Re: [PATCH] Improve heuristic detecting sequential reads

2007-04-12 Thread Jan Kara
On Tue 10-04-07 19:27:22, Andrew Morton wrote: > And shouldn't offset be called prev_offset? Or should prev_page be called > page? Or index? Or prev_index? Or Marmaduke? The naming is all a mess. > > Wanna take a look at all of this, please? OK, attached is a patch which changes prev_page t

Re: [PATCH] Improve heuristic detecting sequential reads

2007-04-11 Thread Jan Kara
On Tue 10-04-07 19:27:22, Andrew Morton wrote: > On Tue, 10 Apr 2007 17:54:11 +0200 Jan Kara <[EMAIL PROTECTED]> wrote: > > > Introduce ra.offset and store in it an offset where the previous read > > ended. This way > > we can detect whether reads are really sequential (and thus we should not >

Re: [PATCH] Improve heuristic detecting sequential reads

2007-04-11 Thread Andi Kleen
> adaptive readahead? Has been in -mm for a year. Problem is, it is > _so_ complete that I just don't know how to merge it. It's huge, and > only Wu understands it. So it's really rather stuck. No benchmark numbers for/against it at all? -Andi > - To unsubscribe from this list: send the line

Re: [PATCH] Improve heuristic detecting sequential reads

2007-04-10 Thread WU Fengguang
On Tue, Apr 10, 2007 at 04:45:40PM -0700, Andrew Morton wrote: > On 11 Apr 2007 00:56:51 +0200 > Andi Kleen <[EMAIL PROTECTED]> wrote: > > > There's a much more complete patchkit for this that gets reposted > > regularly on l-k. Perhaps it would make sense to test that first? > > adaptive readahe

Re: [PATCH] Improve heuristic detecting sequential reads

2007-04-10 Thread Andrew Morton
On Tue, 10 Apr 2007 17:54:11 +0200 Jan Kara <[EMAIL PROTECTED]> wrote: > Introduce ra.offset and store in it an offset where the previous read ended. > This way > we can detect whether reads are really sequential (and thus we should not > mark the page > as accessed repeatedly) or whether they a

Re: [PATCH] Improve heuristic detecting sequential reads

2007-04-10 Thread Andrew Morton
On 11 Apr 2007 00:56:51 +0200 Andi Kleen <[EMAIL PROTECTED]> wrote: > Jan Kara <[EMAIL PROTECTED]> writes: > > > Hello! > > > > In thread http://lkml.org/lkml/2007/3/9/403, we discussed a problem > > with the current heuristic for detecting sequential IO in > > do_generic_mapping_read() - fo

Re: [PATCH] Improve heuristic detecting sequential reads

2007-04-10 Thread Andi Kleen
Jan Kara <[EMAIL PROTECTED]> writes: > Hello! > > In thread http://lkml.org/lkml/2007/3/9/403, we discussed a problem > with the current heuristic for detecting sequential IO in > do_generic_mapping_read() - for small files a page is marked as accessed > only once which can cause a performanc