On Thu, Jun 16, 2011 at 9:10 AM, Dmitry Konishchev wrote:
> On Wed, Jun 15, 2011 at 5:57 PM, Stefan Hajnoczi wrote:
>> Anyway, bdrv_getlength() will return the total_sectors value instead
>> of calling into raw-posix.c .bdrv_getlength(). That's why it should
>> be cheap.
>
> Yeah, I see it now a
On Wed, Jun 15, 2011 at 5:57 PM, Stefan Hajnoczi wrote:
> Anyway, bdrv_getlength() will return the total_sectors value instead
> of calling into raw-posix.c .bdrv_getlength(). That's why it should
> be cheap.
Yeah, I see it now after a closer look in the drivers code. It looks
like I get this 9%
2011/6/15 Dmitry Konishchev :
> On Wed, Jun 15, 2011 at 5:33 PM, Stefan Hajnoczi wrote:
>> "disable caching"?
>
> Image geometry caching. I meant If I call bdrv_get_geometry() every
> time I need image geometry instead of obtaining it from bs_geometry
> variable.
Haha, sorry. Too much caching: -
On Wed, Jun 15, 2011 at 5:33 PM, Stefan Hajnoczi wrote:
> "disable caching"?
Image geometry caching. I meant If I call bdrv_get_geometry() every
time I need image geometry instead of obtaining it from bs_geometry
variable.
--
Дмитрий Конищев (Dmitry Konishchev)
mailto:konishc...@gmail.com
On Wed, Jun 15, 2011 at 2:14 PM, Dmitry Konishchev wrote:
> On Wed, Jun 15, 2011 at 4:02 PM, Stefan Hajnoczi wrote:
>> We need to fully understand performance before applying optimizations
>> on top. Otherwise it is possible to paper over a problem while
>> leaving the root cause unsolved. Avoi
On Wed, Jun 15, 2011 at 4:02 PM, Stefan Hajnoczi wrote:
> We need to fully understand performance before applying optimizations
> on top. Otherwise it is possible to paper over a problem while
> leaving the root cause unsolved. Avoiding lseek(2) is very important,
> not just for qemu-img but als
On Wed, Jun 15, 2011 at 10:50 AM, Dmitry Konishchev
wrote:
> On Wed, Jun 15, 2011 at 12:39 PM, Stefan Hajnoczi wrote:
>> Why is bdrv_get_geometry() slow?
>
> Mmm.. Frankly, I haven't looked so deep, but it is going to be slow at
> least for raw images due to using lseek().
We need to fully under
This patch optimizes 'qemu-img convert' operation for volumes which are
almost fully unallocated. Here are the results of simple tests:
We have a snapshot of a volume:
$ qemu-img info snapshot.qcow2
image: snapshot.qcow2
file format: qcow2
virtual size: 5.0G (5372805120 bytes)
disk size: 4.0G
clus
On Wed, Jun 15, 2011 at 12:39 PM, Stefan Hajnoczi wrote:
> Why is bdrv_get_geometry() slow?
Mmm.. Frankly, I haven't looked so deep, but it is going to be slow at
least for raw images due to using lseek().
--
Dmitry Konishchev
mailto:konishc...@gmail.com
On Wed, Jun 15, 2011 at 8:38 AM, Dmitry Konishchev wrote:
> On Tue, Jun 14, 2011 at 7:58 PM, Stefan Hajnoczi wrote:
>> Yes, please.
>
> OK, I'll do it as soon I'll find time for it.
>
>
> On Tue, Jun 14, 2011 at 7:58 PM, Stefan Hajnoczi wrote:
>> For image files the block layer should be caching
On Tue, Jun 14, 2011 at 7:58 PM, Stefan Hajnoczi wrote:
> Yes, please.
OK, I'll do it as soon I'll find time for it.
On Tue, Jun 14, 2011 at 7:58 PM, Stefan Hajnoczi wrote:
> For image files the block layer should be caching the device capacity (size)
> anyway, so you probably don't need to al
On Tue, Jun 14, 2011 at 8:43 AM, Dmitry Konishchev wrote:
> On Mon, Jun 13, 2011 at 1:13 PM, Dmitry Konishchev
> wrote:
>> I haven't done this because in this case I have to pass too lot of
>> local variables to this function. Just not sure that it'll look
>> better. But if you mind I surely can
On Mon, Jun 13, 2011 at 1:13 PM, Dmitry Konishchev wrote:
> I haven't done this because in this case I have to pass too lot of
> local variables to this function. Just not sure that it'll look
> better. But if you mind I surely can do this.
Should I?
--
Dmitry Konishchev
mailto:konishc...@gmail.
On Mon, Jun 13, 2011 at 12:26 PM, Stefan Hajnoczi wrote:
> The optimization is to check allocation metadata instead of
> unconditionally reading and then checking for all zeroes?
Yeah, exactly.
On Mon, Jun 13, 2011 at 12:26 PM, Stefan Hajnoczi wrote:
> Why introduce a new constant instead of usi
On Wed, Jun 08, 2011 at 06:50:25PM +0400, Dmitry Konishchev wrote:
> This patch optimizes 'qemu-img convert' operation for volumes which are
> almost fully unallocated. Here are the results of simple tests:
The optimization is to check allocation metadata instead of
unconditionally reading and the
This patch optimizes 'qemu-img convert' operation for volumes which are
almost fully unallocated. Here are the results of simple tests:
We have a snapshot of a volume:
$ qemu-img info snapshot.qcow2
image: snapshot.qcow2
file format: qcow2
virtual size: 5.0G (5372805120 bytes)
disk size: 4.0G
clus
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