* [Qemu-devel] [PATCH] block/nvme: optimize the performance of nvme driver based on vfio-pci
@ 2018-11-01 10:38 Li Feng
2018-11-02 6:47 ` Fam Zheng
0 siblings, 1 reply; 2+ messages in thread
From: Li Feng @ 2018-11-01 10:38 UTC (permalink / raw)
To: fengli
Cc: Li Feng, Fam Zheng, Kevin Wolf, Max Reitz,
open list:NVMe Block Driver, open list:All patches CC here
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 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>
---
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
^ permalink raw reply related [flat|nested] 2+ messages in thread
* Re: [Qemu-devel] [PATCH] block/nvme: optimize the performance of nvme driver based on vfio-pci
2018-11-01 10:38 [Qemu-devel] [PATCH] block/nvme: optimize the performance of nvme driver based on vfio-pci Li Feng
@ 2018-11-02 6:47 ` Fam Zheng
0 siblings, 0 replies; 2+ messages in thread
From: Fam Zheng @ 2018-11-02 6:47 UTC (permalink / raw)
To: Li Feng
Cc: fengli, Kevin Wolf, Max Reitz, open list:NVMe Block Driver,
open list:All patches CC here
On Thu, 11/01 18:38, Li Feng wrote:
> 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 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>
> ---
> 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
>
Nice! Thanks. I've queued the patch.
Fam
^ permalink raw reply [flat|nested] 2+ messages in thread
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2018-11-02 6:47 ` Fam Zheng
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