From: Kevin Wolf <kwolf@redhat.com>
To: dlaor@redhat.com
Cc: qemu-devel@nongnu.org
Subject: Re: [Qemu-devel] [PATCH 0/3] qcow2: Write complete sectors
Date: Tue, 16 Jun 2009 12:15:02 +0200 [thread overview]
Message-ID: <4A3770A6.9000904@redhat.com> (raw)
In-Reply-To: <4A376DEB.4070008@redhat.com>
Dor Laor schrieb:
> On 06/16/2009 12:31 PM, Kevin Wolf wrote:
>> Once upon a time, there was a bdrv_pwrite that actually wrote single bytes to
>> the file... However, today it is emulated by a read-modify-write cycle which
>> aligns the request to sector size. This is slow. And we don't need it: qcow2
>> often has the complete sector in memory, we don't need to read it from the disk
>> again.
>>
>> These patches change the writes to L1 tables, L2 tables and refcount blocks to
>> write complete sectors instead of single entries.
>>
>> This series depends on the qcow2 split to apply cleanly.
>>
>>
>
> If it's not an RFC, you better prepare a git tree for Anthony to pull from
I can do that, but the patches need to be on the list anyway.
> and described how did you test it. Maybe committing the qemu-io scripts
> would also be a move in the right direction.
Anthony is promising for a while now that he will push his tests to the
tree. Once he has done so, I'll consider integrating my script.
Kevin
next prev parent reply other threads:[~2009-06-16 10:16 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-06-16 9:31 [Qemu-devel] [PATCH 0/3] qcow2: Write complete sectors Kevin Wolf
2009-06-16 9:31 ` [Qemu-devel] [PATCH 1/3] l2_allocate: " Kevin Wolf
2009-06-16 9:31 ` [Qemu-devel] [PATCH 2/3] alloc_cluster_link_l2: " Kevin Wolf
2009-06-16 9:31 ` [Qemu-devel] [PATCH 3/3] update_refcount: " Kevin Wolf
2009-06-16 10:03 ` [Qemu-devel] [PATCH 0/3] qcow2: " Dor Laor
2009-06-16 10:15 ` Kevin Wolf [this message]
2009-06-16 10:06 ` Avi Kivity
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