Hi,
On Wed, Oct 11, 2000 at 09:28:57PM +0100, Chris Evans wrote:
>
> The problem is best described with a little sequence. After using raw i/o
> facilities, streamed block device reads from the same underlying device
> exhibit much poorer performance than before the raw i/o.
>
> Anyone know what's going on? Looks like a bug or inefficiency somewhere in
> the kernel.
It looks as if "hdparm -t" is getting hurt by the fact that raw IO
sets the underlying device's blocksize to 512 bytes (Unix APIs
require that raw character devices allow arbitrary sector-aligned IO).
I'll trace it once I get back from ALS to see if there's anything
obviously funny going on.
Cheers,
Stephen
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
Please read the FAQ at http://www.tux.org/lkml/
This archive was generated by hypermail 2b29 : Sun Oct 15 2000 - 21:00:20 EST