From: "Chen, Kenneth W" <kenneth.w.chen@intel.com>
To: "'Andrew Morton'" <akpm@osdl.org>
Cc: <linux-kernel@vger.kernel.org>, <axboe@suse.de>
Subject: RE: Direct io on block device has performance regression on 2.6.x kernel
Date: Thu, 10 Mar 2005 13:42:12 -0800 [thread overview]
Message-ID: <200503102142.j2ALgCg04691@unix-os.sc.intel.com> (raw)
In-Reply-To: <20050310123043.69e5fd48.akpm@osdl.org>
Andrew Morton wrote on Thursday, March 10, 2005 12:31 PM
> > > Fine-grained alignment is probably too hard, and it should fall back to
> > > __blockdev_direct_IO().
> > >
> > > Does it do the right thing with a request which is non-page-aligned, but
> > > 512-byte aligned?
> > >
> > > readv and writev?
> > >
> >
> > That's why direct_io_worker() is slower. It does everything and handles
> > every possible usage scenarios out there. I hope making the function fatter
> > is not in the plan.
>
> We just cannot make a change like this if it does not support readv and
> writev well, and if it does not support down-to-512-byte size and
> alignment. It will break applications.
I must misread your mail. Yes it does support 512-byte size and alignment.
Let me work on the readv/writev support (unless someone beat me to it).
- Ken
next prev parent reply other threads:[~2005-03-10 22:02 UTC|newest]
Thread overview: 29+ messages / expand[flat|nested] mbox.gz Atom feed top
2005-03-09 1:39 Direct io on block device has performance regression on 2.6.x kernel Chen, Kenneth W
2005-03-09 6:27 ` Andrew Morton
2005-03-09 17:21 ` Chen, Kenneth W
2005-03-09 20:04 ` Andrew Morton
2005-03-09 21:59 ` Chen, Kenneth W
2005-03-09 22:44 ` Andrew Morton
2005-03-10 1:11 ` Chen, Kenneth W
2005-03-10 1:33 ` Andrew Morton
2005-03-10 1:44 ` Chen, Kenneth W
2005-03-10 2:25 ` Andrew Morton
2005-03-10 3:47 ` Chen, Kenneth W
2005-03-10 4:04 ` David Lang
2005-03-10 4:10 ` Andrew Morton
2005-03-10 4:15 ` Direct io on block device has performance regression on 2.6.xkernel David Lang
2005-03-10 4:09 ` Direct io on block device has performance regression on 2.6.x kernel Andrew Morton
2005-03-10 18:31 ` Chen, Kenneth W
2005-03-10 20:30 ` Andrew Morton
2005-03-10 21:42 ` Chen, Kenneth W [this message]
2005-03-10 22:01 ` Andrew Morton
2005-03-10 4:28 ` Andrew Vasquez
-- strict thread matches above, loose matches on Subject: below --
2005-03-09 1:53 Chen, Kenneth W
2005-03-09 22:18 Chen, Kenneth W
2005-03-09 23:23 ` Andi Kleen
2005-03-09 23:52 ` Jesse Barnes
2005-03-09 23:52 ` Jesse Barnes
2005-03-10 1:00 ` Chen, Kenneth W
2005-03-10 0:57 ` Chen, Kenneth W
2005-03-10 1:24 Chen, Kenneth W
2005-03-10 2:04 Chen, Kenneth W
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