From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([209.51.188.92]:41894) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1gh33z-00022W-Gr for qemu-devel@nongnu.org; Tue, 08 Jan 2019 20:53:48 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1gh33y-0005wk-LN for qemu-devel@nongnu.org; Tue, 08 Jan 2019 20:53:47 -0500 Received: from sender2-op-o12.zoho.com.cn ([163.53.93.243]:17745 helo=sender1.zoho.com.cn) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1gh33x-0005kQ-CL for qemu-devel@nongnu.org; Tue, 08 Jan 2019 20:53:46 -0500 From: Fam Zheng Date: Wed, 9 Jan 2019 09:52:39 +0800 Message-Id: <20190109015240.2116-2-fam@euphon.net> In-Reply-To: <20190109015240.2116-1-fam@euphon.net> References: <20190109015240.2116-1-fam@euphon.net> Subject: [Qemu-devel] [PULL 1/2] block/nvme: optimize the performance of nvme driver based on vfio-pci List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org Cc: peter.maydell@linaro.org, Fam Zheng From: Li Feng When the IO size is larger than 2 pages, we move the the pointer one by one in the pagelist, this is inefficient. This is a simple benchmark result: Before: $ qemu-io -c 'write 0 1G' nvme://0000:00:04.0/1 wrote 1073741824/1073741824 bytes at offset 0 1 GiB, 1 ops; 0:00:02.41 (424.504 MiB/sec and 0.4146 ops/sec) $ qemu-io -c 'read 0 1G' nvme://0000:00:04.0/1 read 1073741824/1073741824 bytes at offset 0 1 GiB, 1 ops; 0:00:02.03 (503.055 MiB/sec and 0.4913 ops/sec) After: $ qemu-io -c 'write 0 1G' nvme://0000:00:04.0/1 wrote 1073741824/1073741824 bytes at offset 0 1 GiB, 1 ops; 0:00:02.17 (471.517 MiB/sec and 0.4605 ops/sec) $ qemu-io -c 'read 0 1G' nvme://0000:00:04.0/1 read 1073741824/1073741824 bytes at offset 0 1 GiB, 1 ops; 0:00:01.94 (526.770 MiB/sec and 0.5144 ops/sec) Signed-off-by: Li Feng Message-Id: <20181101103807.25862-1-lifeng1519@gmail.com> Signed-off-by: Fam Zheng --- block/nvme.c | 16 ++++++---------- 1 file changed, 6 insertions(+), 10 deletions(-) diff --git a/block/nvme.c b/block/nvme.c index 29294038fc..982097b5b1 100644 --- a/block/nvme.c +++ b/block/nvme.c @@ -837,7 +837,7 @@ try_map: } for (j = 0; j < qiov->iov[i].iov_len / s->page_size; j++) { - pagelist[entries++] = iova + j * s->page_size; + pagelist[entries++] = cpu_to_le64(iova + j * s->page_size); } trace_nvme_cmd_map_qiov_iov(s, i, qiov->iov[i].iov_base, qiov->iov[i].iov_len / s->page_size); @@ -850,20 +850,16 @@ try_map: case 0: abort(); case 1: - cmd->prp1 = cpu_to_le64(pagelist[0]); + cmd->prp1 = pagelist[0]; cmd->prp2 = 0; break; case 2: - cmd->prp1 = cpu_to_le64(pagelist[0]); - cmd->prp2 = cpu_to_le64(pagelist[1]);; + cmd->prp1 = pagelist[0]; + cmd->prp2 = pagelist[1]; break; default: - cmd->prp1 = cpu_to_le64(pagelist[0]); - cmd->prp2 = cpu_to_le64(req->prp_list_iova); - for (i = 0; i < entries - 1; ++i) { - pagelist[i] = cpu_to_le64(pagelist[i + 1]); - } - pagelist[entries - 1] = 0; + cmd->prp1 = pagelist[0]; + cmd->prp2 = cpu_to_le64(req->prp_list_iova + sizeof(uint64_t)); break; } trace_nvme_cmd_map_qiov(s, cmd, req, qiov, entries); -- 2.11.0