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Re: [Qemu-devel] [RFC PATCH] block: optimize zero writes with bdrv_write
From: |
Fam Zheng |
Subject: |
Re: [Qemu-devel] [RFC PATCH] block: optimize zero writes with bdrv_write_zeroes |
Date: |
Sun, 23 Feb 2014 00:45:12 +0800 |
User-agent: |
Mutt/1.5.22 (2013-10-16) |
On Sat, 02/22 14:00, Peter Lieven wrote:
> this patch tries to optimize zero write requests
> by automatically using bdrv_write_zeroes if it is
> supported by the format.
>
> i know that there is a lot of potential for discussion, but i would
> like to know what the others think.
>
> this should significantly speed up file system initialization and
> should speed zero write test used to test backend storage performance.
>
> the difference can simply be tested by e.g.
>
> dd if=/dev/zero of=/dev/vdX bs=1M
>
> Signed-off-by: Peter Lieven <address@hidden>
> ---
With this patch, is is still possible to actually do zero fill? Prefill is
usually writing zeroes too, but according to the semantic, bdrv_write_zeroes
may just set L2 entry flag without allocating clusters, which won't satisfy
that.
Thanks,
Fam
- [Qemu-devel] [RFC PATCH] block: optimize zero writes with bdrv_write_zeroes, Peter Lieven, 2014/02/22
- Re: [Qemu-devel] [RFC PATCH] block: optimize zero writes with bdrv_write_zeroes,
Fam Zheng <=
- Re: [Qemu-devel] [RFC PATCH] block: optimize zero writes with bdrv_write_zeroes, Peter Lieven, 2014/02/23
- Re: [Qemu-devel] [RFC PATCH] block: optimize zero writes with bdrv_write_zeroes, Fam Zheng, 2014/02/23
- Re: [Qemu-devel] [RFC PATCH] block: optimize zero writes with bdrv_write_zeroes, Paolo Bonzini, 2014/02/24
- Re: [Qemu-devel] [RFC PATCH] block: optimize zero writes with bdrv_write_zeroes, Fam Zheng, 2014/02/24
- Re: [Qemu-devel] [RFC PATCH] block: optimize zero writes with bdrv_write_zeroes, Paolo Bonzini, 2014/02/24
- Re: [Qemu-devel] [RFC PATCH] block: optimize zero writes with bdrv_write_zeroes, Fam Zheng, 2014/02/24
- Re: [Qemu-devel] [RFC PATCH] block: optimize zero writes with bdrv_write_zeroes, Kevin Wolf, 2014/02/24
- Re: [Qemu-devel] [RFC PATCH] block: optimize zero writes with bdrv_write_zeroes, Paolo Bonzini, 2014/02/24
- Re: [Qemu-devel] [RFC PATCH] block: optimize zero writes with bdrv_write_zeroes, Kevin Wolf, 2014/02/24
Re: [Qemu-devel] [RFC PATCH] block: optimize zero writes with bdrv_write_zeroes, Kevin Wolf, 2014/02/24