From owner-svn-src-all@freebsd.org Wed May 18 03:28:52 2016 Return-Path: Delivered-To: svn-src-all@mailman.ysv.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:1900:2254:206a::19:1]) by mailman.ysv.freebsd.org (Postfix) with ESMTP id 70FA8B3F252; Wed, 18 May 2016 03:28:52 +0000 (UTC) (envelope-from sephe@FreeBSD.org) Received: from repo.freebsd.org (repo.freebsd.org [IPv6:2610:1c1:1:6068::e6a:0]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client did not present a certificate) by mx1.freebsd.org (Postfix) with ESMTPS id 27CE811E9; Wed, 18 May 2016 03:28:52 +0000 (UTC) (envelope-from sephe@FreeBSD.org) Received: from repo.freebsd.org ([127.0.1.37]) by repo.freebsd.org (8.15.2/8.15.2) with ESMTP id u4I3Sp4l003632; Wed, 18 May 2016 03:28:51 GMT (envelope-from sephe@FreeBSD.org) Received: (from sephe@localhost) by repo.freebsd.org (8.15.2/8.15.2/Submit) id u4I3SpND003631; Wed, 18 May 2016 03:28:51 GMT (envelope-from sephe@FreeBSD.org) Message-Id: <201605180328.u4I3SpND003631@repo.freebsd.org> X-Authentication-Warning: repo.freebsd.org: sephe set sender to sephe@FreeBSD.org using -f From: Sepherosa Ziehau Date: Wed, 18 May 2016 03:28:51 +0000 (UTC) To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: svn commit: r300105 - head/sys/dev/hyperv/vmbus X-SVN-Group: head MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-BeenThere: svn-src-all@freebsd.org X-Mailman-Version: 2.1.22 Precedence: list List-Id: "SVN commit messages for the entire src tree \(except for " user" and " projects" \)" List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 18 May 2016 03:28:52 -0000 Author: sephe Date: Wed May 18 03:28:51 2016 New Revision: 300105 URL: https://svnweb.freebsd.org/changeset/base/300105 Log: hyperv/vmbus: Use atomic swap and flsl to process event flags Greatly reduce the locked instructions and reduce number of inner loops. MFC after: 1 week Sponsored by: Microsoft OSTC Differential Revision: https://reviews.freebsd.org/D6404 Modified: head/sys/dev/hyperv/vmbus/hv_connection.c Modified: head/sys/dev/hyperv/vmbus/hv_connection.c ============================================================================== --- head/sys/dev/hyperv/vmbus/hv_connection.c Wed May 18 03:23:07 2016 (r300104) +++ head/sys/dev/hyperv/vmbus/hv_connection.c Wed May 18 03:28:51 2016 (r300105) @@ -332,32 +332,32 @@ hv_vmbus_on_events(int cpu) */ for (f = 0; f < flag_cnt; f++) { uint32_t rel_id_base; + unsigned long flags; int bit; if (intr_flags[f] == 0) continue; + flags = atomic_swap_long(&intr_flags[f], 0); rel_id_base = f << HV_CHANNEL_ULONG_SHIFT; - for (bit = 0; bit < HV_CHANNEL_ULONG_LEN; bit++) { - if (atomic_testandclear_long(&intr_flags[f], bit)) { - struct hv_vmbus_channel *channel; - uint32_t rel_id; - - rel_id = rel_id_base + bit; - channel = - hv_vmbus_g_connection.channels[rel_id]; - - /* if channel is closed or closing */ - if (channel == NULL || channel->rxq == NULL) - continue; - - if (channel->batched_reading) { - hv_ring_buffer_read_begin( - &channel->inbound); - } - taskqueue_enqueue(channel->rxq, - &channel->channel_task); - } + + while ((bit = ffsl(flags)) != 0) { + struct hv_vmbus_channel *channel; + uint32_t rel_id; + + --bit; /* NOTE: ffsl is 1-based */ + flags &= ~(1UL << bit); + + rel_id = rel_id_base + bit; + channel = hv_vmbus_g_connection.channels[rel_id]; + + /* if channel is closed or closing */ + if (channel == NULL || channel->rxq == NULL) + continue; + + if (channel->batched_reading) + hv_ring_buffer_read_begin(&channel->inbound); + taskqueue_enqueue(channel->rxq, &channel->channel_task); } } }