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Date:      Fri, 26 Feb 2010 18:18:02 +0000 (UTC)
From:      Pyun YongHyeon <yongari@FreeBSD.org>
To:        src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org
Subject:   svn commit: r204363 - head/sys/dev/msk
Message-ID:  <201002261818.o1QII2mU016012@svn.freebsd.org>
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Author: yongari
Date: Fri Feb 26 18:18:02 2010
New Revision: 204363
URL: http://svn.freebsd.org/changeset/base/204363

Log:
  Optimize inserting LE for TX checksum computation. Controller does
  not require checksum LE configuration if checksum start and write
  position is the same as before. So keep track last checksum start
  and write position and insert new LE whenever the position is
  changed. This reduces number of LEs used in TX path as well as
  slightly enhance TX performance.

Modified:
  head/sys/dev/msk/if_msk.c
  head/sys/dev/msk/if_mskreg.h

Modified: head/sys/dev/msk/if_msk.c
==============================================================================
--- head/sys/dev/msk/if_msk.c	Fri Feb 26 17:33:43 2010	(r204362)
+++ head/sys/dev/msk/if_msk.c	Fri Feb 26 18:18:02 2010	(r204363)
@@ -738,6 +738,7 @@ msk_init_tx_ring(struct msk_if_softc *sc
 	int i;
 
 	sc_if->msk_cdata.msk_tso_mtu = 0;
+	sc_if->msk_cdata.msk_last_csum = 0;
 	sc_if->msk_cdata.msk_tx_prod = 0;
 	sc_if->msk_cdata.msk_tx_cons = 0;
 	sc_if->msk_cdata.msk_tx_cnt = 0;
@@ -2530,7 +2531,7 @@ msk_encap(struct msk_if_softc *sc_if, st
 	struct mbuf *m;
 	bus_dmamap_t map;
 	bus_dma_segment_t txsegs[MSK_MAXTXSEGS];
-	uint32_t control, prod, si;
+	uint32_t control, csum, prod, si;
 	uint16_t offset, tcp_offset, tso_mtu;
 	int error, i, nseg, tso;
 
@@ -2709,17 +2710,22 @@ msk_encap(struct msk_if_softc *sc_if, st
 		if ((sc_if->msk_flags & MSK_FLAG_AUTOTX_CSUM) != 0)
 			control |= CALSUM;
 		else {
-			tx_le = &sc_if->msk_rdata.msk_tx_ring[prod];
-			tx_le->msk_addr = htole32(((tcp_offset +
-			    m->m_pkthdr.csum_data) & 0xffff) |
-			    ((uint32_t)tcp_offset << 16));
-			tx_le->msk_control = htole32(1 << 16 |
-			    (OP_TCPLISW | HW_OWNER));
-			control = CALSUM | WR_SUM | INIT_SUM | LOCK_SUM;
+			control |= CALSUM | WR_SUM | INIT_SUM | LOCK_SUM;
 			if ((m->m_pkthdr.csum_flags & CSUM_UDP) != 0)
 				control |= UDPTCP;
-			sc_if->msk_cdata.msk_tx_cnt++;
-			MSK_INC(prod, MSK_TX_RING_CNT);
+			/* Checksum write position. */
+			csum = (tcp_offset + m->m_pkthdr.csum_data) & 0xffff;
+			/* Checksum start position. */
+			csum |= (uint32_t)tcp_offset << 16;
+			if (csum != sc_if->msk_cdata.msk_last_csum) {
+				tx_le = &sc_if->msk_rdata.msk_tx_ring[prod];
+				tx_le->msk_addr = htole32(csum);
+				tx_le->msk_control = htole32(1 << 16 |
+				    (OP_TCPLISW | HW_OWNER));
+				sc_if->msk_cdata.msk_tx_cnt++;
+				MSK_INC(prod, MSK_TX_RING_CNT);
+				sc_if->msk_cdata.msk_last_csum = csum;
+			}
 		}
 	}
 

Modified: head/sys/dev/msk/if_mskreg.h
==============================================================================
--- head/sys/dev/msk/if_mskreg.h	Fri Feb 26 17:33:43 2010	(r204362)
+++ head/sys/dev/msk/if_mskreg.h	Fri Feb 26 18:18:02 2010	(r204363)
@@ -2361,6 +2361,7 @@ struct msk_chain_data {
 	bus_dmamap_t		msk_jumbo_rx_ring_map;
 	bus_dmamap_t		msk_jumbo_rx_sparemap;
 	uint16_t		msk_tso_mtu;
+	uint32_t		msk_last_csum;
 	int			msk_tx_prod;
 	int			msk_tx_cons;
 	int			msk_tx_cnt;

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