From owner-svn-src-user@FreeBSD.ORG Mon Jan 12 04:12:47 2009 Return-Path: Delivered-To: svn-src-user@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 54C451065695; Mon, 12 Jan 2009 04:12:47 +0000 (UTC) (envelope-from kmacy@FreeBSD.org) Received: from svn.freebsd.org (svn.freebsd.org [IPv6:2001:4f8:fff6::2c]) by mx1.freebsd.org (Postfix) with ESMTP id 433A68FC1B; Mon, 12 Jan 2009 04:12:47 +0000 (UTC) (envelope-from kmacy@FreeBSD.org) Received: from svn.freebsd.org (localhost [127.0.0.1]) by svn.freebsd.org (8.14.3/8.14.3) with ESMTP id n0C4Clqc049947; Mon, 12 Jan 2009 04:12:47 GMT (envelope-from kmacy@svn.freebsd.org) Received: (from kmacy@localhost) by svn.freebsd.org (8.14.3/8.14.3/Submit) id n0C4ClsC049946; Mon, 12 Jan 2009 04:12:47 GMT (envelope-from kmacy@svn.freebsd.org) Message-Id: <200901120412.n0C4ClsC049946@svn.freebsd.org> From: Kip Macy Date: Mon, 12 Jan 2009 04:12:47 +0000 (UTC) To: src-committers@freebsd.org, svn-src-user@freebsd.org X-SVN-Group: user MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Cc: Subject: svn commit: r187084 - user/kmacy/HEAD_fast_net/sys/dev/mxge X-BeenThere: svn-src-user@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: "SVN commit messages for the experimental " user" src tree" List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 12 Jan 2009 04:12:48 -0000 Author: kmacy Date: Mon Jan 12 04:12:46 2009 New Revision: 187084 URL: http://svn.freebsd.org/changeset/base/187084 Log: reduce the cost of mxge_intr by adding prefetches Modified: user/kmacy/HEAD_fast_net/sys/dev/mxge/if_mxge.c Modified: user/kmacy/HEAD_fast_net/sys/dev/mxge/if_mxge.c ============================================================================== --- user/kmacy/HEAD_fast_net/sys/dev/mxge/if_mxge.c Mon Jan 12 04:10:40 2009 (r187083) +++ user/kmacy/HEAD_fast_net/sys/dev/mxge/if_mxge.c Mon Jan 12 04:12:46 2009 (r187084) @@ -144,6 +144,16 @@ static int mxge_close(mxge_softc_t *sc); static int mxge_open(mxge_softc_t *sc); static void mxge_tick(void *arg); +#if defined(__i386__) || defined(__amd64__) +static __inline +void prefetch(void *x) +{ + __asm volatile("prefetcht0 %0" :: "m" (*(unsigned long *)x)); +} +#else +#define prefetch(x) +#endif + static int mxge_probe(device_t dev) { @@ -2471,6 +2481,8 @@ mxge_rx_done_big(struct mxge_slice_state old_map = rx->info[idx].map; bus_dmamap_sync(rx->dmat, old_map, BUS_DMASYNC_POSTREAD); bus_dmamap_unload(rx->dmat, old_map); + prefetch(rx->info[(idx + 2) & rx->mask].m); + prefetch(rx->info[(idx + 3) & rx->mask].m); /* swap the bus_dmamap_t's */ rx->info[idx].map = rx->extra_map; @@ -2520,6 +2532,9 @@ mxge_rx_done_small(struct mxge_slice_sta rx = &ss->rx_small; idx = rx->cnt & rx->mask; rx->cnt++; + prefetch(rx->info[(idx + 2) & rx->mask].m); + prefetch(rx->info[(idx + 3) & rx->mask].m); + /* save a pointer to the received mbuf */ m = rx->info[idx].m; /* try to replace the received mbuf */ @@ -2613,6 +2628,9 @@ mxge_tx_done(struct mxge_slice_state *ss while (tx->pkt_done != mcp_idx) { idx = tx->done & tx->mask; tx->done++; + prefetch(tx->info[(idx + 2) & tx->mask].m); + prefetch(tx->info[(idx + 3) & tx->mask].m); + m = tx->info[idx].m; /* mbuf and DMA map only attached to the first segment per-mbuf */