Messages in this thread Patch in this message | | | Date | Tue, 3 Oct 2006 16:03:04 -0500 | Subject | [PATCH 3/4]: Spidernet transmit interupt mitigation | From | (Linas Vepstas) |
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For small packets, the transmit interrupt settings were accidentally generating too many interrupts. This patch turns off all transmit-related interrupts when the tx queue is mostly empty.
Signed-off-by: Linas Vepstas <linas@austin.ibm.com> Cc: James K Lewis <jklewis@us.ibm.com> Cc: Arnd Bergmann <arnd@arndb.de>
---- drivers/net/spider_net.c | 8 +++++--- drivers/net/spider_net.h | 7 +++---- 2 files changed, 8 insertions(+), 7 deletions(-)
Index: linux-2.6.18-mm2/drivers/net/spider_net.c =================================================================== --- linux-2.6.18-mm2.orig/drivers/net/spider_net.c 2006-10-02 19:06:55.000000000 -0500 +++ linux-2.6.18-mm2/drivers/net/spider_net.c 2006-10-02 19:09:38.000000000 -0500 @@ -707,7 +707,9 @@ spider_net_set_low_watermark(struct spid descr = descr->next; cnt++; } - if (cnt == 0) + + /* If TX queue is short, don't even bother with interrupts */ + if (cnt < tx_descriptors/4) return; /* Set low-watermark 3/4th's of the way into the queue. */ @@ -716,7 +718,7 @@ spider_net_set_low_watermark(struct spid for (i=0;i<cnt; i++) descr = descr->next; - /* Set the new watermark, clear the old wtermark */ + /* Set the new watermark, clear the old watermark */ spin_lock_irqsave(&card->tx_chain.lock, flags); descr->dmac_cmd_status |= SPIDER_NET_DESCR_TXDESFLG; if (card->low_watermark && card->low_watermark != descr) @@ -1639,7 +1641,7 @@ spider_net_enable_card(struct spider_net SPIDER_NET_INT2_MASK_VALUE); spider_net_write_reg(card, SPIDER_NET_GDTDMACCNTR, - SPIDER_NET_GDTBSTA); + SPIDER_NET_GDTBSTA | SPIDER_NET_GDTDCEIDIS); } /** Index: linux-2.6.18-mm2/drivers/net/spider_net.h =================================================================== --- linux-2.6.18-mm2.orig/drivers/net/spider_net.h 2006-10-02 19:06:55.000000000 -0500 +++ linux-2.6.18-mm2/drivers/net/spider_net.h 2006-10-02 19:09:38.000000000 -0500 @@ -217,7 +217,8 @@ extern char spider_net_driver_name[]; #define SPIDER_NET_GDTBSTA 0x00000300 #define SPIDER_NET_GDTDCEIDIS 0x00000002 #define SPIDER_NET_DMA_TX_VALUE SPIDER_NET_TX_DMA_EN | \ - SPIDER_NET_GDTBSTA + SPIDER_NET_GDTBSTA | \ + SPIDER_NET_GDTDCEIDIS #define SPIDER_NET_DMA_TX_FEND_VALUE 0x00030003 /* SPIDER_NET_UA_DESCR_VALUE is OR'ed with the unicast address */ @@ -326,9 +327,7 @@ enum spider_net_int2_status { SPIDER_NET_GRISPDNGINT }; -#define SPIDER_NET_TXINT ( (1 << SPIDER_NET_GTTEDINT) | \ - (1 << SPIDER_NET_GDTDCEINT) | \ - (1 << SPIDER_NET_GDTFDCINT) ) +#define SPIDER_NET_TXINT ( (1 << SPIDER_NET_GDTFDCINT) ) /* we rely on flagged descriptor interrupts*/ #define SPIDER_NET_RXINT ( (1 << SPIDER_NET_GDAFDCINT) | \ - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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