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Re: [Qemu-devel] [PATCH 08/10] virtio: cache used_idx in a VirtQueue fie
From: |
Cornelia Huck |
Subject: |
Re: [Qemu-devel] [PATCH 08/10] virtio: cache used_idx in a VirtQueue field |
Date: |
Tue, 19 Jan 2016 17:11:29 +0100 |
On Fri, 15 Jan 2016 13:41:56 +0100
Paolo Bonzini <address@hidden> wrote:
> From: Vincenzo Maffione <address@hidden>
>
> Accessing used_idx in the VQ requires an expensive access to
> guest physical memory. Before this patch, 3 accesses are normally
> done for each pop/push/notify call. However, since the used_idx is
> only written by us, we can track it in our internal data structure.
>
> Signed-off-by: Vincenzo Maffione <address@hidden>
> Message-Id: <address@hidden>
> Signed-off-by: Paolo Bonzini <address@hidden>
> ---
> hw/virtio/virtio.c | 12 +++++++++---
> 1 file changed, 9 insertions(+), 3 deletions(-)
Reviewed-by: Cornelia Huck <address@hidden>
- Re: [Qemu-devel] [PATCH 01/10] virtio: move VirtQueueElement at the beginning of the structs, (continued)
- [Qemu-devel] [PATCH 03/10] virtio: introduce qemu_get/put_virtqueue_element, Paolo Bonzini, 2016/01/15
- [Qemu-devel] [PATCH 05/10] virtio: slim down allocation of VirtQueueElements, Paolo Bonzini, 2016/01/15
- [Qemu-devel] [PATCH 06/10] vring: slim down allocation of VirtQueueElements, Paolo Bonzini, 2016/01/15
- [Qemu-devel] [PATCH 04/10] virtio: introduce virtqueue_alloc_element, Paolo Bonzini, 2016/01/15
- [Qemu-devel] [PATCH 08/10] virtio: cache used_idx in a VirtQueue field, Paolo Bonzini, 2016/01/15
- Re: [Qemu-devel] [PATCH 08/10] virtio: cache used_idx in a VirtQueue field,
Cornelia Huck <=
- [Qemu-devel] [PATCH 02/10] virtio: move allocation to virtqueue_pop/vring_pop, Paolo Bonzini, 2016/01/15
- [Qemu-devel] [PATCH 07/10] virtio: combine the read of a descriptor, Paolo Bonzini, 2016/01/15
- [Qemu-devel] [PATCH 10/10] virtio: combine write of an entry into used ring, Paolo Bonzini, 2016/01/15
- [Qemu-devel] [PATCH 09/10] virtio: read avail_idx from VQ only when necessary, Paolo Bonzini, 2016/01/15