Re: [Qemu-devel] I/O parallelism on QCOW2

2014-09-08 Thread Stefan Hajnoczi
On Fri, Sep 05, 2014 at 12:45:27PM -0400, Xingbo Wu wrote: > On Fri, Sep 5, 2014 at 6:02 AM, Stefan Hajnoczi wrote: > > > On Thu, Sep 04, 2014 at 12:32:12PM -0400, Xingbo Wu wrote: > > > After running a 16-thread sync-random-write test against qcow2, It is > > > observed that QCOW2 seems to be

Re: [Qemu-devel] I/O parallelism on QCOW2

2014-09-05 Thread Xingbo Wu
On Fri, Sep 5, 2014 at 6:02 AM, Stefan Hajnoczi wrote: > On Thu, Sep 04, 2014 at 12:32:12PM -0400, Xingbo Wu wrote: > > After running a 16-thread sync-random-write test against qcow2, It is > > observed that QCOW2 seems to be serializing all its metadata-related > writes. > > If qcow2 is desig

Re: [Qemu-devel] I/O parallelism on QCOW2

2014-09-05 Thread Stefan Hajnoczi
On Thu, Sep 04, 2014 at 12:32:12PM -0400, Xingbo Wu wrote: > After running a 16-thread sync-random-write test against qcow2, It is > observed that QCOW2 seems to be serializing all its metadata-related writes. > If qcow2 is designed to do this,* then what is the concern?* What would go > wrong i

[Qemu-devel] I/O parallelism on QCOW2

2014-09-04 Thread Xingbo Wu
Hello guys, After running a 16-thread sync-random-write test against qcow2, It is observed that QCOW2 seems to be serializing all its metadata-related writes. If qcow2 is designed to do this,* then what is the concern?* What would go wrong if this ordering is relaxed? By providing less features,