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Groups > linux.kernel > #1211364 > unrolled thread
| Started by | Paolo Bonzini <pbonzini@redhat.com> |
|---|---|
| First post | 2015-08-22 01:00 +0200 |
| Last post | 2015-09-07 18:20 +0200 |
| Articles | 2 — 1 participant |
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[PATCH] virtio-blk: use VIRTIO_BLK_F_WCE and VIRTIO_BLK_F_CONFIG_WCE in virtio1 Paolo Bonzini <pbonzini@redhat.com> - 2015-08-22 01:00 +0200
Re: [PATCH] virtio-blk: use VIRTIO_BLK_F_WCE and VIRTIO_BLK_F_CONFIG_WCE in virtio1 Paolo Bonzini <pbonzini@redhat.com> - 2015-09-07 18:20 +0200
| From | Paolo Bonzini <pbonzini@redhat.com> |
|---|---|
| Date | 2015-08-22 01:00 +0200 |
| Subject | [PATCH] virtio-blk: use VIRTIO_BLK_F_WCE and VIRTIO_BLK_F_CONFIG_WCE in virtio1 |
| Message-ID | <q03rZ-HK-21@gated-at.bofh.it> |
VIRTIO_BLK_F_CONFIG_WCE is important in order to achieve good performance
(up to 2x, though more realistically +30-40%) in latency-bound workloads.
However, it was removed by mistake together with VIRTIO_BLK_F_FLUSH.
It will be restored in the next revision of the virtio 1.0 standard, so
do the same in Linux.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
drivers/block/virtio_blk.c | 5 ++---
1 file changed, 2 insertions(+), 3 deletions(-)
diff --git a/drivers/block/virtio_blk.c b/drivers/block/virtio_blk.c
index d4d05f064d39..ea2c17c66dfb 100644
--- a/drivers/block/virtio_blk.c
+++ b/drivers/block/virtio_blk.c
@@ -478,8 +478,7 @@ static int virtblk_get_cache_mode(struct virtio_device *vdev)
struct virtio_blk_config, wce,
&writeback);
if (err)
- writeback = virtio_has_feature(vdev, VIRTIO_BLK_F_WCE) ||
- virtio_has_feature(vdev, VIRTIO_F_VERSION_1);
+ writeback = virtio_has_feature(vdev, VIRTIO_BLK_F_WCE);
return writeback;
}
@@ -840,7 +839,7 @@ static unsigned int features_legacy[] = {
static unsigned int features[] = {
VIRTIO_BLK_F_SEG_MAX, VIRTIO_BLK_F_SIZE_MAX, VIRTIO_BLK_F_GEOMETRY,
VIRTIO_BLK_F_RO, VIRTIO_BLK_F_BLK_SIZE,
- VIRTIO_BLK_F_TOPOLOGY,
+ VIRTIO_BLK_F_WCE, VIRTIO_BLK_F_TOPOLOGY, VIRTIO_BLK_F_CONFIG_WCE,
VIRTIO_BLK_F_MQ,
};
--
2.4.3
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| From | Paolo Bonzini <pbonzini@redhat.com> |
|---|---|
| Date | 2015-09-07 18:20 +0200 |
| Subject | Re: [PATCH] virtio-blk: use VIRTIO_BLK_F_WCE and VIRTIO_BLK_F_CONFIG_WCE in virtio1 |
| Message-ID | <q67jb-2cI-17@gated-at.bofh.it> |
| In reply to | #1211364 |
On 22/08/2015 00:53, Paolo Bonzini wrote:
> VIRTIO_BLK_F_CONFIG_WCE is important in order to achieve good performance
> (up to 2x, though more realistically +30-40%) in latency-bound workloads.
> However, it was removed by mistake together with VIRTIO_BLK_F_FLUSH.
>
> It will be restored in the next revision of the virtio 1.0 standard, so
> do the same in Linux.
>
> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
> ---
> drivers/block/virtio_blk.c | 5 ++---
> 1 file changed, 2 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/block/virtio_blk.c b/drivers/block/virtio_blk.c
> index d4d05f064d39..ea2c17c66dfb 100644
> --- a/drivers/block/virtio_blk.c
> +++ b/drivers/block/virtio_blk.c
> @@ -478,8 +478,7 @@ static int virtblk_get_cache_mode(struct virtio_device *vdev)
> struct virtio_blk_config, wce,
> &writeback);
> if (err)
> - writeback = virtio_has_feature(vdev, VIRTIO_BLK_F_WCE) ||
> - virtio_has_feature(vdev, VIRTIO_F_VERSION_1);
> + writeback = virtio_has_feature(vdev, VIRTIO_BLK_F_WCE);
>
> return writeback;
> }
> @@ -840,7 +839,7 @@ static unsigned int features_legacy[] = {
> static unsigned int features[] = {
> VIRTIO_BLK_F_SEG_MAX, VIRTIO_BLK_F_SIZE_MAX, VIRTIO_BLK_F_GEOMETRY,
> VIRTIO_BLK_F_RO, VIRTIO_BLK_F_BLK_SIZE,
> - VIRTIO_BLK_F_TOPOLOGY,
> + VIRTIO_BLK_F_WCE, VIRTIO_BLK_F_TOPOLOGY, VIRTIO_BLK_F_CONFIG_WCE,
> VIRTIO_BLK_F_MQ,
> };
>
>
Ping?
Paolo
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