge *sge, struct freelQ *fl, unsigned int len)
+static void sge_rx(struct sge *sge, struct freelQ *fl, unsigned int len)
{
struct sk_buff *skb;
- struct cpl_rx_pkt *p;
+ const struct cpl_rx_pkt *p;
struct adapter *adapter = sge->adapter;
struct sge_port_stats *st;
- skb = get_packet(adapter->pdev, fl, len - sge->rx_pkt_pad,
- sge->rx_pkt_pad, 2, SGE_RX_COPY_THRES,
- SGE_RX_DROP_THRES);
+ skb = get_packet(adapter->pdev, fl, len - sge->rx_pkt_pad);
if (unlikely(!skb)) {
sge->stats.rx_drops++;
- return 0;
+ return;
}
- p = (struct cpl_rx_pkt *)skb->data;
- skb_pull(skb, sizeof(*p));
+ p = (const struct cpl_rx_pkt *) skb->data;
if (p->iff >= adapter->params.nports) {
kfree_skb(skb);
- return 0;
+ return;
}
+ __skb_pull(skb, sizeof(*p));
skb->dev = adapter->port[p->iff].dev;
skb->dev->last_rx = jiffies;
@@ -1411,7 +1409,6 @@ static int sge_rx(struct sge *sge, struc
netif_rx(skb);
#endif
}
- return 0;
}
/*
@@ -1493,12 +1490,11 @@ static int process_responses(struct adap
struct sge *sge = adapter->sge;
struct respQ *q = &sge->respQ;
struct respQ_e *e = &q->entries[q->cidx];
- int budget_left = budget;
+ int done = 0;
unsigned int flags = 0;
unsigned int cmdq_processed[SGE_CMDQ_N] = {0, 0};
-
- while (likely(budget_left && e->GenerationBit == q->genbit)) {
+ while (done < budget && e->GenerationBit == q->genbit) {
flags |= e->Qsleeping;
cmdq_processed[0] += e->Cmdq0CreditReturn;
@@ -1508,14 +1504,16 @@ static int process_responses(struct adap
* ping-pong of TX state information on MP where the sender
* might run on a different CPU than this function...
*/
- if (unlikely(flags & F_CMDQ0_ENABLE || cmdq_processed[0] > 64)) {
+ if (unlikely((flags & F_CMDQ0_ENABLE) || cmdq_processed[0] > 64)) {
flags = update_tx_info(adapter, flags, cmdq_processed[0]);
cmdq_processed[0] = 0;
}
+
if (unlikely(cmdq_processed[1] > 16)) {
sge->cmdQ[1].processed += cmdq_processed[1];
cmdq_processed[1] = 0;
}
+
if (likely(e->DataValid)) {
struct freelQ *fl = &sge->freelQ[e->FreelistQid];
@@ -1525,12 +1523,16 @@ static int process_responses(struct adap
else
sge_rx(sge, fl, e->BufferLength);
+ ++done;
+
/*
* Note: this depends on each packet consuming a
* single free-list buffer; cf. the BUG above.
*/
if (++fl->cidx == fl->size)
fl->cidx = 0;
+ prefetch(fl->centries[fl->cidx].skb);
+
if (unlikely(--fl->credits <
fl->size - SGE_FREEL_REFILL_THRESH))
refill_free_list(sge, fl);
@@ -1549,14 +1551,12 @@ static int process_responses(struct adap
writel(q->credits, adapter->regs + A_SG_RSPQUEUECREDIT);
q->credits = 0;
}
- --budget_left;
}
flags = update_tx_info(adapter, flags, cmdq_processed[0]);
sge->cmdQ[1].processed += cmdq_processed[1];
- budget -= budget_left;
- return budget;
+ return done;
}
static inline int responses_pending(const struct adapter *adapter)
@@ -1581,11 +1581,14 @@ static int process_pure_responses(struct
struct sge *sge = adapter->sge;
struct respQ *q = &sge->respQ;
struct respQ_e *e = &q->entries[q->cidx];
+ const struct freelQ *fl = &sge->freelQ[e->FreelistQid];
unsigned int flags = 0;
unsigned int cmdq_processed[SGE_CMDQ_N] = {0, 0};
+ prefetch(fl->centries[fl->cidx].skb);
if (e->DataValid)
return 1;
+
do {
flags |= e->Qsleeping;
-
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