Commit 0d613a27 authored by Frank Pavlic's avatar Frank Pavlic Committed by Jeff Garzik
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[PATCH] s390: lcs performance enhancements 



[patch 1/2] s390: lcs performance enhancements

From: Klaus Wacker <kdwacker@de.ibm.com>
	- When flood pinging (with large packet size) an LCS device,
	  about 90 % of all packets are dropped by driver.
	- increased number of lcs IO buffers to 32.
	- use netif_stop_queue/netif_wake_queue in lcs_start_xmit routine
	- don't lock the whole xmit routine but just the piece of code where
	  tx_buffer is touched.

Signed-off-by: default avatarFrank Pavlic <fpavlic@de.ibm.com>

diffstat:
 lcs.c |   31 +++++++++++++++++--------------
 lcs.h |    2 +-
 2 files changed, 18 insertions(+), 15 deletions(-)
Signed-off-by: default avatarJeff Garzik <jgarzik@pobox.com>
parent ca5b0ec8

drivers/s390/net/lcs.c

+17 −14
Original line number Diff line number Diff line
@@ -98,9 +98,9 @@ lcs_register_debug_facility(void) 
		return -ENOMEM;

	}

	debug_register_view(lcs_dbf_setup, &debug_hex_ascii_view);

	debug_set_level(lcs_dbf_setup, 4);

	debug_set_level(lcs_dbf_setup, 2);

	debug_register_view(lcs_dbf_trace, &debug_hex_ascii_view);

	debug_set_level(lcs_dbf_trace, 4);

	debug_set_level(lcs_dbf_trace, 2);

	return 0;

}
@@ -1292,10 +1292,9 @@ lcs_set_multicast_list(struct net_device *dev) 
        LCS_DBF_TEXT(4, trace, "setmulti");

        card = (struct lcs_card *) dev->priv;



        if (!lcs_set_thread_start_bit(card, LCS_SET_MC_THREAD)) {

        if (!lcs_set_thread_start_bit(card, LCS_SET_MC_THREAD)) 

		schedule_work(&card->kernel_thread_starter);

}

}



#endif /* CONFIG_IP_MULTICAST */
@@ -1459,6 +1458,8 @@ lcs_txbuffer_cb(struct lcs_channel *channel, struct lcs_buffer *buffer) 
	lcs_release_buffer(channel, buffer);

	card = (struct lcs_card *)

		((char *) channel - offsetof(struct lcs_card, write));

	if (netif_queue_stopped(card->dev))

		netif_wake_queue(card->dev);

	spin_lock(&card->lock);

	card->tx_emitted--;

	if (card->tx_emitted <= 0 && card->tx_buffer != NULL)
@@ -1478,6 +1479,7 @@ __lcs_start_xmit(struct lcs_card *card, struct sk_buff *skb, 
		 struct net_device *dev)

{

	struct lcs_header *header;

	int rc = 0;



	LCS_DBF_TEXT(5, trace, "hardxmit");

	if (skb == NULL) {
@@ -1492,10 +1494,8 @@ __lcs_start_xmit(struct lcs_card *card, struct sk_buff *skb, 
		card->stats.tx_carrier_errors++;

		return 0;

	}

	if (netif_queue_stopped(dev) ) {

		card->stats.tx_dropped++;

		return -EBUSY;

	}

	netif_stop_queue(card->dev);

	spin_lock(&card->lock);

	if (card->tx_buffer != NULL &&

	    card->tx_buffer->count + sizeof(struct lcs_header) +

	    skb->len + sizeof(u16) > LCS_IOBUFFERSIZE)
@@ -1506,7 +1506,8 @@ __lcs_start_xmit(struct lcs_card *card, struct sk_buff *skb, 
		card->tx_buffer = lcs_get_buffer(&card->write);

		if (card->tx_buffer == NULL) {

			card->stats.tx_dropped++;

			return -EBUSY;

			rc = -EBUSY;

			goto out;

		}

		card->tx_buffer->callback = lcs_txbuffer_cb;

		card->tx_buffer->count = 0;
@@ -1518,13 +1519,18 @@ __lcs_start_xmit(struct lcs_card *card, struct sk_buff *skb, 
	header->type = card->lan_type;

	header->slot = card->portno;

	memcpy(header + 1, skb->data, skb->len);

	spin_unlock(&card->lock);

	card->stats.tx_bytes += skb->len;

	card->stats.tx_packets++;

	dev_kfree_skb(skb);

	if (card->tx_emitted <= 0)

	netif_wake_queue(card->dev);

	spin_lock(&card->lock);

	if (card->tx_emitted <= 0 && card->tx_buffer != NULL)

		/* If this is the first tx buffer emit it immediately. */

		__lcs_emit_txbuffer(card);

	return 0;

out:

	spin_unlock(&card->lock);

	return rc;

}



static int
@@ -1535,9 +1541,7 @@ lcs_start_xmit(struct sk_buff *skb, struct net_device *dev) 


	LCS_DBF_TEXT(5, trace, "pktxmit");

	card = (struct lcs_card *) dev->priv;

	spin_lock(&card->lock);

	rc = __lcs_start_xmit(card, skb, dev);

	spin_unlock(&card->lock);

	return rc;

}
@@ -2319,7 +2323,6 @@ __init lcs_init_module(void) 
		PRINT_ERR("Initialization failed\n");

		return rc;

	}



	return 0;

}

drivers/s390/net/lcs.h

+1 −1
Original line number Diff line number Diff line
@@ -95,7 +95,7 @@ do { \ 
 */

#define LCS_ILLEGAL_OFFSET		0xffff

#define LCS_IOBUFFERSIZE		0x5000

#define LCS_NUM_BUFFS			8	/* needs to be power of 2 */

#define LCS_NUM_BUFFS			32	/* needs to be power of 2 */

#define LCS_MAC_LENGTH			6

#define LCS_INVALID_PORT_NO		-1

#define LCS_LANCMD_TIMEOUT_DEFAULT      5

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