Re: [Qemu-devel] [PATCH 1/3] block: ignore flush requests when storage is clean

2016-06-29 Thread Denis V. Lunev
On 06/29/2016 10:36 AM, Paolo Bonzini wrote: On 28/06/2016 23:01, Paolo Bonzini wrote: On 24/06/2016 17:06, Denis V. Lunev wrote: From: Evgeny Yakovlev Some guests (win2008 server for example) do a lot of unnecessary flushing when underlying media has not changed. This adds additional overh

Re: [Qemu-devel] [PATCH 1/3] block: ignore flush requests when storage is clean

2016-06-29 Thread Paolo Bonzini
On 28/06/2016 23:01, Paolo Bonzini wrote: > > > On 24/06/2016 17:06, Denis V. Lunev wrote: >> From: Evgeny Yakovlev >> >> Some guests (win2008 server for example) do a lot of unnecessary >> flushing when underlying media has not changed. This adds additional >> overhead on host when calling fs

Re: [Qemu-devel] [PATCH 1/3] block: ignore flush requests when storage is clean

2016-06-28 Thread Paolo Bonzini
On 24/06/2016 17:06, Denis V. Lunev wrote: > From: Evgeny Yakovlev > > Some guests (win2008 server for example) do a lot of unnecessary > flushing when underlying media has not changed. This adds additional > overhead on host when calling fsync/fdatasync. > > This change introduces a dirty fla

Re: [Qemu-devel] [PATCH 1/3] block: ignore flush requests when storage is clean

2016-06-24 Thread Evgeny Yakovlev
On 24.06.2016 18:31, Eric Blake wrote: On 06/24/2016 09:06 AM, Denis V. Lunev wrote: From: Evgeny Yakovlev Some guests (win2008 server for example) do a lot of unnecessary flushing when underlying media has not changed. This adds additional overhead on host when calling fsync/fdatasync. This

Re: [Qemu-devel] [PATCH 1/3] block: ignore flush requests when storage is clean

2016-06-24 Thread Eric Blake
On 06/24/2016 09:06 AM, Denis V. Lunev wrote: > From: Evgeny Yakovlev > > Some guests (win2008 server for example) do a lot of unnecessary > flushing when underlying media has not changed. This adds additional > overhead on host when calling fsync/fdatasync. > > This change introduces a dirty fl

[Qemu-devel] [PATCH 1/3] block: ignore flush requests when storage is clean

2016-06-24 Thread Denis V. Lunev
From: Evgeny Yakovlev Some guests (win2008 server for example) do a lot of unnecessary flushing when underlying media has not changed. This adds additional overhead on host when calling fsync/fdatasync. This change introduces a dirty flag in BlockDriverState which is set in bdrv_set_dirty and is