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| author | Li Feng <lifeng1519@gmail.com> | 2018-11-01 18:38:07 +0800 |
|---|---|---|
| committer | Fam Zheng <fam@euphon.net> | 2019-01-09 09:38:34 +0800 |
| commit | 2916405a11d3119cfa367ea73d66e22ea8118382 (patch) | |
| tree | 7a8b3d13cd48bbafde0c95b9bbbff196428f3ded /block/nvme.c | |
| parent | 147923b1a901a0370f83a0f4c58ec1baffef22f0 (diff) | |
| download | qemu-2916405a11d3119cfa367ea73d66e22ea8118382.zip qemu-2916405a11d3119cfa367ea73d66e22ea8118382.tar.gz qemu-2916405a11d3119cfa367ea73d66e22ea8118382.tar.bz2 | |
block/nvme: optimize the performance of nvme driver based on vfio-pci
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 <lifeng1519@gmail.com>
Message-Id: <20181101103807.25862-1-lifeng1519@gmail.com>
Signed-off-by: Fam Zheng <famz@redhat.com>
Diffstat (limited to 'block/nvme.c')
| -rw-r--r-- | block/nvme.c | 16 |
1 files changed, 6 insertions, 10 deletions
diff --git a/block/nvme.c b/block/nvme.c index 2929403..982097b 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); |