Date: Fri, 18 Feb 2011 20:38:05 +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: r218820 - head/sys/dev/dc Message-ID: <201102182038.p1IKc5Mk071503@svn.freebsd.org>
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Author: yongari Date: Fri Feb 18 20:38:05 2011 New Revision: 218820 URL: http://svn.freebsd.org/changeset/base/218820 Log: For controllers that have TX interrupt moderation capability, request TX completion interrupt for every 8-th frames. Previously dc(4) requested TX completion interrupt if number of queued TX descriptors is greater than 64. This caused a lot of TX completion interrupt under high TX load once driver queued more than 64 TX descriptors. It's quite normal to see more than 64 queued TX descriptors under high TX load. This change reduces the number of TX completion interrupts to be less than 17k under high TX load. Because this change does not generate TX completion interrupt for each frame, add reclaiming transmitted buffers in dc_tick not to generate false watchdog timeouts. While I'm here add check for queued descriptors in dc_txeof() since there is no more work to do when there is no pending descriptors. Modified: head/sys/dev/dc/if_dc.c head/sys/dev/dc/if_dcreg.h Modified: head/sys/dev/dc/if_dc.c ============================================================================== --- head/sys/dev/dc/if_dc.c Fri Feb 18 20:37:09 2011 (r218819) +++ head/sys/dev/dc/if_dc.c Fri Feb 18 20:38:05 2011 (r218820) @@ -2473,6 +2473,7 @@ dc_list_tx_init(struct dc_softc *sc) } cd->dc_tx_prod = cd->dc_tx_cons = cd->dc_tx_cnt = 0; + cd->dc_tx_pkts = 0; bus_dmamap_sync(sc->dc_ltag, sc->dc_lmap, BUS_DMASYNC_PREWRITE | BUS_DMASYNC_PREREAD); return (0); @@ -2841,6 +2842,9 @@ dc_txeof(struct dc_softc *sc) int idx; u_int32_t ctl, txstat; + if (sc->dc_cdata.dc_tx_cnt == 0) + return; + ifp = sc->dc_ifp; /* @@ -2952,6 +2956,13 @@ dc_tick(void *xsc) ifp = sc->dc_ifp; mii = device_get_softc(sc->dc_miibus); + /* + * Reclaim transmitted frames for controllers that do + * not generate TX completion interrupt for every frame. + */ + if (sc->dc_flags & DC_TX_USE_TX_INTR) + dc_txeof(sc); + if (sc->dc_flags & DC_REDUCED_MII_POLL) { if (sc->dc_flags & DC_21143_NWAY) { r = CSR_READ_4(sc, DC_10BTSTAT); @@ -3322,8 +3333,11 @@ dc_encap(struct dc_softc *sc, struct mbu htole32(DC_TXCTL_FINT); if (sc->dc_flags & DC_TX_INTR_ALWAYS) sc->dc_ldata->dc_tx_list[cur].dc_ctl |= htole32(DC_TXCTL_FINT); - if (sc->dc_flags & DC_TX_USE_TX_INTR && sc->dc_cdata.dc_tx_cnt > 64) + if (sc->dc_flags & DC_TX_USE_TX_INTR && + ++sc->dc_cdata.dc_tx_pkts >= 8) { + sc->dc_cdata.dc_tx_pkts = 0; sc->dc_ldata->dc_tx_list[cur].dc_ctl |= htole32(DC_TXCTL_FINT); + } sc->dc_ldata->dc_tx_list[first].dc_status = htole32(DC_TXSTAT_OWN); bus_dmamap_sync(sc->dc_mtag, sc->dc_cdata.dc_tx_map[idx], Modified: head/sys/dev/dc/if_dcreg.h ============================================================================== --- head/sys/dev/dc/if_dcreg.h Fri Feb 18 20:37:09 2011 (r218819) +++ head/sys/dev/dc/if_dcreg.h Fri Feb 18 20:38:05 2011 (r218820) @@ -495,6 +495,7 @@ struct dc_chain_data { bus_dmamap_t dc_tx_map[DC_TX_LIST_CNT]; u_int32_t *dc_sbuf; u_int8_t dc_pad[DC_MIN_FRAMELEN]; + int dc_tx_pkts; int dc_tx_first; int dc_tx_prod; int dc_tx_cons;
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