On Thu, Nov 16, 2017 at 06:00:54PM +, Richard W.M. Jones wrote:
> On Thu, Nov 16, 2017 at 05:30:48PM +, Stefan Hajnoczi wrote:
> > On Thu, Nov 16, 2017 at 3:10 PM, Richard W.M. Jones
> > wrote:
> > > Both local filesystems, but on different SATA devices.
> >
> > Okay. I'm curious what t
On Thu, Nov 16, 2017 at 05:30:48PM +, Stefan Hajnoczi wrote:
> On Thu, Nov 16, 2017 at 3:10 PM, Richard W.M. Jones wrote:
> > Both local filesystems, but on different SATA devices.
>
> Okay. I'm curious what the strace -f output looks like (only the
> preadv(2)/pwritev(2) syscalls are intere
On Thu, Nov 16, 2017 at 3:10 PM, Richard W.M. Jones wrote:
> On Thu, Nov 16, 2017 at 02:47:46PM +, Stefan Hajnoczi wrote:
>> The threads you observed are the thread pool that performs
>> preadv(2)/pwritev(2) syscalls. The Linux AIO API could be used instead
>> and does not use threads for rea
On Thu, Nov 16, 2017 at 3:12 PM, Richard W.M. Jones wrote:
> On Thu, Nov 16, 2017 at 03:51:29PM +0100, Peter Lieven wrote:
>> Afaik all writes to the same QCOW2 serialize because of the s->lock that
>> is held during the write. So its not suprising that there is no benefit from
>> mutliple threads
On Thu, Nov 16, 2017 at 03:51:29PM +0100, Peter Lieven wrote:
> Afaik all writes to the same QCOW2 serialize because of the s->lock that
> is held during the write. So its not suprising that there is no benefit from
> mutliple threads as long as reading from the RAW file involves no delay.
> Which
On Thu, Nov 16, 2017 at 02:47:46PM +, Stefan Hajnoczi wrote:
> The threads you observed are the thread pool that performs
> preadv(2)/pwritev(2) syscalls. The Linux AIO API could be used instead
> and does not use threads for read and write operations.
I guess if I used AIO then I wouldn't ge
Am 16.11.2017 um 15:47 schrieb Stefan Hajnoczi:
On Wed, Nov 15, 2017 at 11:52:46AM +, Richard W.M. Jones wrote:
[CC to qemu-devel since I'm obviously doing something wrong here,
I'm just not sure what.]
I was getting ready to add multiple threads to ‘qemu-img convert’ (the
longest part of v
On Wed, Nov 15, 2017 at 11:52:46AM +, Richard W.M. Jones wrote:
> [CC to qemu-devel since I'm obviously doing something wrong here,
> I'm just not sure what.]
>
> I was getting ready to add multiple threads to ‘qemu-img convert’ (the
> longest part of v2v conversions) when I noticed that it ha
[CC to qemu-devel since I'm obviously doing something wrong here,
I'm just not sure what.]
I was getting ready to add multiple threads to ‘qemu-img convert’ (the
longest part of v2v conversions) when I noticed that it had them
already! (To be fair this was only added in February this year so no
w
