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Re: [Qemu-devel] [PATCH v7 kernel 3/5] virtio-balloon: implementation of
From: |
Matthew Wilcox |
Subject: |
Re: [Qemu-devel] [PATCH v7 kernel 3/5] virtio-balloon: implementation of VIRTIO_BALLOON_F_CHUNK_TRANSFER |
Date: |
Thu, 9 Mar 2017 06:14:11 -0800 |
User-agent: |
Mutt/1.7.1 (2016-10-04) |
On Fri, Mar 03, 2017 at 01:40:28PM +0800, Wei Wang wrote:
> From: Liang Li <address@hidden>
> 1) allocating pages (6.5%)
> 2) sending PFNs to host (68.3%)
> 3) address translation (6.1%)
> 4) madvise (19%)
>
> This patch optimizes step 2) by transfering pages to the host in
> chunks. A chunk consists of guest physically continuous pages, and
> it is offered to the host via a base PFN (i.e. the start PFN of
> those physically continuous pages) and the size (i.e. the total
> number of the pages). A normal chunk is formated as below:
> -----------------------------------------------
> | Base (52 bit) | Size (12 bit)|
> -----------------------------------------------
> For large size chunks, an extended chunk format is used:
> -----------------------------------------------
> | Base (64 bit) |
> -----------------------------------------------
> -----------------------------------------------
> | Size (64 bit) |
> -----------------------------------------------
What's the advantage to extended chunks? IOW, why is the added complexity
of having two chunk formats worth it? You already reduced the overhead by
a factor of 4096 with normal chunks ... how often are extended chunks used
and how much more efficient are they than having several normal chunks?
- Re: [Qemu-devel] [PATCH v7 kernel 2/5] virtio-balloon: VIRTIO_BALLOON_F_CHUNK_TRANSFER, (continued)
- [Qemu-devel] [PATCH v7 kernel 1/5] virtio-balloon: rework deflate to add page to a list, Wei Wang, 2017/03/03
- [Qemu-devel] [PATCH v7 kernel 4/5] virtio-balloon: define flags and head for host request vq, Wei Wang, 2017/03/03
- [Qemu-devel] [PATCH v7 kernel 3/5] virtio-balloon: implementation of VIRTIO_BALLOON_F_CHUNK_TRANSFER, Wei Wang, 2017/03/03
- Re: [Qemu-devel] [PATCH v7 kernel 3/5] virtio-balloon: implementation of VIRTIO_BALLOON_F_CHUNK_TRANSFER,
Matthew Wilcox <=
- Re: [Qemu-devel] [PATCH v7 kernel 3/5] virtio-balloon: implementation of VIRTIO_BALLOON_F_CHUNK_TRANSFER, Wei Wang, 2017/03/10
- Re: [Qemu-devel] [PATCH v7 kernel 3/5] virtio-balloon: implementation of VIRTIO_BALLOON_F_CHUNK_TRANSFER, Michael S. Tsirkin, 2017/03/10
- Re: [Qemu-devel] [PATCH v7 kernel 3/5] virtio-balloon: implementation of VIRTIO_BALLOON_F_CHUNK_TRANSFER, Matthew Wilcox, 2017/03/10
- Re: [Qemu-devel] [PATCH v7 kernel 3/5] virtio-balloon: implementation of VIRTIO_BALLOON_F_CHUNK_TRANSFER, Michael S. Tsirkin, 2017/03/10
- Re: [Qemu-devel] [PATCH v7 kernel 3/5] virtio-balloon: implementation of VIRTIO_BALLOON_F_CHUNK_TRANSFER, Matthew Wilcox, 2017/03/10
- Re: [Qemu-devel] [PATCH v7 kernel 3/5] virtio-balloon: implementation of VIRTIO_BALLOON_F_CHUNK_TRANSFER, Michael S. Tsirkin, 2017/03/10
- Re: [Qemu-devel] [PATCH v7 kernel 3/5] virtio-balloon: implementation of VIRTIO_BALLOON_F_CHUNK_TRANSFER, Matthew Wilcox, 2017/03/10
- Re: [Qemu-devel] [PATCH v7 kernel 3/5] virtio-balloon: implementation of VIRTIO_BALLOON_F_CHUNK_TRANSFER, Michael S. Tsirkin, 2017/03/11
- Re: [Qemu-devel] [PATCH v7 kernel 3/5] virtio-balloon: implementation of VIRTIO_BALLOON_F_CHUNK_TRANSFER, Wei Wang, 2017/03/11
- Re: [Qemu-devel] [PATCH v7 kernel 3/5] virtio-balloon: implementation of VIRTIO_BALLOON_F_CHUNK_TRANSFER, Matthew Wilcox, 2017/03/11