Re: [PATCH 00/33] Adaptive read-ahead V12

[Andrew Morton]

Andi Kleen <ak@xxxxxxx> wrote:
>
> Andrew Morton <akpm@xxxxxxxx> writes:
> > 
> > These are nice-looking numbers, but one wonders.  If optimising readahead
> > makes this much difference to postgresql performance then postgresql should
> > be doing the readahead itself, rather than relying upon the kernel's
> > ability to guess what the application will be doing in the future.  Because
> > surely the database can do a better job of that than the kernel.
> 
> With that argument we should remove all readahead from the kernel? 
> Because it's already trying to guess what the application will do. 
> 
> I suspect it's better to have good readahead code in the kernel
> than in a zillion application.
> 

Wu: "this readahead patch speeds up postgres"

Me: "but postgres could be sped up even more via X"

everyone: "ah, you're saying that's a reason for not altering readahead!".


Would everyone *please* stop being so completely and utterly thick?

Thank you.
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/