On Wed, Nov 21, 2012 at 03:51:03PM +0800, Jaegeuk Hanse wrote:
> On 11/20/2012 10:58 PM, Fengguang Wu wrote:
> >On Tue, Nov 20, 2012 at 10:34:11AM -0300, Claudio Freire wrote:
> >>On Tue, Nov 20, 2012 at 5:04 AM, Fengguang Wu
> >>wrote:
> >>>Yes. The kernel readahead code by design will outperfor
On 11/20/2012 10:58 PM, Fengguang Wu wrote:
On Tue, Nov 20, 2012 at 10:34:11AM -0300, Claudio Freire wrote:
On Tue, Nov 20, 2012 at 5:04 AM, Fengguang Wu wrote:
Yes. The kernel readahead code by design will outperform simple
fadvise in the case of clustered random reads. Imagine the access
pat
On Wed, Nov 21, 2012 at 02:51:41PM +0800, Jaegeuk Hanse wrote:
> On 11/20/2012 11:15 PM, Fengguang Wu wrote:
> >On Tue, Nov 20, 2012 at 10:11:54PM +0800, Jaegeuk Hanse wrote:
> >>On 11/20/2012 04:04 PM, Fengguang Wu wrote:
> >>>Hi Claudio,
> >>>
> >>>Thanks for the detailed problem description!
> >
On 11/20/2012 11:15 PM, Fengguang Wu wrote:
On Tue, Nov 20, 2012 at 10:11:54PM +0800, Jaegeuk Hanse wrote:
On 11/20/2012 04:04 PM, Fengguang Wu wrote:
Hi Claudio,
Thanks for the detailed problem description!
Hi Fengguang,
Another question, thanks in advance.
What's the meaning of interleave
On Tue, Nov 20, 2012 at 10:11:54PM +0800, Jaegeuk Hanse wrote:
> On 11/20/2012 04:04 PM, Fengguang Wu wrote:
> >Hi Claudio,
> >
> >Thanks for the detailed problem description!
>
> Hi Fengguang,
>
> Another question, thanks in advance.
>
> What's the meaning of interleaved reads? If the first pro
On Tue, Nov 20, 2012 at 11:58 AM, Fengguang Wu wrote:
>
>> But if cache hits were to simply update
>> readahead state, it would only mean that read calls behave the same
>> regardless of fadvise calls. I think that's worth pursuing.
>
> Here you are describing an alternative solution that will som
On Tue, Nov 20, 2012 at 10:34:11AM -0300, Claudio Freire wrote:
> On Tue, Nov 20, 2012 at 5:04 AM, Fengguang Wu wrote:
> > Yes. The kernel readahead code by design will outperform simple
> > fadvise in the case of clustered random reads. Imagine the access
> > pattern 1, 3, 2, 6, 4, 9. fadvise wil
> >Yes. The kernel readahead code by design will outperform simple
> >fadvise in the case of clustered random reads. Imagine the access
> >pattern 1, 3, 2, 6, 4, 9. fadvise will trigger 6 IOs literally. While
>
> You mean it will trigger 6 IOs in the POSIX_FADV_RANDOM case or
> POSIX_FADV_WILLNEED
On 11/20/2012 04:04 PM, Fengguang Wu wrote:
Hi Claudio,
Thanks for the detailed problem description!
Hi Fengguang,
Another question, thanks in advance.
What's the meaning of interleaved reads? If the first process readahead
from start ~ start + size - async_size, another process read start
On Tue, Nov 20, 2012 at 5:04 AM, Fengguang Wu wrote:
> Yes. The kernel readahead code by design will outperform simple
> fadvise in the case of clustered random reads. Imagine the access
> pattern 1, 3, 2, 6, 4, 9. fadvise will trigger 6 IOs literally. While
> kernel readahead will likely trigger
On 11/20/2012 04:04 PM, Fengguang Wu wrote:
Hi Claudio,
Thanks for the detailed problem description!
On Fri, Nov 09, 2012 at 04:30:32PM -0300, Claudio Freire wrote:
Hi. First of all, I'm not subscribed to this list, so I'd suggest all
replies copy me personally.
I have been trying to implemen
Hi Claudio,
Thanks for the detailed problem description!
On Fri, Nov 09, 2012 at 04:30:32PM -0300, Claudio Freire wrote:
> Hi. First of all, I'm not subscribed to this list, so I'd suggest all
> replies copy me personally.
>
> I have been trying to implement some I/O pipelining in Postgres (ie:
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