> This is the second version of my patch that removes the expensive memcpy of
> received
> ethernet frames in interrupt context.
>
> I have 1 report(from Ricardo Scop) of 20% increase in packets/second, packet
> size 1500 when
> applied to 8260 FEC(needs to be applied manually). But min packet size
> decreased with 10 %.
> This version should fix the 10% decrease case.
>
> This patch could be adapted 8xx_io/fec.c and 8260_io/enet.c and
> 8260/fcc_enet.c with little effort.
>
> Better fix a bug in set_multicast_list(), move the dmi list forward when
> walking it(dmi = dmi->next;)
>
> New stuff:
> - Configrable: copy small packets or pass them directly, see
> COPY_SMALL_FRAMES in code.
> - Collision reporting fix form Thomas Lange.
> - Don't pass receive frames which has error upwards.
> - Report RX_OV errors as fifo errors, not crc errors.
>
> Please test and report any problems and performace improvements.
Hi
This is the third version of my optimized enet.c patch.
Changes since version 2:
1) invalidate the whole buffer BEFORE it is given to he CPM. Previously
it was invalidated after the packet was received and that could lead to
buffer
corruption in some cases.
2) use dma_cache_inv() instead of invalidate_dcache_range() since that will
work
for both 8xx and 82xx.
3) decrease the allocated buffer length.
4) disabled COPY_SMALL_FRAME. Define it somewhere if you want to save some
memory.
5) probably some white space changes got in too.
Any chance to see it the devel tree?
More than 3 months has passed since version 2 and the only problem reported was
1) and the fix has been know since mid November.
Dan, you said you would integrate this patch(or some version of it) in
November. I
think I have waited long enough now. Please do ASAP.
Jocke
--- arch/ppc/8xx_io/enet.c Fri Nov 1 14:44:05 2002
+++ arch/ppc/8xx_io/new_enet.c Sat Jan 25 19:57:50 2003
@@ -34,7 +34,6 @@
#include <linux/ioport.h>
#include <linux/slab.h>
#include <linux/interrupt.h>
-#include <linux/pci.h>
#include <linux/init.h>
#include <linux/delay.h>
#include <linux/netdevice.h>
@@ -86,6 +85,14 @@
* All functions are directly controlled using I/O pins. See <asm/commproc.h>.
*/
+/* Define COPY_SMALL_FRAMES if you want to save buffer memory for small packets
+ * at a small performance hit. Note performance testing needed */
+/* #define COPY_SMALL_FRAMES 1 */
+
+#ifdef COPY_SMALL_FRAMES
+ #define RX_COPYBREAK (256-16) /* dev_alloc_skb() adds 16 bytes for internal
use */
+#endif
+
/* The transmitter timeout
*/
#define TX_TIMEOUT (2*HZ)
@@ -97,19 +104,17 @@
* the skbuffer directly.
*/
#ifdef CONFIG_ENET_BIG_BUFFERS
-#define CPM_ENET_RX_PAGES 32
-#define CPM_ENET_RX_FRSIZE 2048
-#define CPM_ENET_RX_FRPPG (PAGE_SIZE / CPM_ENET_RX_FRSIZE)
-#define RX_RING_SIZE (CPM_ENET_RX_FRPPG * CPM_ENET_RX_PAGES)
-#define TX_RING_SIZE 64 /* Must be power of two */
-#define TX_RING_MOD_MASK 63 /* for this to work */
+ #define RX_RING_SIZE 64
+ #define TX_RING_SIZE 64 /* Must be power of two for this to
work */
#else
-#define CPM_ENET_RX_PAGES 4
-#define CPM_ENET_RX_FRSIZE 2048
-#define CPM_ENET_RX_FRPPG (PAGE_SIZE / CPM_ENET_RX_FRSIZE)
-#define RX_RING_SIZE (CPM_ENET_RX_FRPPG * CPM_ENET_RX_PAGES)
-#define TX_RING_SIZE 8 /* Must be power of two */
-#define TX_RING_MOD_MASK 7 /* for this to work */
+ #define RX_RING_SIZE 8
+ #define TX_RING_SIZE 8 /* Must be power of two for this to
work */
+#endif
+#define TX_RING_MOD_MASK (TX_RING_SIZE-1)
+
+#define CPM_ENET_RX_FRSIZE 1552 /* must be a multiple of cache line */
+#if CPM_ENET_RX_FRSIZE % L1_CACHE_LINE_SIZE != 0
+ #error CPM_ENET_RX_FRSIZE must be a multiple of L1 cache size
#endif
/* The CPM stores dest/src/type, data, and checksum for receive packets.
@@ -143,7 +148,7 @@
/* Virtual addresses for the receive buffers because we can't
* do a __va() on them anymore.
*/
- unsigned char *rx_vaddr[RX_RING_SIZE];
+ void *rx_vaddr[RX_RING_SIZE];
struct net_device_stats stats;
uint tx_full;
spinlock_t lock;
@@ -370,11 +375,11 @@
cep->stats.tx_packets++;
- /* Deferred means some collisions occurred during transmit,
- * but we eventually sent the packet OK.
- */
- if (bdp->cbd_sc & BD_ENET_TX_DEF)
- cep->stats.collisions++;
+ /* Check retry counter, i.e. collision counter */
+ if (bdp->cbd_sc & BD_ENET_TX_RCMASK){
+ /* Note that counter cannot go higher than 15 */
+ cep->stats.collisions+=(bdp->cbd_sc &
BD_ENET_TX_RCMASK)>>2;
+ }
/* Free the sk buffer associated with this last transmit.
*/
@@ -449,6 +454,7 @@
struct scc_enet_private *cep;
volatile cbd_t *bdp;
struct sk_buff *skb;
+ struct sk_buff *skb_tmp;
ushort pkt_len;
cep = (struct scc_enet_private *)dev->priv;
@@ -458,83 +464,93 @@
*/
bdp = cep->cur_rx;
-for (;;) {
- if (bdp->cbd_sc & BD_ENET_RX_EMPTY)
- break;
-
+ for (;;) {
+ if (bdp->cbd_sc & BD_ENET_RX_EMPTY)
+ break;
+
+#define RX_BD_ERRORS (BD_ENET_RX_LG | BD_ENET_RX_SH | BD_ENET_RX_NO |
BD_ENET_RX_CR | BD_ENET_RX_OV | BD_ENET_RX_CL)
#ifndef final_version
- /* Since we have allocated space to hold a complete frame, both
- * the first and last indicators should be set.
- */
- if ((bdp->cbd_sc & (BD_ENET_RX_FIRST | BD_ENET_RX_LAST)) !=
- (BD_ENET_RX_FIRST | BD_ENET_RX_LAST))
+ /* Since we have allocated space to hold a complete frame, both
+ * the first and last indicators should be set.
+ */
+ if ((bdp->cbd_sc & (BD_ENET_RX_FIRST | BD_ENET_RX_LAST)) !=
+ (BD_ENET_RX_FIRST | BD_ENET_RX_LAST))
printk("CPM ENET: rcv is not first+last\n");
#endif
-
- /* Frame too long or too short.
- */
- if (bdp->cbd_sc & (BD_ENET_RX_LG | BD_ENET_RX_SH))
- cep->stats.rx_length_errors++;
- if (bdp->cbd_sc & BD_ENET_RX_NO) /* Frame alignment */
- cep->stats.rx_frame_errors++;
- if (bdp->cbd_sc & BD_ENET_RX_CR) /* CRC Error */
- cep->stats.rx_crc_errors++;
- if (bdp->cbd_sc & BD_ENET_RX_OV) /* FIFO overrun */
- cep->stats.rx_crc_errors++;
-
- /* Report late collisions as a frame error.
- * On this error, the BD is closed, but we don't know what we
- * have in the buffer. So, just drop this frame on the floor.
- */
- if (bdp->cbd_sc & BD_ENET_RX_CL) {
- cep->stats.rx_frame_errors++;
- }
- else {
-
- /* Process the incoming frame.
- */
- cep->stats.rx_packets++;
- pkt_len = bdp->cbd_datlen;
- cep->stats.rx_bytes += pkt_len;
-
- /* This does 16 byte alignment, much more than we need.
- * The packet length includes FCS, but we don't want to
- * include that when passing upstream as it messes up
- * bridging applications.
- */
- skb = dev_alloc_skb(pkt_len-4);
-
- if (skb == NULL) {
- printk("%s: Memory squeeze, dropping packet.\n",
dev->name);
- cep->stats.rx_dropped++;
- }
- else {
- skb->dev = dev;
- skb_put(skb,pkt_len-4); /* Make room */
- eth_copy_and_sum(skb,
- cep->rx_vaddr[bdp - cep->rx_bd_base],
- pkt_len-4, 0);
- skb->protocol=eth_type_trans(skb,dev);
- netif_rx(skb);
+ if(bdp->cbd_sc & RX_BD_ERRORS){ /* Receive errors ? */
+ cep->stats.rx_errors++;
+ if (bdp->cbd_sc & (BD_ENET_RX_LG | BD_ENET_RX_SH)) /*
Frame too long or too short. */
+ cep->stats.rx_length_errors++;
+ if (bdp->cbd_sc & BD_ENET_RX_NO) /* Frame
alignment */
+ cep->stats.rx_frame_errors++;
+ if (bdp->cbd_sc & BD_ENET_RX_CR) /* CRC Error */
+ cep->stats.rx_crc_errors++;
+ if (bdp->cbd_sc & BD_ENET_RX_OV) /* FIFO overrun
*/
+ cep->stats.rx_fifo_errors++;
+ if (bdp->cbd_sc & BD_ENET_RX_CL) /* Late
collision */
+ cep->stats.collisions++;
+ } else {
+ /* Process the incoming frame.
+ */
+ cep->stats.rx_packets++;
+ pkt_len = bdp->cbd_datlen;
+ cep->stats.rx_bytes += pkt_len;
+ pkt_len -= 4; /* The packet length includes FCS, but we
don't want to
+ * include that when passing upstream as
it messes up
+ * bridging applications. Is this still
true ???? */
+#ifdef COPY_SMALL_FRAMES
+ /* Allocate the next buffer now so we are sure to have
one when needed
+ * This does 16 byte alignment, exactly what we
need(L1_CACHE aligned). */
+ if(pkt_len < RX_COPYBREAK)
+ skb_tmp = __dev_alloc_skb(pkt_len, GFP_ATOMIC |
GFP_DMA);
+ else
+#endif
+ skb_tmp = __dev_alloc_skb(CPM_ENET_RX_FRSIZE,
GFP_ATOMIC | GFP_DMA);
+
+ if (skb_tmp == NULL) {
+ printk("%s: Memory squeeze, dropping
packet.\n", dev->name);
+ cep->stats.rx_dropped++;
+
+ } else {
+ skb = cep->rx_vaddr[bdp - cep->rx_bd_base];
+#ifdef COPY_SMALL_FRAMES
+ if(pkt_len < RX_COPYBREAK) {
+ typeof(skb) skb_swap = skb;
+ memcpy(skb_put(skb_tmp, pkt_len),
skb->data, pkt_len);
+ /* swap the skb and skb_tmp */
+ skb = skb_tmp;
+ skb_tmp = skb_swap;
+ }
+ else
+#endif
+ {
+ skb_put(skb, pkt_len); /* Make room */
+ bdp->cbd_bufaddr = __pa(skb_tmp->data);
+ cep->rx_vaddr[bdp - cep->rx_bd_base] =
skb_tmp;
+ }
+ dma_cache_inv((unsigned long) skb_tmp->data,
CPM_ENET_RX_FRSIZE);
+ skb->dev = dev;
+ skb->protocol=eth_type_trans(skb, dev);
+ netif_rx(skb);
+ }
}
+
+ /* Clear the status flags for this buffer.
+ */
+ bdp->cbd_sc &= ~BD_ENET_RX_STATS;
+
+ /* Mark the buffer empty.
+ */
+ bdp->cbd_sc |= BD_ENET_RX_EMPTY;
+
+ /* Update BD pointer to next entry.
+ */
+ if (bdp->cbd_sc & BD_ENET_RX_WRAP)
+ bdp = cep->rx_bd_base;
+ else
+ bdp++;
+
}
-
- /* Clear the status flags for this buffer.
- */
- bdp->cbd_sc &= ~BD_ENET_RX_STATS;
-
- /* Mark the buffer empty.
- */
- bdp->cbd_sc |= BD_ENET_RX_EMPTY;
-
- /* Update BD pointer to next entry.
- */
- if (bdp->cbd_sc & BD_ENET_RX_WRAP)
- bdp = cep->rx_bd_base;
- else
- bdp++;
-
- }
cep->cur_rx = (cbd_t *)bdp;
return 0;
@@ -608,7 +624,7 @@
dmi = dev->mc_list;
- for (i=0; i<dev->mc_count; i++) {
+ for (i=0; i<dev->mc_count; i++, dmi = dmi->next) {
/* Only support group multicast for now.
*/
@@ -647,8 +663,7 @@
struct net_device *dev;
struct scc_enet_private *cep;
int i, j, k;
- unsigned char *eap, *ba;
- dma_addr_t mem_addr;
+ unsigned char *eap;
bd_t *bd;
volatile cbd_t *bdp;
volatile cpm8xx_t *cp;
@@ -839,22 +854,14 @@
bdp = cep->rx_bd_base;
k = 0;
- for (i=0; i<CPM_ENET_RX_PAGES; i++) {
-
- /* Allocate a page.
- */
- ba = (unsigned char *)consistent_alloc(GFP_KERNEL, PAGE_SIZE,
&mem_addr);
-
- /* Initialize the BD for every fragment in the page.
- */
- for (j=0; j<CPM_ENET_RX_FRPPG; j++) {
- bdp->cbd_sc = BD_ENET_RX_EMPTY | BD_ENET_RX_INTR;
- bdp->cbd_bufaddr = mem_addr;
- cep->rx_vaddr[k++] = ba;
- mem_addr += CPM_ENET_RX_FRSIZE;
- ba += CPM_ENET_RX_FRSIZE;
- bdp++;
- }
+ /* Initialize the BDs. */
+ for (j=0; j < RX_RING_SIZE; j++) {
+ struct sk_buff * skb = __dev_alloc_skb(CPM_ENET_RX_FRSIZE,
GFP_ATOMIC | GFP_DMA);
+ dma_cache_inv((unsigned long) skb->data, CPM_ENET_RX_FRSIZE);
+ bdp->cbd_sc = BD_ENET_RX_EMPTY | BD_ENET_RX_INTR;
+ bdp->cbd_bufaddr = __pa(skb->data);
+ cep->rx_vaddr[k++] = skb;
+ bdp++;
}
/* Set the last buffer to wrap.
** Sent via the linuxppc-embedded mail list. See http://lists.linuxppc.org/
