From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:60538) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1YIHTo-0001fO-4l for qemu-devel@nongnu.org; Mon, 02 Feb 2015 08:55:56 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1YIHTh-00069f-AS for qemu-devel@nongnu.org; Mon, 02 Feb 2015 08:55:56 -0500 Received: from mx-v6.kamp.de ([2a02:248:0:51::16]:46041 helo=mx01.kamp.de) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1YIHTh-00068T-0L for qemu-devel@nongnu.org; Mon, 02 Feb 2015 08:55:49 -0500 From: Peter Lieven Date: Mon, 2 Feb 2015 14:52:22 +0100 Message-Id: <1422885142-6391-6-git-send-email-pl@kamp.de> In-Reply-To: <1422885142-6391-1-git-send-email-pl@kamp.de> References: <1422885142-6391-1-git-send-email-pl@kamp.de> Subject: [Qemu-devel] [PATCH v4 5/5] virtio-blk: add a knob to disable request merging List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org Cc: kwolf@redhat.com, famz@redhat.com, benoit@irqsave.net, ming.lei@canonical.com, Peter Lieven , armbru@redhat.com, mreitz@redhat.com, stefanha@redhat.com, pbonzini@redhat.com this adds a knob to disable request merging for debugging or benchmarks if dedired. Signed-off-by: Peter Lieven --- hw/block/virtio-blk.c | 5 ++++- include/hw/virtio/virtio-blk.h | 1 + 2 files changed, 5 insertions(+), 1 deletion(-) diff --git a/hw/block/virtio-blk.c b/hw/block/virtio-blk.c index d0a01a8..8c51a29 100644 --- a/hw/block/virtio-blk.c +++ b/hw/block/virtio-blk.c @@ -531,7 +531,8 @@ void virtio_blk_handle_request(VirtIOBlockReq *req, MultiReqBuffer *mrb) /* merge would exceed maximum number of requests or IO direction * changes */ if (mrb->num_reqs > 0 && (mrb->num_reqs == VIRTIO_BLK_MAX_MERGE_REQS || - is_write != mrb->is_write)) { + is_write != mrb->is_write || + !req->dev->conf.request_merging)) { virtio_blk_submit_multireq(req->dev->blk, mrb); } @@ -950,6 +951,8 @@ static Property virtio_blk_properties[] = { #ifdef __linux__ DEFINE_PROP_BIT("scsi", VirtIOBlock, conf.scsi, 0, true), #endif + DEFINE_PROP_BIT("request-merging", VirtIOBlock, conf.request_merging, 0, + true), DEFINE_PROP_BIT("x-data-plane", VirtIOBlock, conf.data_plane, 0, false), DEFINE_PROP_END_OF_LIST(), }; diff --git a/include/hw/virtio/virtio-blk.h b/include/hw/virtio/virtio-blk.h index 2027a64..fc7d311 100644 --- a/include/hw/virtio/virtio-blk.h +++ b/include/hw/virtio/virtio-blk.h @@ -113,6 +113,7 @@ struct VirtIOBlkConf uint32_t scsi; uint32_t config_wce; uint32_t data_plane; + uint32_t request_merging; }; struct VirtIOBlockDataPlane; -- 1.9.1