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Re: [Qemu-devel] [PATCH 1/4] block: add enable_write_cache flag
From: |
Christoph Hellwig |
Subject: |
Re: [Qemu-devel] [PATCH 1/4] block: add enable_write_cache flag |
Date: |
Tue, 1 Sep 2009 01:09:02 +0200 |
User-agent: |
Mutt/1.3.28i |
On Tue, Sep 01, 2009 at 01:06:46AM +0200, Christoph Hellwig wrote:
> On Mon, Aug 31, 2009 at 11:59:25PM +0100, Jamie Lokier wrote:
> > Anthony Liguori wrote:
> > > Can someone do some benchmarking with cache=writeback and fdatasync
> > > first and quantify what the real performance impact is?
> >
> > Unfortunately we can't yet quantify the impact on the hardware I care
> > about (ordinary consumer PCs with non-NCQ SATA disks), because Linux
> > hosts don't *yet* implement O_SYNC or fdatasync properly.
>
> They do if you use XFS.
And data-writeback + fdatasync also when using reiserfs. For ext3/4 you
need the patches I sent out today, for O_SYNC on everythig but XFS also
Jan Kara's patch series.
- [Qemu-devel] [PATCH 1/4] block: add enable_write_cache flag, (continued)
- [Qemu-devel] [PATCH 1/4] block: add enable_write_cache flag, Christoph Hellwig, 2009/08/31
- Re: [Qemu-devel] [PATCH 1/4] block: add enable_write_cache flag, Jamie Lokier, 2009/08/31
- Re: [Qemu-devel] [PATCH 1/4] block: add enable_write_cache flag, Anthony Liguori, 2009/08/31
- Re: [Qemu-devel] [PATCH 1/4] block: add enable_write_cache flag, Jamie Lokier, 2009/08/31
- Re: [Qemu-devel] [PATCH 1/4] block: add enable_write_cache flag, Christoph Hellwig, 2009/08/31
- Re: [Qemu-devel] [PATCH 1/4] block: add enable_write_cache flag, Jamie Lokier, 2009/08/31
- Re: [Qemu-devel] [PATCH 1/4] block: add enable_write_cache flag, Christoph Hellwig, 2009/08/31
- Re: [Qemu-devel] [PATCH 1/4] block: add enable_write_cache flag,
Christoph Hellwig <=
[Qemu-devel] [PATCH 2/4] block: use fdatasync instead of fsync, Christoph Hellwig, 2009/08/31
[Qemu-devel] [PATCH 3/4] block: add bdrv_aio_flush operation, Christoph Hellwig, 2009/08/31
[Qemu-devel] [PATCH 4/4] virtio-blk: add volatile writecache feature, Christoph Hellwig, 2009/08/31