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Re: [Qemu-devel] [RFC PATCH v2 00/23] qcow2: Delayed COW
From: |
Kevin Wolf |
Subject: |
Re: [Qemu-devel] [RFC PATCH v2 00/23] qcow2: Delayed COW |
Date: |
Thu, 14 Feb 2013 11:56:34 +0100 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:13.0) Gecko/20120605 Thunderbird/13.0 |
Am 14.02.2013 11:43, schrieb Stefan Hajnoczi:
> On Wed, Feb 13, 2013 at 02:21:50PM +0100, Kevin Wolf wrote:
>> iozone results with and without this series show significant difference
>> for allocating writes:
>>
>> random random
>> KB reclen write rewrite read reread read write
>>
>> base 65536 8 1727 1945 12546 12539 2449 1836
>> patch 65536 8 1934 1949 12263 12521 2463 1796
>>
>> base 1048576 256 22344 38437 105823 106135 37743 32167
>> patch 1048576 256 35989 38542 105231 105994 38301 33036
>
> I imagine the benefit is even greater for 4 KB or 8 KB blocksize?
The upper two lines are 8k block size. I suspect that the benefit would
be the greatest for misaligned 64k writes, then you have one overlapping
allocation for each issued request.
Kevin
- [Qemu-devel] [RFC PATCH v2 14/23] qcow2: Use byte granularity in qcow2_alloc_cluster_offset(), (continued)
- [Qemu-devel] [RFC PATCH v2 14/23] qcow2: Use byte granularity in qcow2_alloc_cluster_offset(), Kevin Wolf, 2013/02/13
- [Qemu-devel] [RFC PATCH v2 17/23] qcow2: Move COW and L2 update into own coroutine, Kevin Wolf, 2013/02/13
- [Qemu-devel] [RFC PATCH v2 22/23] qcow2: Move cluster gathering to a non-looping loop, Kevin Wolf, 2013/02/13
- [Qemu-devel] [RFC PATCH v2 21/23] qemu-iotests: Another concurrent multicluster allocation case, Kevin Wolf, 2013/02/13
- [Qemu-devel] [RFC PATCH v2 20/23] qcow2: Cancel COW when overwritten, Kevin Wolf, 2013/02/13
- [Qemu-devel] [RFC PATCH v2 23/23] qcow2: Gather clusters in a looping loop, Kevin Wolf, 2013/02/13
- Re: [Qemu-devel] [RFC PATCH v2 00/23] qcow2: Delayed COW, Stefan Hajnoczi, 2013/02/14
- Re: [Qemu-devel] [RFC PATCH v2 00/23] qcow2: Delayed COW,
Kevin Wolf <=
- Re: [Qemu-devel] [RFC PATCH v2 00/23] qcow2: Delayed COW, Stefan Hajnoczi, 2013/02/18